Hello all, first post here.

I just recently bought an 82 corvette. Ran like a champ for 250 miles home. Got into it yesterday to start cleaning the interior with the engine running and it sputtered and died. The car would start up again but ran very poorly and would die again about 10 seconds later. Took the air filters off and watched the injectors, come to find the passenger side injector is not spraying.

What I have done:
1) Checked both injector fuses, all fine
2) Tested for 12V on the injector plugs, both have 12v with key on.
3) Swapped the driver side injector plug onto the passenger side injector and it pulsed correctly. Not a mechanical issue.
4) Replaced a connector on the firewall on the passenger side that went to both injectors, 4 pin plug. Did not resolve the issue.
5) Ran a temporary wire from the ECM pin 468 to the ground wire on the passenger injector, no go.

After replacing the connectors (4), I did see the passenger injector running for about two seconds when the car started up, but it has not since worked. I do not hear a pulsing noise from this injector when the car is running either.

I even joined the two ecm injector wires together and this caused the car to run worse. The car would barely run and both injectors would barely inject fuel. This leads me to believe I have a fuel pressure issue.

The car will run with just one injector, but it runs rough. Sounds nice, but the idle is low at 500 and it shakes like crazy.

After performing all of these tests, I have come to the conclusion that I have a faulty ECM. No CEL codes, only got code 12. The installed ECM is a 5550 reman.

What are your opinions here?

Thanks everyone.

Edit: I took a look inside the ECM and was not able to find any solder joints that appeared incorrect or broken. Really hoping that I don't have to hunt down an ECM, be it an 6026 or something.

 

Well the only solution to a bad CFI ECM is to update to a newer ECM. I'm sure Buccaneer will chime in. If you're handy with a soldering iron maybe try replacing the injector driver transistor.

 

Would you happen to know where these transistors are on the ECM? I am capable of replacing these if I know which ones they are.

Thanks

 

Well it's those big flat black ones. Just traces it back from the pin 468. I'm not really a electronic guy, I've just have had good luck with replacing transistors in car radios back in the day when you could actually fix things and there was a Radio Shack on every corner. BTW congratulations on your car!

 

I would guess its the ECM. I have an 84 w/sAme engine and the ECM was toast,ran like a POS.Remember these are 1st gen computers equiv to early home computers running DOS

 

I traced the transistors back to the pins for both injectors and replaced them. Radioshack NTE291 NPN transistors. Still only one injector. I'll do some more testing with a test light tonight, but things aren't looking good. Really don't want to dump money on an ECM right now.

 

Updating the ECM is one of the best things that you can do for a CFI car.

 

hmm,
2 things jump at me

where were you cleaning and any chems?

mainly,, positive side of things,
cpu grounding inj needs good "amp/s"
you may measure vdc but resistance can drop volts to NOT enough
positive side

 

I think you nailed it here. I learned my lesson, use a test light. Turns out I was getting ground from the ECM. When measuring for hot on the injector, I got 12v, but when using the test light it barely lit up. Turns out there is a weak connection in the fuse box. I temporarily spliced both injector 12v wires together and it fired right up. USE A TEST LIGHT!!!!

Also, for future reference if anyone stumbles across this, I believe I replaced the transistors labeled Q13 and Q14. They were screwed down to the housing of the ECM.

 

 

Excellent,,,, Trouble shooting 101, whats the last thing that happened before things broke....

​​​​​​​60

 

To tidy this up, I was using some interior cleaner spray and wiping down the door when this issue occurred.

 

How does cleaning the door cause this??

 

​​​​​​​wth

 

Cleaning the door did not cause this, I was just responding to the question.

Thanks