Title: Bad ECM?
Post by: FOX-XR7 on March 03, 2015, 09:05:28 PM
Post by: FOX-XR7 on March 03, 2015, 09:05:28 PM
I saw another thread just started regarding bad ecms, and I didn't want to hijack it, so I figured I'd throw my own on here to get some input. I got my 88 XR7 wired up, completed the maf conversion wiring, and wired up a NGS and a css in the pin 30 and 46 circuit. I have the t5 with a manual O2 harness that is hooked to the existing engine harness. When I turn the key on, I have...NO gauge lights, and NO fuel pump prime. However, with the key flipped to the run position, before ever cranking, the coil will spark once. Still no prime. I troubleshot the ecm power relay today, and everything checked out. I trouble shot the fuel pump relay as far as one man can do it himself. I couldn't check the ground on the relay since it required me to crank the car while watching the test light in the trunk. Lol, I'm just not that flexible. However, when I jumped the fuel pump relay connector, I did here the pump running full boar. Primed to 40 lbs with no problem. I disconnected the used a9l that I bought off ebay, and opened it up. Well, I figured by the Nashua a.k.a. Non fomoco tape, that it had probably had a chip at some point. Sure enough the circuit board is wiped clean where a chip had been installed before. Also, I believe it is fried. ill include some pictures to see what you guys think. Should I see about getting a replacement? Or should I get an A9P, lose the NGS and NCS, and roll with an auto O2 harness, like many folk on here have, and seem to be fine with? Any help is once again appreciated. 
Title: Bad ECM?
Post by: FOX-XR7 on March 03, 2015, 09:06:49 PM
Post by: FOX-XR7 on March 03, 2015, 09:06:49 PM
And a few more. Sorry they're a little hard to see. The unit under the blue cylindrical guy (I lack in the electronic terminology department :hick:) looks like it may be fried where it meets the circuit board. What do you guys think?
Title: Bad ECM?
Post by: jcassity on March 03, 2015, 09:38:34 PM
Post by: jcassity on March 03, 2015, 09:38:34 PM
its a capacitor
it looks like it leaked but it could also be heat sync material as well.. if you can wipe it off, then yeah... it puked.
so,
back to the other thing you said in your post.
With the eec plugged in
with the key forward
up at the diagnostic connector "BIG ONE"
ground the tan / light green wire out
fuel pump will run if all is well.
repeat by going to the trunk *with* relay installed.
ground the tan light green wire and the fuel pump should run
next
with no grounding in either point, if the fuel pump does not prime *but* you can make it run by doing the above then yes the eec is hosed.
keep in mind that you can ground the tan/light green wire and start and run the car and you will probably be able to do so for a long time.
it means that when you turn the key forward the pump runs all the time.
how is this a problem you may ask,, the downside is that its a safety issue.
the other downside is depending on what is jacked up on the eec, you may not be managing the engine correctly.
If your able to pull codes and get the car to run by grounding the tan/light green wire and all is well,,, I would roll with it.
your not going to find a physical ground on the relay because its provided by the eec.
many eec get spiked up the ground side of the relay coil because people are using a paper clip or something to jump past the relay to troubleshoot, and they are guessing as they go in an educated way but,,, injecting 12v up into the tan light green screws up the eec.
it looks like it leaked but it could also be heat sync material as well.. if you can wipe it off, then yeah... it puked.
so,
back to the other thing you said in your post.
With the eec plugged in
with the key forward
up at the diagnostic connector "BIG ONE"
ground the tan / light green wire out
fuel pump will run if all is well.
repeat by going to the trunk *with* relay installed.
ground the tan light green wire and the fuel pump should run
next
with no grounding in either point, if the fuel pump does not prime *but* you can make it run by doing the above then yes the eec is hosed.
keep in mind that you can ground the tan/light green wire and start and run the car and you will probably be able to do so for a long time.
it means that when you turn the key forward the pump runs all the time.
how is this a problem you may ask,, the downside is that its a safety issue.
the other downside is depending on what is jacked up on the eec, you may not be managing the engine correctly.
If your able to pull codes and get the car to run by grounding the tan/light green wire and all is well,,, I would roll with it.
your not going to find a physical ground on the relay because its provided by the eec.
many eec get spiked up the ground side of the relay coil because people are using a paper clip or something to jump past the relay to troubleshoot, and they are guessing as they go in an educated way but,,, injecting 12v up into the tan light green screws up the eec.
Title: Bad ECM?
Post by: FOX-XR7 on March 03, 2015, 10:26:23 PM
Post by: FOX-XR7 on March 03, 2015, 10:26:23 PM
Alright, I'll try that fuel pump grounding tomorrow. I did already jump power at the fuel pump relay today and got it to run. I'm sorry I forgot to mention the biggest issue....I get one spark when I turn the key to run, but when cranking I get no spark. Then turning the key back past run to the off position the coil sparks again on "run" as I'm turning key off. So, I'm a bit confuzzled as to why it is doing that. Rarely can I get it to spark on cranking. But it has intermittently.
I did just try wiping it off, but to no avail....I'm thinking it's definitely junk. I just found another spot that is definitely toast.
I did just try wiping it off, but to no avail....I'm thinking it's definitely junk. I just found another spot that is definitely toast.
Title: Bad ECM?
Post by: jcassity on March 04, 2015, 12:48:44 PM
Post by: jcassity on March 04, 2015, 12:48:44 PM
these things rarely go bad.. seriously... to e honest they are likely to be the very last thing to go bad on the car.
for as complicated as it all looks , there is some really old but reliable tech inside.
spark delivery is managed by a separate system all on the distributor.
the exterior module in combination with the inside pick up (replaced points) manages when at what times in the rotation of the distributor will the coil be allowed to actually deliver a spark.
"no fuel delivery" will not prevent "no spark"
if its easier to talk though this stuff, and also have the 88evtm opened up per below, the feel free, 304 772 3411
ideally you want to focus on page 58
for as complicated as it all looks , there is some really old but reliable tech inside.
spark delivery is managed by a separate system all on the distributor.
the exterior module in combination with the inside pick up (replaced points) manages when at what times in the rotation of the distributor will the coil be allowed to actually deliver a spark.
"no fuel delivery" will not prevent "no spark"
if its easier to talk though this stuff, and also have the 88evtm opened up per below, the feel free, 304 772 3411
ideally you want to focus on page 58
Title: Bad ECM?
Post by: softtouch on March 04, 2015, 04:47:17 PM
Post by: softtouch on March 04, 2015, 04:47:17 PM
Unplug the SPOUT jumper and see if you get spark while cranking. If you do, the EEC has more problems than just the fuel pump relay circuit.
Title: Bad ECM?
Post by: TurboCoupe50 on March 04, 2015, 05:24:50 PM
Post by: TurboCoupe50 on March 04, 2015, 05:24:50 PM
Yeah worry about the spark first, as mentioned ECM won't kill that..
I had to replace a similar cap in my '93 Lightning PCM that was leaking(it's a common issue with late OBD-I F-series PCM, seen one that actually flamed, burned a hole in board)... It ran but was hard to start due to it was extremely rich when cold, to the point of flooding and puffing black smoke... Also caused the transmission to shift like it had a full race valve body in it, would bark tires at 20 MPH under light throttle... Once I repl the cap it was fine again... Used 1st gen Lightning PCM are all but unobtainable, and new ones are non existent, have to send them to a rebuilder as there are no cores(or at least were none three years ago when I had my issues)
(http://amradio.freeiz.com/Lightningecm.jpg)
I had to replace a similar cap in my '93 Lightning PCM that was leaking(it's a common issue with late OBD-I F-series PCM, seen one that actually flamed, burned a hole in board)... It ran but was hard to start due to it was extremely rich when cold, to the point of flooding and puffing black smoke... Also caused the transmission to shift like it had a full race valve body in it, would bark tires at 20 MPH under light throttle... Once I repl the cap it was fine again... Used 1st gen Lightning PCM are all but unobtainable, and new ones are non existent, have to send them to a rebuilder as there are no cores(or at least were none three years ago when I had my issues)
(http://amradio.freeiz.com/Lightningecm.jpg)
Title: Bad ECM?
