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Topic: Bad ECM? (Read 20649 times) previous topic - next topic

Bad ECM?

Reply #30 –
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?
1988 Mercury cougar XR7- 302 bored .030 over, gt40p heads, F303, AlexsParts spring and seal kit, explorer upper and lower intake, 70mm tb, maf conversion, 75mm maf, fenderwell cai, 24 lb injectors, T5 conversion, bbk h pipe, Slp lm, 3.73 rear, 4 wheel disc conversion, 5 lug conversion. :D :D

Bad ECM?

Reply #31 –
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 never wired the FP monitor when I converted a 5.0 Stang to MAF, ran fine just set the code... Finally, to get rid of it I connected pin to a switched 12v, no code, no problem... all the EEC is looking for is 12v at switch on, it really has no idea if pump is running or not...

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...

Bad ECM?

Reply #32 –
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?
1988 Mercury cougar XR7- 302 bored .030 over, gt40p heads, F303, AlexsParts spring and seal kit, explorer upper and lower intake, 70mm tb, maf conversion, 75mm maf, fenderwell cai, 24 lb injectors, T5 conversion, bbk h pipe, Slp lm, 3.73 rear, 4 wheel disc conversion, 5 lug conversion. :D :D

Bad ECM?

Reply #33 –
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...

Bad ECM?

Reply #34 –
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.

Bad ECM?

Reply #35 –
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.
1988 Mercury cougar XR7- 302 bored .030 over, gt40p heads, F303, AlexsParts spring and seal kit, explorer upper and lower intake, 70mm tb, maf conversion, 75mm maf, fenderwell cai, 24 lb injectors, T5 conversion, bbk h pipe, Slp lm, 3.73 rear, 4 wheel disc conversion, 5 lug conversion. :D :D

Bad ECM?

Reply #36 –
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?
XXX
1988 Mercury cougar XR7- 302 bored .030 over, gt40p heads, F303, AlexsParts spring and seal kit, explorer upper and lower intake, 70mm tb, maf conversion, 75mm maf, fenderwell cai, 24 lb injectors, T5 conversion, bbk h pipe, Slp lm, 3.73 rear, 4 wheel disc conversion, 5 lug conversion. :D :D

Bad ECM?

Reply #37 –
Wire color?

Bad ECM?

Reply #38 –
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. ;)
1988 Mercury cougar XR7- 302 bored .030 over, gt40p heads, F303, AlexsParts spring and seal kit, explorer upper and lower intake, 70mm tb, maf conversion, 75mm maf, fenderwell cai, 24 lb injectors, T5 conversion, bbk h pipe, Slp lm, 3.73 rear, 4 wheel disc conversion, 5 lug conversion. :D :D

Bad ECM?

Reply #39 –
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.
1988 Mercury cougar XR7- 302 bored .030 over, gt40p heads, F303, AlexsParts spring and seal kit, explorer upper and lower intake, 70mm tb, maf conversion, 75mm maf, fenderwell cai, 24 lb injectors, T5 conversion, bbk h pipe, Slp lm, 3.73 rear, 4 wheel disc conversion, 5 lug conversion. :D :D

Bad ECM?

Reply #40 –
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
 

Bad ECM?

Reply #41 –
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...

Bad ECM?

Reply #42 –
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

Bad ECM?

Reply #43 –
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
1988 Mercury cougar XR7- 302 bored .030 over, gt40p heads, F303, AlexsParts spring and seal kit, explorer upper and lower intake, 70mm tb, maf conversion, 75mm maf, fenderwell cai, 24 lb injectors, T5 conversion, bbk h pipe, Slp lm, 3.73 rear, 4 wheel disc conversion, 5 lug conversion. :D :D

Bad ECM?

Reply #44 –
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
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.