I have power to all necessary ECM pins and good grounds. If I tap the signal wire from the distributor, the ECM will run the fuel pump but will not fire the injector or blink a noid light. I am only getting 1v across the INJ terminals when cranking. 9V on the red wire while cranking, which is plenty. Same voltage on blue during crank, because it isn't grounding. Checked on an '86 that runs, 9v during crank works fine. It's like the ECM can't supply enough ground to the INJ but it has good grounds
3 different ECMs. New injector. New module. It has strong spark and puts out a reference signal.
While cranking, I get no RPM data from WinALDL. So, I can manipulate the dizzy reference and get it to cycle the pump like it sees RPM, but it shows no RPM and won't pulse the injector. This ECM was pulled from a running '85 S-10.
[This message has been edited by Slammed (edited 05-10-2015).]
Ok, so I pulled the purple/white reference from the dizzy harness and tapped it to 12v. The ECM will command the fuel pump to run but no injector fire. So whatever is going on, cooked two ECMs injector circuit?
[This message has been edited by Slammed (edited 05-01-2015).]
The ECM and INJ share the same fuse. It is no longer popping after unplugging all the connectors and replacing, which would make me think it's completely fried a wire somewhere. But, the ECM has good voltage and grounds at all the right pins. What would cross that would cut the injector driver? TPS voltage too high does fuel cutout right? Winaldl shows good base on all sensors
The ECM grounds the blue wire to fire the injector. Because of the resistance of the injector, when the ECM is not firing the injector, you will read 12v on both sides of the injector. I know it sounds confusing.
Think of it this way. If instead the ECM instead supplied +12v to the injector, when the ECM wasn't firing the injector you would expect to read 0V on both sides of the injector right? So basically the same thing but reversed.
Does WinALDL show RPMs during cranking? If so yes you most likely have two bad ECMs. Sounds like your injector is shorted. That or the wiring to the injector is shorted. That short caused too much current to flow and blew the injector fuse. You replaced the injector fuse but the ECM is still bad. That's my guess.
Junk yards around here sell 80s ECMs for $20 if you pull them yourself. Not sure what other cars use the 84 ECM. In the Fiero the 84 ECM does not swap with any of the other ECMs.
When I first got the car, it already had a cooked capacitor on the IAC. Everything else worked, but the big red cap was burnt badly and the IAC did not function
Second one goes in and it's been totally fine til last night. Third one was from a running car that I had on the shelf. I have RPM on Winaldl
Fan is/was off both times it died. It also works fine. Looking at the diagram for the A/C I can't see where it would cause this type of failure
[This message has been edited by Slammed (edited 05-01-2015).]
In the Fiero the 84 ECM does not swap with any of the other ECMs.
Three weeks ago, I replaced the original ECM in my '84 with the surplus ECM from my '86. Except for telling me to upshift into 5th gear, it's working great.
Boyfriend just got home and told me there was smoke coming from the dash vents this morning on start up. I thought it smelled funny...
I'll go out and check for rpms on Winaldl. As far as no other ECMs working, I've interchanged 84-86 card type connector ECMs in the past
Any idea what the injector driver looks like on the board? I'm having a heck of a time tracing it back
The large cap is a varistor. It is used for over voltage protection. If you have lost it on more than one ECM, you have a problem with the charging system. What is the voltage output of the alternator?
There is also a possibility of a high A/C component on top of your DC. I know it sounds like I am making it up but it is real. To test - put your meter on AC and read across the battery terminal with the engine running.
A weak battery can exacerbate the AC output of an alterntor problem.
[This message has been edited by phonedawgz (edited 05-03-2015).]
Cleaned up all the grounds, checked all the fusible links, new ECU and still no injector fire. I am getting data again though
Voltage on the red injector wire is dropping down to 8.5v on crank. If I hook up the meter for voltage across the red and blue, I'm not even getting 2 volts. So I've got a major grounding/voltage issue. I just can't figure out where
If I tap ground to the blue wire, it'll pop the fuse
[This message has been edited by Slammed (edited 05-08-2015).]
I have power to all necessary ECM pins and good grounds. If I tap the signal wire from the distributor, the ECM will run the fuel pump but will not fire the injector or blink a noid light. I am only getting 1v across the INJ terminals when cranking. 9V on the red wire while cranking, which is plenty. Same voltage on blue during crank, because it isn't grounding. Checked on an '86 that runs, 9v during crank works fine. It's like the ECM can't supply enough ground to the INJ but it has good grounds
3 different ECMs. New injector. New module. It has strong spark and puts out a reference signal.
While cranking, I get no RPM data from WinALDL. So, I can manipulate the dizzy reference and get it to cycle the pump like it sees RPM, but it shows no RPM and won't pulse the injector. This ECM was pulled from a running '85 S-10.
[This message has been edited by Slammed (edited 05-10-2015).]
I hate blaming everything on the ICM, but it fails in so many odd ways. Recently I read an account of the spark being good, but one bank of injectors on a V6 not firing.....and it was fixed by replacing the ICM...
And don't forget....New parts are not necessarily good parts.