Post by: FOX-XR7 on March 04, 2015, 10:49:32 PM
Post by: FOX-XR7 on March 04, 2015, 10:49:32 PM
Ended up tinkering with the car today for a bit under the cellular guidance of jcassity (thanks for the help!), and we determined the fuel pump relay is gtg. It is getting power from the battery, and from the erc power relay. However, it is not receiving a ground. IM gonna try and work on it again tomorrow before work.
To softtouch, I unplugged the spout connector, cranked it, and got beautiful blue sparks from the coil for days! But only with the spout unplugged. We were thinking the 88s had the spark controlled by the fuel pump grounding by the ecm? What does it mean if I get spark with spout unplugged, but no spark with it plugged in? Still no fuel pump priming, and no warning lights on the gauge cluster. loss of thought for now...back to the EVTM drawing board. Will proceed with more tries tomorrow.
To softtouch, I unplugged the spout connector, cranked it, and got beautiful blue sparks from the coil for days! But only with the spout unplugged. We were thinking the 88s had the spark controlled by the fuel pump grounding by the ecm? What does it mean if I get spark with spout unplugged, but no spark with it plugged in? Still no fuel pump priming, and no warning lights on the gauge cluster. loss of thought for now...back to the EVTM drawing board. Will proceed with more tries tomorrow.
Title: Bad ECM?
Post by: Beau on March 04, 2015, 10:56:05 PM
Post by: Beau on March 04, 2015, 10:56:05 PM
It means the EEC is bad, in a nutshell. I'll leave it to the smart guys to tell you exactly what's wrong, though.
I just sold the A9T that I had last week...sorry dude.
I just sold the A9T that I had last week...sorry dude.
Title: Bad ECM?
Post by: FOX-XR7 on March 04, 2015, 11:06:44 PM
Post by: FOX-XR7 on March 04, 2015, 11:06:44 PM
Lol, no sweat. I'm reading other stuff, and I'm wondering if it could be that I forgot a ground somewhere, or I don't have enough grounds....or I could just be in denial of a junk puter that I don't wanna she'll out 170 bucks for a remanned one just yet...atleast until all other tests have been accounted for... But who knows? Just the magic blue smoke creating wizards who live deep within the electrical underworld. ;)
Title: Bad ECM?
Post by: softtouch on March 05, 2015, 12:28:39 AM
Post by: softtouch on March 05, 2015, 12:28:39 AM
Quote from: FOX-XR7;445597
Ended up tinkering with the car today for a bit under the cellular guidance of jcassity (thanks for the help!), and we determined the fuel pump relay is gtg. It is getting power from the battery, and from the erc power relay. However, it is not receiving a ground.
Quote
We were thinking the 88s had the spark controlled by the fuel pump grounding by the ecm?
Quote
What does it mean if I get spark with spout unplugged, but no spark with it plugged in?
Quote
and no warning lights on the gauge cluster.
Title: Bad ECM?
Post by: FOX-XR7 on March 05, 2015, 07:35:34 AM
Post by: FOX-XR7 on March 05, 2015, 07:35:34 AM
There are no warning or gauge lights at all in run or start. No cel, no brake light, batt light, or oil light. Gauges are all dead with key in run or cranking. Tach doesn't bounce when cranking either.
Title: Bad ECM?
Post by: jcassity on March 05, 2015, 11:42:43 AM
Post by: jcassity on March 05, 2015, 11:42:43 AM
im gonna chime in here in a min,, gotta pull down and show you all something that I found to be totally impossible.
Title: Bad ECM?
Post by: jcassity on March 05, 2015, 12:10:40 PM
Post by: jcassity on March 05, 2015, 12:10:40 PM
**this is a 1988 chassis, and the evtm link below
in the car test- symptom= no fuel pressures at fuel rail, no spark
-eec appears to not be providing K2 coil with a ground
-Fuel pump runs when yellow and pink/blk are jumped out
-added manual ground to fuel pump relay
-relay high current contacts audibly click
-power to relay coil is present
-ground is again manually provided
-no power out on ckt 787 to the fuel pump
Fuel pump relay out of the car test
energized k2 manually
found high current contacts to have continuity
first pic below is the 87evtm 5.0 fuel pump layout
next pic is the equal circuit found in 1988 5.0 evtm
next two pics are for 87 3.8L and 88 3.8L pertaining to ckt 787 branch ckt, 1987 its not connected, in 1988 it is.
I am still speculating that there is a revision in engine management in that the eec is given the power to pull out power to the fuel pump and also manage spark for possibly safety reasons
I say this because for the 87 3.8L, the parallel ckt 787 is not connected.
The parallel ckt 787 for the 88 3.8L is connected.
What if this ckt is wired for the 1988 3.8Lonly ?
why would they decide to include the branch ckt 787 for the 5.0L in 1988 only and illustrate it as NC?
Why would they only in 1988 3.8L wire it up to pin 8, yet on 1987 no wire it up?
in the car test- symptom= no fuel pressures at fuel rail, no spark
-eec appears to not be providing K2 coil with a ground
-Fuel pump runs when yellow and pink/blk are jumped out
-added manual ground to fuel pump relay
-relay high current contacts audibly click
-power to relay coil is present
-ground is again manually provided
-no power out on ckt 787 to the fuel pump
Fuel pump relay out of the car test
energized k2 manually
found high current contacts to have continuity
first pic below is the 87evtm 5.0 fuel pump layout
next pic is the equal circuit found in 1988 5.0 evtm
next two pics are for 87 3.8L and 88 3.8L pertaining to ckt 787 branch ckt, 1987 its not connected, in 1988 it is.
I am still speculating that there is a revision in engine management in that the eec is given the power to pull out power to the fuel pump and also manage spark for possibly safety reasons
I say this because for the 87 3.8L, the parallel ckt 787 is not connected.
The parallel ckt 787 for the 88 3.8L is connected.
What if this ckt is wired for the 1988 3.8Lonly ?
why would they decide to include the branch ckt 787 for the 5.0L in 1988 only and illustrate it as NC?
Why would they only in 1988 3.8L wire it up to pin 8, yet on 1987 no wire it up?
Title: Bad ECM?
Post by: jcassity on March 05, 2015, 12:44:20 PM
Post by: jcassity on March 05, 2015, 12:44:20 PM
here is the 87 and 88 3.8L equal fuel pump layouts
Title: Bad ECM?
Post by: jcassity on March 05, 2015, 12:45:07 PM
Post by: jcassity on March 05, 2015, 12:45:07 PM
again,
out of the car the fuel pump relay works fine.
out of the car the fuel pump relay works fine.
Title: Bad ECM?
Post by: Haystack on March 05, 2015, 01:16:52 PM
Post by: Haystack on March 05, 2015, 01:16:52 PM
How's the ignition switch look?
All gauges dead, fuel pump and ecm not working. All point to a lack of power, or lack of ground. Ignition switch turns all of them on, so in my mind it seems most likely.
All gauges dead, fuel pump and ecm not working. All point to a lack of power, or lack of ground. Ignition switch turns all of them on, so in my mind it seems most likely.
Title: Bad ECM?
Post by: FOX-XR7 on March 05, 2015, 01:33:36 PM
Post by: FOX-XR7 on March 05, 2015, 01:33:36 PM
Ignition switch is new. I ordered it a few months ago from latemodelresto. I went over today to tinker some more ....found that pins 40 and 60 weren't grounded like they should've been, so I properly grounded them to the battery negative cable. Tried it then, still no lights, no fuel pump, no spark. Maybe I'm missing another ground somewhere? I read that a way to see if the ECM is powering up, is to turn key on, and probe the Orange wire on the tps. If you have 5 volts, then the computer is powering up. Is this a correct statement? In which case, the computer is "powering up" but I still have no fuel pump priming, warning lights, or spark. Could I be forgetting a ground somewhere?
