My Dad recently bought a 1990 Corvette (I know not a f-body) but the Corvette forums have been worthless so I figured I would try over here, these forums were always very good to me back when I owned my 92 Camaro

Anyways here is the deal. The car will start and run, has a bit of an idle surge but nothing too crazy, we did replace the IAC and ECT sensors and it seemed to help a bit but not completely. However once the car runs for awhile or you drive it and shut it off the car will not fire back up. You have to leave the car sit for a period of time before it will start up again?

Also here is the weird part, the car has spark, and there is fuel pressure at the rail but it just appears the injectors are not "firing"... however if you spray starting fluid in the TB the car will start right up and run normal?

We are absolutely clueless at this point so any help would be greatly appreciated! Thanks ahead for the help

 

sounds like the ignition module needs to be replaced..... on my car which is a tpi just like yours is behind the dizzy.. its black and should have two plug ins wired to it.. when the car heats up and when i was driving around the car would shut off and would have to sit and cool before it would start back up again... replace that and report back.... make sure it has enough grease also.. sometimes there isnt enough and would cause it to act up...

 

Thanks for the advice, ignition control module is something I have kind of heard here and there so I think it's probably worth just getting a new one and trying at this point. Would this cause the injectors to not fire for some reason? I really do not know much about electronics systems when it comes to these cars and what does or does not affect certain things. Thanks again!

 

it has everybit to do with ignition spark of the spark plugs... that module affects the cars starting.... if the module is acting up the car will have a hard time starting when hot and the injectors will not fire if the car isnt running...that control module should have silicone grease in it... sometimes when there isnt enough it acts up and once its heated up the cars shuts off until it is cooled again.... i bet you that will solve your issues of shutting of and waiting to cool down part....

 

We were able to grab a new ICM last night and installed it in the car and unfortunately there was no change at all The car still start up and runs fine, once it warms up the car stays running fine but when the computer goes into closed loop it does seem to run a bit rougher. Once you turn the car off and try to start it up again it will just crank and not start. If you wait for awhile (maybe 10-15min) and try it again the car will usually start and do the same thing again.

At this point I am completely lost, could a bad ECU be doing this? It just seems to me like something is not "firing" the injectors because there is fuel pressure at the rail and spark.

 

I had this exact same issue when i did my tpi swap.
It was the injectors. I tried using the originals that came with the tpi i got and this would happen after it warmed up enough to go into closed loop.
I changed them and problem solved. Mind you i also put slighty large ones in to handle future planned upgrades.

 

Injectors and ECU are where i'm at right now, it's either the injectors themselves not working or the ECU which should cause them to fire.

Anyone know of any injectors that will work in the car? I've heard there are a few that crossover but i've been out of the TPI loop for quite awhile.

Thanks again for the help guys very much appreciated!

 

are your injectors the stock original?

 

Yes the injectors are the original stock ones in the car.

 

might be injectors then. my originals lasted 4 years 24,000 miles.

 

Could be the injectors, maybe not. ohm them hot and cold. The OEM injectors have a habit of shorting out when hot. Worth a try.

Sounds like a leaking injector or 2...

 

second the reply by JustCruzin, mine would crank fire once or just a half and then just turn over, no spark?? nope, plenty of spark, there was one shorted inj. One bad inj. will kill all four on that side. They are hooked up in a parallel circuit and the dead one(shorted) sucks up all the current for the circuit on that side and the others won't fire until the shorted one is removed from the circuit. Find the bad one and it will start and run but not too smooth, had to drive mine back to the garage on 7, wasn't fun but made it.

 

on mine all the injectors ohm'ed out just fine and they worked just fine but just didn't have
the umph anymore to run the car when in closed loop.

 

Check the resistance of the injectors should read around 15-16ohms.
Remember to check them cold and also when engine is hot,not unusual that they are ok cold but when warm not ok on the same injector might very well be your issue.

regards

 

How exactly do you test the injectors? I have never been great when it comes to electrical stuff. I have a multi-meter so will this work?

 

Yes it will work perfectly,remove the hat and messure on the 2 spikes on the injector.