ok. I have done the 5.8L swap and have the car running. I am having issues with the A9L/mass air swap. I did the pin swap and tapped the other wires. My problem is over fueling at idle flooding the engine to not restart. I adjusted my timing to 12 degrees BTDC. When I did that I shut down the car, tightened the distributer clamp, then tryed to restart. It would not start. Waited an hour then it restarted. So i tryed to adjust the tps and I found that all 3 wire to the tps were at 5 volts. I dissconnected the tps and checked voltage at the harness side. Orange wire was 5v, green was 4.88V and black/white was 0.05v. So in other words the car is thinking it is at full throttle when starting.
Anyone have trouble with this?
I am also haveing a hunting idle too..
Oh and with the tps unplugged I went on a road test and the car went really nice. Lots of power. This the tps plugged in I bogg and lose alot of power.
Thanks guys
. I should mention that my tab/tad/evap solinoids are dissconnected.
I was looking at the cool cats site on the mass air swap and it says I have to swap some wires in the harness for the tab/tad solinoids. I don't remember if I have done that. I will have to check tomorrow. Says that I could also have a MAP to BP incompatabillity. This is a box of worms.
I hate electrical. LOL
Fix the TPS problem, otherwise it'll never run correctly... It must have around .9 to 1v on the green wire at idle or you're just ' in the wind...
BTW a WOT condition shuts off the injectors(activates dechoke mode), so I doubt you have a flooding problem...
Don't worry about the MAP/BAP, I've never seen a problem using one for the other...
Your black/white wire (Signal Return) is not getting where it needs to go.
With the TPS disconnected you should have 5v between the orange/white wire and the black/white wire.
The Sig Rtn wire also goes to the ECT, ACT, MAP and EGR position sensors.
Sig Rtn goes to pin 46 on the SO EEC. Is this one of your repinners?
I had a huge flood problem. You could smell it when I was cranking to start from the exhaust. I pulled plugs and they were wet with fuel. It ran very rich too. It was just a crank problem. If you ran it then shut it off, then tryed to restart it flooded and would not run at all. But if I let it sit for 1/2 hour then foot to the floor while cranking, it started.
Well I saw that the Green/light green wire had 4.88 volts. I dissconnected it from the pcm and checked voltage on that wire on the main harness. It was zero. Then I plugged the tps back into the harness and I had 5v on orange and green wire. The green wire is still dissconected from the pcm. One of the guys checked the TPS and it was screwed. I have ordered a new sensor from Ford.
I went over all my repinning. The only thing I forgot to do was move two wires to the new location. But that was just for the tab/tad solinoids.
I still cannot communicate with the pcm yet. I think that the self test connector may need to be cleaned up. It is not corroded just old and guessing that it has never been scanned for codes in a long time.
I will keep you updated.
The only way you can get these readings is because there is no current flow through the TPS. You are reading the voltage through the TPS, so what you are missing is the ground (ie the Sig Rtn BK/W wire).
If you had your meter on the TPS side of the connector when you measured 5v on the BK/W wire then the connector could be bad.
Bottom line, the BK/W wire should be ground but is not connected to the chassis of the car, it goes to pin 46 of the EEC.
Check that the small "pig tail" wire on the negative battery cable is connected. This is the ground for the EEC electronics.
The BK/W Sig Rtn wire also goes to the test connector and a code reader will not work without it.
With the TPS connected see if you have 5v on the Sig Rtn wire at the test connector. If you do, that's your problem, it should be ground.
Well I checked signal wire to ground. Thats was good. I also isolated the signal return wire and checked continuity. It was less that an ohm. I have a friends A9L that i will try in my car and see if I can comunicate with it.
I don't know where else to start. This is the original 5.0L tbird harness modified to run mass air. The wires should be all good.
Checked it how?
With a volt meter?
With the TPS connected and the key on?
The result was 5V or 0V?
Did you check the pigtail wire on the negative battery cable?
I checked it to ground on the battery. It was open. I dissconected it from pin 46 (i think) and checked continuity on the signal return wire to the self test connector. Wire was .05 ohms. Then I went to the tps signal wire plugged in and dissconnected the signal return for the tps at the pcm. Ignition on i had 5v feeding back to the pcm by the signal return wire. I took the reading at the pcm connector. Then i dissconnected the tps at the connector and did an ohms reading on the signal wire to pcm. Less than a ohm. I am guessing the tps has shorted internally. I have one ordered and on its way.
I have also removed and cleaned all grounds within the cars body harness and engine harness.
Hi 86caprirs, you might be interested in my youtube video clip on checking the EEC4 TPS. It should give a better understanding of the voltages you should have. Just go to youtube and look up badshoeproductions
You checked for continuity from the BK/W wire on the TPS to the negative battery terminal and it is an open circuit?
If so, this is BAD.
Did you check that the little pigtail wire on the negative battery cable is connected?
This is GOOD.
This is GOOD.
It's normal to see the 5V feeding through the TPS on the sig rtn when the wire is disconnected from the PCM.
It is BAD if you see 5V on the sig rtn when the wire is connected to the PCM.
This is GOOD.
Bad guess. A new TPS is not going to fix this problem.
The ground for the PCM electronics is the little pigtail wire on the negative battery cable to pins 40 & 60 on the PCM.