Title: Bad ECM?
Post by: FOX-XR7 on March 05, 2015, 01:35:52 PM
Post by: FOX-XR7 on March 05, 2015, 01:35:52 PM
These are pics of the ground connection for 40 and 60 that I didn't have grounded to the battery before. I now have them grounded, but still no difference.
Title: Bad ECM?
Post by: Haystack on March 05, 2015, 02:23:59 PM
Post by: Haystack on March 05, 2015, 02:23:59 PM
The ignition switch powers your dash lights. It is two yellow or orange wires sliced into a single pin. If one wire is off, you have no dash lights.
A bad connector or splice can carry a light load, then overheat and fail under load. Imho, same thing happened to my 86 cougar. I replaced the ignition switch, my entire dash went dead and the car would randomly not start. Id hit a bump and the dash would light up for a bit till the next bump.
I think the ignition is sending 12v's to the relays, then when you try to start it the wire or connection overheats and fails. This would also explain why you only have momentary spark.
Check this link, http://sbftech.com/index.php?topic=588.0 if you can't find any problems with the ignition or 12 positive supply.
A bad connector or splice can carry a light load, then overheat and fail under load. Imho, same thing happened to my 86 cougar. I replaced the ignition switch, my entire dash went dead and the car would randomly not start. Id hit a bump and the dash would light up for a bit till the next bump.
I think the ignition is sending 12v's to the relays, then when you try to start it the wire or connection overheats and fails. This would also explain why you only have momentary spark.
Check this link, http://sbftech.com/index.php?topic=588.0 if you can't find any problems with the ignition or 12 positive supply.
Title: Bad ECM?
Post by: softtouch on March 05, 2015, 03:56:01 PM
Post by: softtouch on March 05, 2015, 03:56:01 PM
Quote from: FOX-XR7;445622
Ignition switch is new. I ordered it a few months ago from latemodelresto. I went over today to tinker some more ....found that pins 40 and 60 weren't grounded like they should've been, so I properly grounded them to the battery negative cable.
Quote
Tried it then, still no lights, no fuel pump, no spark.
Quote
Maybe I'm missing another ground somewhere?
Quote
I read that a way to see if the ECM is powering up, is to turn key on, and probe the Orange wire on the tps. If you have 5 volts, then the computer is powering up. Is this a correct statement?
What kind of cluster do you have, buttstuffog or digital?
Title: Bad ECM?
Post by: softtouch on March 05, 2015, 04:12:59 PM
Post by: softtouch on March 05, 2015, 04:12:59 PM
Check fuse 18 for the lights problem.
Title: Bad ECM?
Post by: jcassity on March 05, 2015, 06:29:19 PM
Post by: jcassity on March 05, 2015, 06:29:19 PM
full buttstuffog cluster,,
but from what he told me its from a TC...
I brought up ckt 787 parallel branch because while dealing with auto lamps in my sons 88,, it lead me to so many incorrect things for 88 inside the evtm.
Waiting for the original poster to chime in to confirm if "pin8 has that wire" on the computer or not.... and if he does, then that means yet another 1988 EVTM mistake I will note.
if its present on the 88 5.0L like it is on the 88 3.8L,, then it might be supervising spark and fuel... since we know the fuel pump relay itself is good.
but from what he told me its from a TC...
I brought up ckt 787 parallel branch because while dealing with auto lamps in my sons 88,, it lead me to so many incorrect things for 88 inside the evtm.
Waiting for the original poster to chime in to confirm if "pin8 has that wire" on the computer or not.... and if he does, then that means yet another 1988 EVTM mistake I will note.
if its present on the 88 5.0L like it is on the 88 3.8L,, then it might be supervising spark and fuel... since we know the fuel pump relay itself is good.
Title: Bad ECM?
Post by: softtouch on March 05, 2015, 06:53:27 PM
Post by: softtouch on March 05, 2015, 06:53:27 PM
Scott, the 88 3.8 is a big change. all the older models are CFI. It looks to me like 88 3.8 EEC is checking for error code 95.(secondary fuel pump failure) . Since the 5.0 EEC doesn't check for that, they didn't run the wire back to the EEC.
Title: Bad ECM?
Post by: softtouch on March 05, 2015, 07:03:31 PM
Post by: softtouch on March 05, 2015, 07:03:31 PM
FOX-XR7
I am curious about the NGS & CSS wiring you did. I see it involves EEC pin 46 which is the EEC signal return (logic ground)
The stock set-up for this car puts 12v on pin 30 with the ignition switch in START. If 12v got to pin 46 through the NGS, that is a problem.
Jcassity's post 4 shows the pin out for the test connector. See if you have 12v on the "sig rtn" with the ignition in start.
Can you post a link to the instructions you used for the Mass Air conversion.
I am curious about the NGS & CSS wiring you did. I see it involves EEC pin 46 which is the EEC signal return (logic ground)
The stock set-up for this car puts 12v on pin 30 with the ignition switch in START. If 12v got to pin 46 through the NGS, that is a problem.
Jcassity's post 4 shows the pin out for the test connector. See if you have 12v on the "sig rtn" with the ignition in start.
Can you post a link to the instructions you used for the Mass Air conversion.
Title: Bad ECM?
Post by: FOX-XR7 on March 05, 2015, 07:44:34 PM
Post by: FOX-XR7 on March 05, 2015, 07:44:34 PM
When I get back over there, I will check fuse 18 for the lights, and pin 8 on the eec. I used a fiveology racing maf conversion from ebay. I read the directions and I cross referenced them to coolcats, and all the pins they had to swap over matched. So because coolcats matched the instructions, I went for it. I was definitely thrown by the fact that the ground didn't do anything different. when I go back to the shop, I will unplug the ground at key on and check the tps ref. Vol. Along with checking pin 46 voltage while cranking. My father in law checked continuity from a ground strap between the negative post and the fenderwell. And it beeped with key off. Then with key in run, the coil sparks once, and he loses continuity on that same exact negative wire. Wtf?!? How does that work?
Title: Bad ECM?
Post by: FOX-XR7 on March 05, 2015, 07:55:32 PM
Post by: FOX-XR7 on March 05, 2015, 07:55:32 PM
I also wired my ngs and css in series. Pin 30 goes to my css, then to ngs, then to pin 46. I thought that's how it was supposed to be wired, but I have Ben wrong before. Haha
Title: Bad ECM?
Post by: FOX-XR7 on March 05, 2015, 09:29:43 PM
Post by: FOX-XR7 on March 05, 2015, 09:29:43 PM
Yeah, the gauge cluster is out of an 87/88 tc. All the gauges are the tc gauges less the tach. The tach is the original one from the car. I changed clusters because my circuit board In the original was all torn up and peeling.
Title: Bad ECM?
Post by: softtouch on March 06, 2015, 06:06:08 PM
Post by: softtouch on March 06, 2015, 06:06:08 PM
This 93 5.0 Mustang diagram looks like what you are doing.
If you removed the stock AOD wire and added your new wire to pin 30 you are good.
If you spliced your new wire into the stock wire, you have a problem.
I am guessing you are using 88 Cougar 5.0 wiring harness.
If you removed the stock AOD wire and added your new wire to pin 30 you are good.
If you spliced your new wire into the stock wire, you have a problem.
I am guessing you are using 88 Cougar 5.0 wiring harness.
Title: Bad ECM?
Post by: jcassity on March 06, 2015, 07:26:32 PM
Post by: jcassity on March 06, 2015, 07:26:32 PM
LOL, so you guys are wayyyyyyyyyyyyyyy over there and im still over here saying........
"why doesn't the relay have output power" ~as in what I posted earlier~ I thought someone else would have found this to be impossible as well
I mean,,, the darn thing works,,
it clicks ,
it has continuity when manually triggered,
we provided a manual ground to it when re-installed in the car.... and it clicks over when in the car
it doesn't pass power out?
