I bought a 1990 camaro RS 3.1 when i bought it it ran strong but seemed to decline over the next few days now it wont start. I have change distributor, icm, wires, plugs, cap and rotor. i have it timed fuel pressure is good have spark, starter turns over. but i have no injector pulse.
Thinking its VATS the ECM, or possibly the PROM
any help is appreciated

 

Sorry I don't know anything about VATS (I don't have it, luckily)! I think though isn't a "security" light supposed to turn on the dashboard if VATS goes off? Why did you change all those parts, were you not getting spark, but now you are?

 

honestly i went off of what my friend said it quit on me once we did the rotor, cap wires and plugs the first time it quit on me. fixed the problem for a few hours did it again replace the icm it ran again then died the next day. took it to a mechanic friend of mine then he broke my distibutor. replace that. I put it in time as of right now it wants to run for 3 seconds max then quits does it a few times then refuses to fire up any more.

 

Did you put die-electric grease between the ICM and dizzy plate? If not you can burn it up,
check the ignition coil if it doesn't have spark, if it has spark and the timing is right, try replacing the fuel filter if its old, get a pressure tester and check the fuel line pressure, it should be 40-50 psi, most commonly its about 42 or 43...if it has good pressure, and a decent fuel filter, its probably the injectors, but it could also be the fuel pump..

 

put the grease one the icm, fuel pressure is 43psi. we were playing around with it compression check 125 psi. As far as we can tell the injectors are stuck open flooding the engine. anything we came up with lead back to the ecm. Any confirmation or ideas please

 

Hmm, probably need new injectors, check that the injector harness is plugged in at all leads, but I'm thinking bad injectors...ecm could maybe be it though, not sure, any codes?

 

we did check he harness yesterday there is power to each one but i just read that one shorted injector could mess up the whole thing the only code its shooting is 12 but not sure how much i trust anything on the car right now

 

Well, if they were stuck open, I don't think you would've gotten your 43 psi reading- it would've gone right to zero with the pump running if they were stuck. Is there gas in your oil (your dipstick would be overfilled, and your oil would smell really strong with gasoline)?

I looked back at your second message, you said:

Was the car running fine before you changed rotor/cap/wires/plugs? Or did it quit on you before you changed those things?

 

it ran fine before i turned the car off to go into the store for a few mins came back it just cranked didnt start. called him we got rotor cap wires and plugs started right up but what we didnt think of was the car sat for about a hour and a half. was able to start it one more when i tried to start it the next morning it wouldnt i replace the icm it once again ranfor another day again the next day went into a store wouldnt start waited for it to cool down started up drove not even a half a mile it quit and cant get it to start up if it does its only for 5 seconds max.

 

Yeah sounds like the ignition module was the original failure part. My only guess is to make sure the distributor's installed correctly (#1 TDC of compression stroke, not exhaust stroke) and re-do the timing, also make sure the firing order's correct (should be 1-2-3-4-5-6, and the #1 cylinder is frontmost passenger side on these engines). I guess it's possible you got a bad module too, see if you can find a store (like an Autozone) that can test the module for you.

Unless like you originally said, it could be VATS acting up. I guess none of us here have VATS (no responses), try asking (or searching) about VATS in the general tech forum instead.

 

Thanks ill retime it and go have the ecm tested in nothing comes up im just gonna strip the car and redo the entire drivetrain when i get the chance thanks for the help ill let you know if it works out.

 

ok ecu checked out nothing wrong prom is fine im done playing games with it so does anybody know a good im just gonna try a cheap swap anybody know a cheap t5 rebuild kit to hold a decent 350?

 

I've got the same problem with alotta the same symptoms. I'm frustrated! Mechanic can't seem to pinpoint the problem either. It has fuel, spark, new fuel filter, plugs, cap rotor, wires, ignition switch, good compression, ECU, etc. The injectors have the correct pulse, but they are dumping fuel.

I am inspired by "Vetruck's" camaro handling posts and would like to keep it a V6 to see if I can walk around some V8's too, but I'm losing patience and $$$ trying to find the problem...please advise!

 

thus the swap not gonna keep dumping money in a v6 if its not gonna get it running

 

You can't use that T5 with a V8... Without replacing the input shaft (spline count is different). And there is no such thing as a cheap V6 to V8 swap due to the parts involved (transmission, engine, engine mounts, front springs, harnesses, exhaust, etc).

You don't have a problem with the parts. It's the engine control harness. I myself and a couple on here have experienced this problem with intermittent stalling whenever it feels like with the 90-92 harness. GM issued a TSB regarding the ignition wiring.

 

Would that cause a high quantity of "fuel dump" into the cylinder via the injectors?

 

If the injector harness is shorted to ground ANYWHERE, the fuel injectors will continually be open, pushing fuel into the cylinders. The ignition wiring won't cause this, no, unless there is a short between an ignition ground wire and the injector harness.

Check the resistance between the blue and green wires in the injector harness (non-fuel rail side) and the body with the engine and key off and the ECM disconnected to avoid frying it. And also between the fuel rail side of the injection harness and ground at the same wires to make sure there isn't an injector shorting to its case (or anywhere else).

 

Thanks-will do and let everyone know the results!

 

i did have it running its been sitting for a few weeks and i had the ecm out for that period to get tested never bothered putting it back finally put the old ecm in this morning and she started right up. and come to think about it the last time we had her running was when we accidentally dropped the ecm in the floorboard i am able to start it on and off after the third or fourth restart it starts hesitating. think now i am gonna buy a new ecm and see what happends.

 

replace the ecm now its firing right up. now the fuel pump seems to be priming slow. currently thinking fuel pump and/or regulator first ill replace the filter see where that gets me.

 

I wouldn't worry about that.

 

whats your idea then?

 

So, in the end it needed 2 injectors. Now she's running like a champ!