I think if this ground is open, the PCM would not be able to pick the fuel pump relay. But it may be worth checking anyway.
If the PCM ground is good then the PCM is BAD.
Well the little wire to the battery is connected and also connected to the body. I checked the connector that is between the little wire and the body to make sure no corrosion is there. It was good.
When the pcm was in tact, I tested signal in the test BK/W wire connector too the battery, the ohms said open. No continuity. Then I isolated the circut and tested the wire. I am wondering about the pcm too. I have a good one to check with when I get to work monday.
When I removed the tps and checked the ohms, it was 500ohms off idle, 2500 ohms at 1/4 turn then open the rest of the sweep. Thats why I am replacing that part.
OK. I watched the video on the TPS setup. At rest the tps was 5.08v orange wire, 4.88v black wire and green wire was 4.88v. So almost 5v on all of them. I did a sweep test watching the green wire and no change at all.
did you disconnect the vacuum line from the map sensor and plug it?
if not do so
and i see in your profile your useing a C&L meter.. are you useing the right sampling tube for 24's if your useing the 19 pound one it will run real fat
Ok at the begining of the video clip I say to check continuity from the sig. return wire at the TPS to battery gnd. Did you do this and did you get a open. If so, pull the PCM's 60 pin connector and check continuity from the 46 pin (sig. return) of the harness to battery gnd. If it has continuity, you have a burnt out sig. return connection in the PCM. A tip here is to check continuty from the the sig. return wire at the self test connector to battery gnd. If it's good, it's likely good at the PCM which again means you have a bad PCM. A damaged PCM on pin 46 may be caused by a stick shift PCM hooked to an automatic EEC wire harness. The stick PCM's don't always have a diode in the pin 30 circuit to protect it during startup (which can short out the sig. return).
?? does the connection to the "body" look like stock factory wiring??
The EVTM doesn't show it that way but it could be wrong. Are there other wires on this "body" grounding point?
On the EVTM diagram C434 is your little one wire connector. Splice S533 should be on the "RH Fender Apr0n" and X goes to the ground side of the heaters on the HEGO's.
Blown::: Line is dissconnected. I am not sure about the sample tube as I bought the meter and 24lb injectors of a guy together. I suspect that it is right but I don't know what the sample tube should look like.
Badshoe:::: I tested signal to battery from the self test connector and got an got nothing. And this is a stick shift pcm to a Automatic harness. I will do the check to see if 60pin to 46 pin has continuity to ground. I make sure they are dissconnected from the pcm or do I just undo the pcm connector and touch one lead to the other on the ohms scale?
(((A damaged PCM on pin 46 may be caused by a stick shift PCM hooked to an automatic EEC wire harness. The stick PCM's don't always have a diode in the pin 30 circuit to protect it during startup (which can short out the sig. return))). This could be my no start condition. After it ran for 20 min or so, I shut it off and it would not restart for almost an hour.
Softtouch::: Yes the wire to the body is stock. It comes from the body harness to a single pin connector in a round black connector. It goes to the battery. Then from the battery to the body. We are talking about c434 right?
Any time the 60 pin harness is off the PCM or checking continuity, the key should be off but understand the harness pin 46 will be open to gnd. at this point. You should have continuity from harness pin 46 to the TPS sig. return wire as well as that wire on the Baro and EVP on the EGR if your still using it as well as the self test connector. When you plug the PCM back in, the sig. return wires at the TPS, Baro, EVP will now have continuity to battery gnd. because the pin is grounded internally in the PCM. Are you running a stick or an automatic? If you running a stick, the auto harness shouldn't be a concern as long as the pin 30 is left unhooked.
I am running a Auto.
Ok. I am sorta getting it. So pin 46 all attatched and plugged into the respected spots, should have continuity to battery? Or it will be open? I know I went self test to battery with key off and got nothing.
Sorry. I am terrible at electrical.
Yes, the BK/W wires coming from the TPS, EVP, Baro, ECT, ACT and the BK/W wire at the self test connector are all spliced together at splice S151 somewhere in the harness, therefore you should have continuity between all of those sensors on that wire. However, you will only have continuity to battery ground when the EEC connector is bolted to the PCM since it grounds to pins 40 and 60 inside the PCM. If there's no continuity to battery ground or pin 40 and 60, the PCM is bad. There's no self test with an open pin 46 as well.
A follow up to my last message is if you find there is an open in the PCM on pin 46, it's likely caused by using a stick PCM with an automatic tranny. In a stick car the pin 30 goes gnd. through the neutral switch and pin 46 when the tranny is in neutral. However, in an automatic car, pin 30 also is grounded in park and neutral but goes to 12 volts during startup (stick car does not). The PCM's for automatic cars are protected from this 12 volts internally but I understand many of the stick PCM's are not, causing a short circuit internally on startup in a swap like yours. So if you get another donor PCM for testing, it should be from an automatic car.
I know Ken knows his "stuff", but I'm running a early(has a '88 date code) '89 A9L stick PCM without issue...
The '86 Mustang EVTM shows a isolating diode externally connected to pin 30, so likely there would be issues if a '86 stick computer were used in a automatic application ... Unfortunately I don't have a later Mustang EVTM to check to see if there was one included in the harness in newer models...
I hooked up a good A9L and it all works now. So i have a bad pcm. Thanks for the help guys.