"why doesn't the relay have output power" ~as in what I posted earlier~ I thought someone else would have found this to be impossible as well
I mean,,, the darn thing works,,
it clicks ,
it has continuity when manually triggered,
we provided a manual ground to it when re-installed in the car.... and it clicks over when in the car
it doesn't pass power out?
Title: Bad ECM?
Post by: FOX-XR7 on March 06, 2015, 07:46:35 PM
Post by: FOX-XR7 on March 06, 2015, 07:46:35 PM
Quote from: softtouch;445682
This 93 5.0 Mustang diagram looks like what you are doing.
If you removed the stock AOD wire and added your new wire to pin 30 you are good.
If you spliced your new wire into the stock wire, you have a problem.
I am guessing you are using 88 Cougar 5.0 wiring harness.
Now that you mention that, I did just splice into the existing wire at pin 30. I didn't take out the wire and replace it with the one I ran new. And yes, I have an 88 cougar 5.0 wiring harness that I'm utilizing. Trans harness is off of a 5.0 foxbody mustang. O2 harness is off of a 89 5.0 5 speed mustang harness.
Sorry Scott, I didn't get a chance to run over to the shop today to check in pin 8. I did wire up aa secondary fuel pump circuit wire for the maf conversion. Perhaps this has something that is negatively affecting the relay?
Title: Bad ECM?
Post by: TurboCoupe50 on March 06, 2015, 08:47:22 PM
Post by: TurboCoupe50 on March 06, 2015, 08:47:22 PM
Quote from: FOX-XR7;445689
I did wire up aa secondary fuel pump circuit wire for the maf conversion. Perhaps this has something that is negatively affecting the relay?
I have wired it on the T-Bird, but when the POS Carter F/P failed at a little over a year, was no code as there was power...
BTW the same A9P ECM was used on both, kept the MAF components when I sold the Stang...
Title: Bad ECM?
Post by: FOX-XR7 on March 06, 2015, 10:37:06 PM
Post by: FOX-XR7 on March 06, 2015, 10:37:06 PM
Ahh ok. That makes sense. I may try that if I can resolve my issue. too bad about your carter fuel pump...that's what I am running! Lol. Hopefully I have a little better luck. I thought about using an A9p just so I don't have to worry about frying it, but I really don't wanna deal with a hanging idle that I've read can happen if you run a 5 speed with an A9P. Was yours a 5 speed/9P combo? Did you have this problem?
Title: Bad ECM?
Post by: TurboCoupe50 on March 06, 2015, 11:05:02 PM
Post by: TurboCoupe50 on March 06, 2015, 11:05:02 PM
I searched out a low option, automatic TC specifically for the swap and now have a AOD in mine, used a '87 5.0 T-Bird harness that I converted to mass air prior to installing it...
Title: Bad ECM?
Post by: softtouch on March 07, 2015, 01:14:14 AM
Post by: softtouch on March 07, 2015, 01:14:14 AM
Since you have reconnected the EEC and EEC relay ground when you replugged C434 lets do another fuel pump test.
At the self test connector, ground the fuel pump test pin and see if the pump runs with the key in run.
This will be the tan/green wire at the connector.
At the self test connector, ground the fuel pump test pin and see if the pump runs with the key in run.
This will be the tan/green wire at the connector.
Title: Bad ECM?
Post by: FOX-XR7 on March 11, 2015, 02:02:15 PM
Post by: FOX-XR7 on March 11, 2015, 02:02:15 PM
I pulled fuse 18, and it was blown. So I replaced it. Now my seatbelt light comes on, and the door ajar light illuminates as well with the key in run.
Title: Bad ECM?
Post by: FOX-XR7 on March 11, 2015, 02:12:15 PM
Post by: FOX-XR7 on March 11, 2015, 02:12:15 PM
I worked on the car a bit today, and I checked pin 8 on the harness and there is no wire there. I found another connector for what I believe is another ground wire beside the battery box. Pictures to follow below. I snipped the aod wire to pin 30, and rewired my NGS and Css in parallel, and ran it from 30 to the existing pin 46 wire, bypassing the 12 volt wire from ignition switch in start. I then turned key to run, and still no fuel pump. When I crank, still no fuel pump. I will pull the ignition switch apart next and update when I'm done.
These are the 2 connectors I saw unplugged. I think they are ground wires? Or are they something else?
These are the 2 connectors I saw unplugged. I think they are ground wires? Or are they something else?
Title: Bad ECM?
Post by: softtouch on March 11, 2015, 02:16:47 PM
Post by: softtouch on March 11, 2015, 02:16:47 PM
Wire color?
Title: Bad ECM?
Post by: FOX-XR7 on March 11, 2015, 06:04:01 PM
Post by: FOX-XR7 on March 11, 2015, 06:04:01 PM
Softtouch, the wire colors are black. Two black wires on the male connector end, and one black wire on the female end.
I called Scott, and we worked through some more troubleshooting to find out that there was indeed continuity over the high current side of the relay when it was energized on the bench. (Outside the car) what we couldn't understand, was the inexplainable reason as to why it would energize outside, but in the car, it would energize and the fuel pump would not run. Well, as time went by, and scenarios were running out, I realized that when I did the maf conversion, and spliced a secondary fuel pump circuit wire from pin 19 to the pink/black wire that runs to the pump itself, I neglected to put the fuel pump power wire back into the appropriate slot in the connector. Therefore, it was in the blank spot, and the relay was energizing, the power was not going anywhere. Tah dah! Stupidity on my part. Haha. With this plugged correctly in place, the fuel pump primes and builds 38 lbs for 3-5 seconds, and there is now plenty of spark when cranking. Just no start. So, I believe I may have stabbed my distributor wrong when swapping back from carb to efi. So thank you all for the help, and I'll give a follow up with whatever else may happen. Hopefully she starts, and if not.....well, Ill mention that too. ;)
I called Scott, and we worked through some more troubleshooting to find out that there was indeed continuity over the high current side of the relay when it was energized on the bench. (Outside the car) what we couldn't understand, was the inexplainable reason as to why it would energize outside, but in the car, it would energize and the fuel pump would not run. Well, as time went by, and scenarios were running out, I realized that when I did the maf conversion, and spliced a secondary fuel pump circuit wire from pin 19 to the pink/black wire that runs to the pump itself, I neglected to put the fuel pump power wire back into the appropriate slot in the connector. Therefore, it was in the blank spot, and the relay was energizing, the power was not going anywhere. Tah dah! Stupidity on my part. Haha. With this plugged correctly in place, the fuel pump primes and builds 38 lbs for 3-5 seconds, and there is now plenty of spark when cranking. Just no start. So, I believe I may have stabbed my distributor wrong when swapping back from carb to efi. So thank you all for the help, and I'll give a follow up with whatever else may happen. Hopefully she starts, and if not.....well, Ill mention that too. ;)
Title: Bad ECM?
Post by: FOX-XR7 on March 13, 2015, 10:32:59 AM
Post by: FOX-XR7 on March 13, 2015, 10:32:59 AM
So i reset cylinder one to tdc compression and I stabbed the distributor correctly, and lined the rotor up to fire cylinder one. I gave her a crank, and she fired right up. Then died. Haha, can't get her to run for more than a second. Back to the drawing board.
Title: Bad ECM?
Post by: jcassity on March 13, 2015, 07:00:40 PM
Post by: jcassity on March 13, 2015, 07:00:40 PM
http://www.foxtbirdcougarforums.com/showthread.php?38584-Cranks-but-won-t-start-is-the-ECM-bad
now you should e ready to pull codes with the link above,,
my diy link below lists them all
now you should e ready to pull codes with the link above,,
my diy link below lists them all
Title: Bad ECM?
Post by: TurboCoupe50 on March 13, 2015, 07:07:12 PM
Post by: TurboCoupe50 on March 13, 2015, 07:07:12 PM
Assuming it dies at the moment the switch returns to run you either have a wiring issue or or a bad ign switch... If it were loosing fuel pressure will run at least six or eight seconds before stumbling and then dieing...
I doubt either problem will set a code though you might get a 15 if is a power loss to EEC...
I doubt either problem will set a code though you might get a 15 if is a power loss to EEC...
Title: Bad ECM?
Post by: jcassity on March 14, 2015, 09:15:24 AM
Post by: jcassity on March 14, 2015, 09:15:24 AM
Quote from: TurboCoupe50;446009
Assuming it dies at the moment the switch returns to run you either have a wiring issue or or a bad ign switch.....
not that makes better sense
Title: Bad ECM?
Post by: FOX-XR7 on March 14, 2015, 03:19:12 PM
Post by: FOX-XR7 on March 14, 2015, 03:19:12 PM
Well it's like it wants to run, because the first time I cranked it, I returned the key to run and it ran for about a second before stumbling and dying. I checked tps voltage on the green wire with koeo, and I got 5 volts. When I slowly opened the throttle blade, it climbed to 5.04 volts. Then back down as I closed it. I tried the wiggle test and it never jumped open voltage. So I'm wondering if the pin 46 could have something to do with it. Should pin 46 on koeo have any voltage? Or none? I will check code on probably Monday when I go over. I'll let you know
Title: Bad ECM?
Post by: softtouch on March 14, 2015, 05:37:45 PM
Post by: softtouch on March 14, 2015, 05:37:45 PM
Quote from: FOX-XR7;446041
Well it's like it wants to run, because the first time I cranked it, I returned the key to run and it ran for about a second before stumbling and dying. I checked tps voltage on the green wire with koeo, and I got 5 volts. When I slowly opened the throttle blade, it climbed to 5.04 volts. Then back down as I closed it. I tried the wiggle test and it never jumped open voltage. So I'm wondering if the pin 46 could have something to do with it. Should pin 46 on koeo have any voltage? Or none? I will check code on probably Monday when I go over. I'll let you know
To confirm it's blown, run the KOEO tests with the STI jumped to Sig Rtn. If blown you will get no codes not even the 11 good code.
Rerun the KOEO with STI jumped to ground. I think you will get some codes .
Someone fixed this on this forum a while back. He opened up the EEC and found where pin 46 entered the printed circuit board.
He traced the land pattern and found where it burned off. He even had pictures, I'll see if I can find the thread.
Title: Bad ECM?
Post by: FOX-XR7 on March 14, 2015, 07:30:05 PM
Post by: FOX-XR7 on March 14, 2015, 07:30:05 PM
Quote from: softtouch;446043
Sorry, I looks like your Signal Return (pin 46) is zapped. Signal Return is the logic ground for all the 5v stuff outside and inside the EEC.
To confirm it's blown, run the KOEO tests with the STI jumped to Sig Rtn. If blown you will get no codes not even the 11 good code.
Rerun the KOEO with STI jumped to ground. I think you will get some codes .
Someone fixed this on this forum a while back. He opened up the EEC and found where pin 46 entered the printed circuit board.
He traced the land pattern and found where it burned off. He even had pictures, I'll see if I can find the thread.
Alright, I will try these methods and let you know. I would very much appreciate that link to the repair.
Title: Bad ECM?
Post by: softtouch on March 14, 2015, 08:59:15 PM
Post by: softtouch on March 14, 2015, 08:59:15 PM
Could not find the link I remembered but I did find this on the corral forum. It shows the sig rtn land blown.
If you can find the blown spot you could try to solder in a small wire to bypass the bad spot.
http://i154.photobucket.com/albums/s276/slow88lx/mustangcomputer001circle.jpg
If you can find the blown spot you could try to solder in a small wire to bypass the bad spot.
http://i154.photobucket.com/albums/s276/slow88lx/mustangcomputer001circle.jpg
Title: Bad ECM?
Post by: FOX-XR7 on March 14, 2015, 09:52:57 PM
Post by: FOX-XR7 on March 14, 2015, 09:52:57 PM
Quote from: softtouch;446043
Sorry, I looks like your Signal Return (pin 46) is zapped. Signal Return is the logic ground for all the 5v stuff outside and inside the EEC.
To confirm it's blown, run the KOEO tests with the STI jumped to Sig Rtn. If blown you will get no codes not even the 11 good code.
Rerun the KOEO with STI jumped to ground. I think you will get some codes .
Someone fixed this on this forum a while back. He opened up the EEC and found where pin 46 entered the printed circuit board.
He traced the land pattern and found where it burned off. He even had pictures, I'll see if I can find the thread.
Alright, I will try these methods and let you know. I would very much appreciate that link to the repair.
Title: Bad ECM?
Post by: FOX-XR7 on March 14, 2015, 09:55:34 PM
Post by: FOX-XR7 on March 14, 2015, 09:55:34 PM
Thank you. I will open my ecm and take photos to post.
Title: Bad ECM?
Post by: Haystack on March 15, 2015, 01:10:39 AM
Post by: Haystack on March 15, 2015, 01:10:39 AM
Yep, this can be caused by a bad chassi ground by the battery. It forces the sigrtn ground to run through parts of the computer that aren't designed for that kind of load.
That small block ford no start write up i referenced you to has steps to check for this in the very first bit.
My buddy's third had a random dying issue. It ended up being both the fuel pump and that chassi ground by the battery. The connector corroded and was making an intermittent connection. Luckily we replaced the pump and ground wire and i out nearly 100k miles on it when i bought it off of him with no issues. His tps was reading 12v's before we found it.
That small block ford no start write up i referenced you to has steps to check for this in the very first bit.
My buddy's third had a random dying issue. It ended up being both the fuel pump and that chassi ground by the battery. The connector corroded and was making an intermittent connection. Luckily we replaced the pump and ground wire and i out nearly 100k miles on it when i bought it off of him with no issues. His tps was reading 12v's before we found it.
Title: Bad ECM?
Post by: FOX-XR7 on March 15, 2015, 01:34:30 AM
Post by: FOX-XR7 on March 15, 2015, 01:34:30 AM
Quote from: Haystack;446072
Yep, this can be caused by a bad chassi ground by the battery. It forces the sigrtn ground to run through parts of the computer that aren't designed for that kind of load.
That small block ford no start write up i referenced you to has steps to check for this in the very first bit.
My buddy's third had a random dying issue. It ended up being both the fuel pump and that chassi ground by the battery. The connector corroded and was making an intermittent connection. Luckily we replaced the pump and ground wire and i out nearly 100k miles on it when i bought it off of him with no issues. His tps was reading 12v's before we found it.
Yeah I checked into that thread yet again. ( I referred to that for my no spark help) and I found a thread on how to troubleshoot the sig rtn. So I'm gonna try these things from Joel. I'll let you guys know.
Title: Bad ECM?
Post by: FOX-XR7 on March 17, 2015, 02:40:52 PM
Post by: FOX-XR7 on March 17, 2015, 02:40:52 PM
Well gentleman, I tried pulling the codes by jumping the Sti and sig rtn, but I got nothing but. Steady volt lamp with koeo. So I then tried pulling them by grounding the sti to ground, on the negative batt terminal, and I was able to pull 7 codes, and then 2 continuous memory codes. The 7 codes are as follows:
22- MAP out of range
35- EGR pressure feedback regulator circuit
51- coolant temp sensor out of range
53- TPS input out of range
54- ACT sensor
67- Neutral Drive Switch Circuit
95- Fuel Pump Circuit problem.
Then I had 9 seconds, followed by a blink, then 9 more seconds, then I got a code 95. Fuel pump circuit problem.
So, I found it quite obvious there was an inevitable issue with pin 46, just as Softtouch said he was afraid of. I figured since the sig rtn wire goes to the MAP, TPS, EGR, ECT and ACT sensors, and they all are throwing codes.....I decided to pull the computer. I opened her up, and sure enough, through the overwhelming stench of burnt electronic smell, the infamous pin 46 circuit was burned. (I'll put a picture up of it then) I took the voltmeter, put it on continuity check, and pinned the ends across the burned gap, just to make sure. Needless to say, I go a big fat O.L on my meter. So I think I will try to solder a thin 28 gauge wire across it, like I saw on the corral I belive it was. Any thoughts? Should I try mending it to save the $$ or should I take it to advance and get a remanned computer? Thanks for your continued help guys. I really appreciate it.
22- MAP out of range
35- EGR pressure feedback regulator circuit
51- coolant temp sensor out of range
53- TPS input out of range
54- ACT sensor
67- Neutral Drive Switch Circuit
95- Fuel Pump Circuit problem.
Then I had 9 seconds, followed by a blink, then 9 more seconds, then I got a code 95. Fuel pump circuit problem.
So, I found it quite obvious there was an inevitable issue with pin 46, just as Softtouch said he was afraid of. I figured since the sig rtn wire goes to the MAP, TPS, EGR, ECT and ACT sensors, and they all are throwing codes.....I decided to pull the computer. I opened her up, and sure enough, through the overwhelming stench of burnt electronic smell, the infamous pin 46 circuit was burned. (I'll put a picture up of it then) I took the voltmeter, put it on continuity check, and pinned the ends across the burned gap, just to make sure. Needless to say, I go a big fat O.L on my meter. So I think I will try to solder a thin 28 gauge wire across it, like I saw on the corral I belive it was. Any thoughts? Should I try mending it to save the $$ or should I take it to advance and get a remanned computer? Thanks for your continued help guys. I really appreciate it.
Title: Bad ECM?
Post by: TurboCoupe50 on March 17, 2015, 04:08:24 PM
Post by: TurboCoupe50 on March 17, 2015, 04:08:24 PM
Gently se the coating from the traces and lay your wire on them, solder in place...
Doesn't cost anything and you may get lucky...
Doesn't cost anything and you may get lucky...
Title: Bad ECM?
Post by: jcassity on March 17, 2015, 06:48:50 PM
Post by: jcassity on March 17, 2015, 06:48:50 PM
so what is the root cause here,, improper 02 harness for Mass air or what?
Title: Bad ECM?
Post by: Haystack on March 17, 2015, 08:43:17 PM
Post by: Haystack on March 17, 2015, 08:43:17 PM
Id say not running the ground between the chassis and ecm. It forced the sigrtn load to run though pins 20 40 and 60 and puts excess load through the traces and eventually burns it up.
Or at least that's how i remember it being explained to me a few years ago.
Or at least that's how i remember it being explained to me a few years ago.
Title: Bad ECM?
Post by: FOX-XR7 on March 17, 2015, 08:59:34 PM
Post by: FOX-XR7 on March 17, 2015, 08:59:34 PM
I'm going to try and go back over tomorrow and see what happens. I'm worried I'll blow it again. Could it have been a bad O2 harness? I'm using a manual mustang harness. Before I plug in the computer, should I check for voltage on pin 46, with key on, cranking, clutch in, clutch out, and off and all that? What voltage is needed to burn up the trace? More than like 1 volt? Will milli volts burn it? Here's a picture of the wire my father in law helped solder in.
Title: Bad ECM?
Post by: FOX-XR7 on March 17, 2015, 09:03:09 PM
Post by: FOX-XR7 on March 17, 2015, 09:03:09 PM
Title: Bad ECM?
Post by: jcassity on March 17, 2015, 09:53:30 PM
Post by: jcassity on March 17, 2015, 09:53:30 PM
wow,, I think I heard someone yell all the way down here in west by god "now burn up you sumbych"
that sure as hell will do it.. hope it works.
that sure as hell will do it.. hope it works.
Title: Bad ECM?
Post by: Haystack on March 17, 2015, 10:10:24 PM
Post by: Haystack on March 17, 2015, 10:10:24 PM
What's the black Mark on the trace right below?
Also, there is a difference in auto and manual computer wiring to the o2's. I don't remember exactly what it is though. Id check for correct orientation of the pins from the o2's plug to the corresponding pin on the computer plug to make sure the wiring is correct.
Also, there is a difference in auto and manual computer wiring to the o2's. I don't remember exactly what it is though. Id check for correct orientation of the pins from the o2's plug to the corresponding pin on the computer plug to make sure the wiring is correct.
Title: Bad ECM?
Post by: TurboCoupe50 on March 17, 2015, 11:08:04 PM
Post by: TurboCoupe50 on March 17, 2015, 11:08:04 PM
Quote from: Haystack;446267
What's the black Mark on the trace right below?
Also, there is a difference in auto and manual computer wiring to the o2's. I don't remember exactly what it is though. Id check for correct orientation of the pins from the o2's plug to the corresponding pin on the computer plug to make sure the wiring is correct.
Nope not so, o2 pin out is identical on stick or auto, MAF or SD... My o2 Wiring harness is from LSC Lincoln & I've swapped a A9P, A9L & C3W back and forth in my Bird & never had a issue... If o2 connector is pinned incorrectly(12v on signal return) or sensor shorted internally, that can damage ECM, as could a mis wired MAF meter...
The TAB & TAD solenoids are pinned differently between MAF & SD, are four extra wires for MAF meter and one for the fuel pump monitor but that's about it...
Title: Bad ECM?
Post by: FOX-XR7 on March 17, 2015, 11:13:21 PM
Post by: FOX-XR7 on March 17, 2015, 11:13:21 PM
Haha, yeah I hope it works. I Think perhaps that black mark is the reflection? I didn't suspect while looking at it closely. As far as the O2s, I know the difference in the loops between the auto and manual. But on my speed density harness, the loop off the manual harness goes nowhere. I'm still confused about it. I left it unplugged for now hoping it won't cause issues with the trace if it's unplugged. But I guess I need it to run the engine right. Haha, I just can't find a pin out for the 88 O2 engine Connector harness.
Title: Bad ECM?
Post by: FOX-XR7 on March 17, 2015, 11:19:13 PM
Post by: FOX-XR7 on March 17, 2015, 11:19:13 PM
I found this on a mustang forum. So I guess I just need to make sure that there is no voltage being looped back to the sig rtn.
Title: Bad ECM?
Post by: TurboCoupe50 on March 17, 2015, 11:50:08 PM
Post by: TurboCoupe50 on March 17, 2015, 11:50:08 PM
I checked Advance and same o2 sensor is listed for 5.0 in '88 T-Bird plus '87(SD) & '92(MAF) Stang, no doubt are wired same(plus I long ago verified the wiring when I did my swap)...
Title: Bad ECM?
Post by: Haystack on March 18, 2015, 12:02:32 AM
Post by: Haystack on March 18, 2015, 12:02:32 AM
There are four different plugs for 1986 cougars. I know because I had to order it for a 1987 to get the correct one. 1986 also didn't always have heated oxygen sensors.
Title: Bad ECM?
Post by: softtouch on March 18, 2015, 12:34:55 AM
Post by: softtouch on March 18, 2015, 12:34:55 AM
When you spliced the manual and AOD wires together at pin 30 this put 12v on pin 46. This is what blew out the land pattern in the EEC.
Take another look at post #29.
Take another look at post #29.
Title: Bad ECM?
Post by: FOX-XR7 on March 18, 2015, 12:52:22 AM
Post by: FOX-XR7 on March 18, 2015, 12:52:22 AM
Alright. So I needn't worry with the O2 then? Should there be no voltage on pin 46 at any point?
Title: Bad ECM?
Post by: FOX-XR7 on March 18, 2015, 12:59:59 AM
Post by: FOX-XR7 on March 18, 2015, 12:59:59 AM
I wonder now if I could even run my factory speed density O2 harness and not even have a problem. Since there would be no loop to worry about. Thoughts?
Title: Bad ECM?
Post by: Beau on March 18, 2015, 01:01:12 AM
Post by: Beau on March 18, 2015, 01:01:12 AM
I find it weird that on my Sport, there were two O2 connectors on the injector harness, and two more on the engine harness. I used the engine harness connectors, but had issues with the O2 sensors connected, so I shortly unhooked them and zip tied the connector ends up out of the way.
I've also read on Corral and a few other Mustang sites about there being differences in the AOD and T5 wiring for O2, and mismatching them will fry the EEC. I think T Moss even has something about it in one of his writeups.
I've also read on Corral and a few other Mustang sites about there being differences in the AOD and T5 wiring for O2, and mismatching them will fry the EEC. I think T Moss even has something about it in one of his writeups.
Title: Bad ECM?
Post by: jandmmustangs on March 18, 2015, 06:14:29 AM
Post by: jandmmustangs on March 18, 2015, 06:14:29 AM
Quote from: ThunderbirdSport302;446282
I find it weird that on my Sport, there were two O2 connectors on the injector harness, and two more on the engine harness. I used the engine harness connectors, but had issues with the O2 sensors connected, so I shortly unhooked them and zip tied the connector ends up out of the way.
I've also read on Corral and a few other Mustang sites about there being differences in the AOD and T5 wiring for O2, and mismatching them will fry the EEC. I think T Moss even has something about it in one of his writeups.
You are correct sir. The manual and automatic o2 harnesses are pinned differently. Mismatch them and poof goes the ECM.
Title: Bad ECM?
Post by: FOX-XR7 on March 18, 2015, 08:48:05 AM
Post by: FOX-XR7 on March 18, 2015, 08:48:05 AM
Quote from: ThunderbirdSport302;446282
I find it weird that on my Sport, there were two O2 connectors on the injector harness, and two more on the engine harness. I used the engine harness connectors, but had issues with the O2 sensors connected, so I shortly unhooked them and zip tied the connector ends up out of the way.
Very interesting. How did your bird run without them? I may try tying them up as well.
Title: Bad ECM?
Post by: softtouch on March 18, 2015, 10:59:26 AM
Post by: softtouch on March 18, 2015, 10:59:26 AM
Quote from: FOX-XR7;446279
Should there be no voltage on pin 46 at any point?
Don't know about the O2 stuff. I have to do some research on that. If the o2 heater circuit wires get crossed up with the sensor wires, I can see where that would blowup something in the EEC.
Edit: The 93 Mustang EVTM shows no difference in the O2 wiring between manual and AOD \transmission.
The O2 sensor EEC pins are the same as the 1988 Cougar.
Title: Bad ECM?
Post by: FOX-XR7 on March 18, 2015, 12:05:52 PM
Post by: FOX-XR7 on March 18, 2015, 12:05:52 PM
Well, I went over today, threw the computer in, and cranked it over. She fired up and idled for a bit. I noticed a coolant leak from the egr passage so I shut it off. She sounded a little rough, but I think that's because I need to adjust timing, fuel pressure and idle yet. More to come when I get that all setup.
Title: Bad ECM?
Post by: softtouch on March 18, 2015, 12:47:20 PM
Post by: softtouch on March 18, 2015, 12:47:20 PM
The 93 Mustang O2 harness is different than the 88 cougar.
The 88 uses one 8 pin connector C429
The 93 uses one 8 pin connector C101 and two 4 pin connectors C193 (left O2) and C1005 (right O2)
The wire colors are different between 88 and 93.
Looks like you will be connecting Stock harness C429 to Mustang harness C101. ( If your Mustang harness matches mine)
You will have to check that the wires match up right between the two.
I don't see why you cant use the stock 88 O2 harness.
The 88 uses one 8 pin connector C429
The 93 uses one 8 pin connector C101 and two 4 pin connectors C193 (left O2) and C1005 (right O2)
The wire colors are different between 88 and 93.
Looks like you will be connecting Stock harness C429 to Mustang harness C101. ( If your Mustang harness matches mine)
You will have to check that the wires match up right between the two.
I don't see why you cant use the stock 88 O2 harness.
Title: Bad ECM?
Post by: FOX-XR7 on March 18, 2015, 01:16:37 PM
Post by: FOX-XR7 on March 18, 2015, 01:16:37 PM
Alright. I'll throw my original back on. Because I know the mustang harness on my cougar eec engine harness didn't match up right before. But I'll check the wiring first. I can get back with colors of wires between the two when I get back over there.
Title: Bad ECM?
Post by: Beau on March 18, 2015, 01:25:34 PM
Post by: Beau on March 18, 2015, 01:25:34 PM
Maybe its a Mustang only thing, in regards to the O2 and the different harnesses.
In any case, it's something I need to concern myself with as my donor car was an AOD, the recipient car is T5 and will be using the donor car's engine, dash, and injector harness. Too cheap and far away from a tuner, or I'd simply have the O2 function bypassed at the EEC via a chip...
As for not running them, if you have catalytic converters, they'll eventually plug up as the lack of O2 inputs causes a bit of richness in the fuel/air mix. The previous owner cut the cats off of my Mountaineer and ran a custom dual exhaust...when i went to get it licensed the first time, the shop insisted there be a cat before they'd pass inspection on it, so they put one way downstream, almost by the back tire. Stupid-assed, I know, but at the time, I need the thing legal ASAP, so I agreed. Anyway, fast forward about 2 years, and late last summer, the son of a bitch plugged up as there's no O2's on the Mounty. I cut the tail pipe off and "unplugged" the cat, and had the pipe put back on. Now she has her power back and all, but now my manifold gasket(s) have a leak due to the increased pressure of the plugged cat from before.
I'd like to put the cats back on (the proper way), but all the ones in junkyards have had the cats torched off. Makes me want to smack the shiznit out of people.
Anyway, unless you can get a tuner to delete the O2 inputs and tune them out, I'd leave them in and functioning, as it will cut down a wee bit on fuel use...My mounty ought to get 15-18 MPG, I'm lucky to get 12 with a tail wind. 5.0, and a bunch of subs, amps, and some tools and gear in the back, too.
But yeah, enough of my hijack..sorry. ;)
In any case, it's something I need to concern myself with as my donor car was an AOD, the recipient car is T5 and will be using the donor car's engine, dash, and injector harness. Too cheap and far away from a tuner, or I'd simply have the O2 function bypassed at the EEC via a chip...
As for not running them, if you have catalytic converters, they'll eventually plug up as the lack of O2 inputs causes a bit of richness in the fuel/air mix. The previous owner cut the cats off of my Mountaineer and ran a custom dual exhaust...when i went to get it licensed the first time, the shop insisted there be a cat before they'd pass inspection on it, so they put one way downstream, almost by the back tire. Stupid-assed, I know, but at the time, I need the thing legal ASAP, so I agreed. Anyway, fast forward about 2 years, and late last summer, the son of a bitch plugged up as there's no O2's on the Mounty. I cut the tail pipe off and "unplugged" the cat, and had the pipe put back on. Now she has her power back and all, but now my manifold gasket(s) have a leak due to the increased pressure of the plugged cat from before.
I'd like to put the cats back on (the proper way), but all the ones in junkyards have had the cats torched off. Makes me want to smack the shiznit out of people.
Anyway, unless you can get a tuner to delete the O2 inputs and tune them out, I'd leave them in and functioning, as it will cut down a wee bit on fuel use...My mounty ought to get 15-18 MPG, I'm lucky to get 12 with a tail wind. 5.0, and a bunch of subs, amps, and some tools and gear in the back, too.
But yeah, enough of my hijack..sorry. ;)
Title: Bad ECM?
Post by: thunderjet302 on March 18, 2015, 01:31:52 PM
Post by: thunderjet302 on March 18, 2015, 01:31:52 PM
The O2 sensors are needed for adaptive learning and fuel trim. Don't delete them if you can help it. Especially since your car is not stock. It will run poorly with no O2 sensors connected.....
Title: Bad ECM?
Post by: Beau on March 18, 2015, 02:53:42 PM
Post by: Beau on March 18, 2015, 02:53:42 PM
^Indeed. I've got a catless BBK x pipe, and the FIRST thing I did when I took it out of the box was to put some used, but tested good O2's in it.
Funny thing is though, in my Mounty, despite the lack of O2 inputs, there's still no CEL. It does work...comes on every time I turn the key to on, with engine off...
Funny thing is though, in my Mounty, despite the lack of O2 inputs, there's still no CEL. It does work...comes on every time I turn the key to on, with engine off...
Title: Bad ECM?
Post by: FOX-XR7 on March 18, 2015, 06:24:04 PM
Post by: FOX-XR7 on March 18, 2015, 06:24:04 PM
Alright. I have a BBK off road H pipe. I got o2s pplugged into the bungs, just not plugged into the harness right now. Soo, I guess I'll throw my original automatic speed density o2 harness back in.
Title: Bad ECM?
Post by: Beau on March 18, 2015, 07:16:57 PM
Post by: Beau on March 18, 2015, 07:16:57 PM
FOX-XR7, this may be of some use to you:
http://forums.corral.net/forums/general-mustang-tech/1094179-oxygen-sensor-harnesses-manual-auto-differences-year-differences.html
http://forums.corral.net/forums/general-mustang-tech/1094179-oxygen-sensor-harnesses-manual-auto-differences-year-differences.html
Title: Bad ECM?
Post by: FOX-XR7 on March 19, 2015, 12:17:43 PM
Post by: FOX-XR7 on March 19, 2015, 12:17:43 PM
I found this link to an excerpt from another O2 discussion on corral. http://forums.corral.net/forums/11151822-post16.html This made me think more along the lines of putting the speed density harness back in because I am using the factory speed density eec harness. And like those diagrams between the 93 stang and 88 cat/bird from Softtouch, pins 43, and 29 are both utilized. So I'm thinking I'll be alright.
So I did go over today, fired her up, adjusted timing to 12 degrees btdc with spout connector out, and then adjusted fuel pressure to about 39 lbs. I shut the car off tightened down the dizzy hold down, plugged spout connector in, hooked up fpr vacuum line, and fired her up again. Computer was holding timing right around 12 degrees. After she warned up, idle came down to about 800 rpm or so. I shut her down. Let sit for 10 minutes or so, fired back up, let her idle a few minutes, then shut down again. I did this 3 or 4 times prolly, to make sure she'd start. then I tried to start and she just cranked. Didn't even try to fire. So I pulled the plug off the coil and layed a screwdriver across the shock tower to hover an inch over the coil terminal. I cranked and it sparked once, then nothing. Just cranking. No spark. I did still have fuel prime and pressure though. So I'm back to the drawing board when I get over there next.
As for the no check engine light, that's because I put the bulb in the spare bulb check engine light spot. So I put the bulb in the right side check engine light slot and now I have the light on all the time.so I'll pull codes again when I get over there next as well.
So I did go over today, fired her up, adjusted timing to 12 degrees btdc with spout connector out, and then adjusted fuel pressure to about 39 lbs. I shut the car off tightened down the dizzy hold down, plugged spout connector in, hooked up fpr vacuum line, and fired her up again. Computer was holding timing right around 12 degrees. After she warned up, idle came down to about 800 rpm or so. I shut her down. Let sit for 10 minutes or so, fired back up, let her idle a few minutes, then shut down again. I did this 3 or 4 times prolly, to make sure she'd start. then I tried to start and she just cranked. Didn't even try to fire. So I pulled the plug off the coil and layed a screwdriver across the shock tower to hover an inch over the coil terminal. I cranked and it sparked once, then nothing. Just cranking. No spark. I did still have fuel prime and pressure though. So I'm back to the drawing board when I get over there next.
As for the no check engine light, that's because I put the bulb in the spare bulb check engine light spot. So I put the bulb in the right side check engine light slot and now I have the light on all the time.so I'll pull codes again when I get over there next as well.
Title: Bad ECM?
Post by: jcassity on March 21, 2015, 07:59:29 AM
Post by: jcassity on March 21, 2015, 07:59:29 AM
Quote from: FOX-XR7;446342
So I'm back to the drawing board when I get over there next.
.
that repair only in my opinion should not have been so robust because you at this point would have wanted it to fail in the same location again,, ,as in encourage it to if it were going to fail.
the thinnest wire possible was better than the large jump.
I hope the eec broke again in the same spot if the eec is again bad.
this thread sucks for you but interesting either way,, good luck! keep up the good work to.
Title: Bad ECM?
Post by: FOX-XR7 on March 31, 2015, 05:19:54 PM
Post by: FOX-XR7 on March 31, 2015, 05:19:54 PM
Here's an update for everyone. I went over to the shop today, and I first put the original O2 sensor harness back on. Then I decided I would check codes. I performed a koeo test and got 2 codes. A code 24-ACT low, and code 95-Fuel Pump Circuit Problem. Then the continuous memory had 1 code. Code 11-system ok. I then tried to fire it up. It didn't work, just cranked. I was stumped. I stood there for a minute, got back in the car, this time, I realized I had forgotten to push the clutch in for the past few times since it wouldn't start. So I pushed the clutch to the floor and she fired right up. Haha, silly me. Hopefully all is well. Just need tires, windshield, inspection, and paint. Then I'm good to go. Thanks for the help guys.
Title: Bad ECM?
Post by: TurboCoupe50 on April 01, 2015, 10:35:06 AM
Post by: TurboCoupe50 on April 01, 2015, 10:35:06 AM
Quote from: FOX-XR7;446645
Here's an update for everyone. I went over to the shop today, and I first put the original O2 sensor harness back on. Then I decided I would check codes. I performed a koeo test and got 2 codes. A code 24-ACT low, and code 95-Fuel Pump Circuit Problem. Then the continuous memory had 1 code. Code 11-system ok. I then tried to fire it up. It didn't work, just cranked. I was stumped. I stood there for a minute, got back in the car, this time, I realized I had forgotten to push the clutch in for the past few times since it wouldn't start. So I pushed the clutch to the floor and she fired right up. Haha, silly me. Hopefully all is well. Just need tires, windshield, inspection, and paint. Then I'm good to go. Thanks for the help guys.
It cranks without depressing clutch but doesn't start?? Never heard of that one...
It's not supposed to crank unless clutch is pressed...
Title: Bad ECM?
Post by: FOX-XR7 on April 01, 2015, 12:30:17 PM
Post by: FOX-XR7 on April 01, 2015, 12:30:17 PM
Quote from: TurboCoupe50;446666
It cranks without depressing clutch but doesn't start?? Never heard of that one...
It's not supposed to crank unless clutch is pressed...
Title: Bad ECM?
Post by: jcassity on April 26, 2015, 08:04:33 AM
Post by: jcassity on April 26, 2015, 08:04:33 AM
so,, long story short,, because we are attempting this today.
specifically on the 1988 tbird stock harness..................(which is a unique animal).......
when going to mass air conversion, can we simply follow Eric's mass air write up? ,, which does not mention any warnings pertaining to 02 sensors or wiring issues?
specifically on the 1988 tbird stock harness..................(which is a unique animal).......
when going to mass air conversion, can we simply follow Eric's mass air write up? ,, which does not mention any warnings pertaining to 02 sensors or wiring issues?
Title: Bad ECM?
Post by: FOX-XR7 on April 26, 2015, 02:55:23 PM
Post by: FOX-XR7 on April 26, 2015, 02:55:23 PM
That is correct. No warnings with O2 harnesses. I can say I am currently using my stock 88 SD o2 harness with a mass air conversion and a mass air computer, and I don't have any o2 codes with engine off. Haven't checked codes with engine running yet. But so far so good.