Hi all,

Day b/4 yesterday my daily driver camaro sputtered and stalled about a mile from my house and won't start again. I towed it home with my truck, and I am trying to fix it.

The car had been running fine (no hesitations), starting right up, no problems leading up to this. I have the service manual, and have been going down the list under chart A-3 'engine cranks but will not fire'.

1. Ive checked two wires for spark. Got spark on both while cranking.
2. injector fuses are fine.
3. I hear the fuel pump operate and my fuel pressure gauge climbs quickly to 41 when primed. It holds this pressure for a long time.
4. I checked my coil (original)/coil wire and the plug on the coil was severely corroded to the point that the plug no longer accepted the coil wire and I really thought that was my problem. I replaced the coil with a new one, and alas it did not fix the problem.
5. I pulled one of the easier spark plugs to get to, and the spark plug looked good.
6. Pulled maf sensor connector plug off, still no start.

I haven't checked the connections to the optispark yet as the connector is tough to get to, and wasn't sure if it was the problem.

Any help is greatly appreciated , at some point Im going to have to throw in the towel and take it in to be fixed, but I would rather fix it myself.

Can anyone help me out and give me some more things to check? Clogged injectors, fuel filter, etc.?

Thanks,

Tom

 

get a noid light and check your injector connectors to see if they are pulsing
also you know you need to run diagnostics, either TECH II, a scan tool, auto tap, LT1 Edit etc.. To see whats going on so you can fix it. If your getting the spark plugs to fire a good bright spark your opti should be good

 

Thanks kinslam, I'll check the injectors.

I have a scan tool, no codes were set. What specifically would I look for after results of a scan in this situation?

 

Another vote for checking the injectors. A motor needs 3 things to run: air, fuel, and spark (with correct timing). Unless it's hard to turn over, it sounds like you have 2 of the 3. Let us know what the injectors are doing.

 

Thanks, Ill check them right when I get home.

Thanks for the replies, they keep me motivated to keep trying :-).

 

Just to clarify... you can't use AutoTap to scan your OBD-I 94. And LT1_Edit won't scan, unless its the OBD-I version with pcmcomm scan software bundled with it. You can get free software like DataMaster or FreeScan, get a cable from AKM Electronics, and use a laptop to scan and data log.

Is the SES light on?

You replaced the coil because of corrosion - did you also replace the coil wire? Have you checked the Opti plug/coil terminals for corrosion? Take the time to check the Opti connector.

 

Thanks, I have the auto x-ray handheld that does read the obd1 codes and scans/monitors. And no, the ses light is not on, I also don't have any history codes stored. I kind of wish I did.

That's a good point, and I should check the coil wire. I guess I am looking for high resistance continuity? Say 1K-5K?

I will also check the plug/coil terminals for corrosion. The plug on the opti - seems really tough to get down in there to pull it off, any suggestions to make it simpler?

Thanks so much.

 

No auto store around me carries the noid lights. Some can order but will take a few days. Is there something special about a noid light? I have a test light (looks like a screw driver) that I put across the FI plug and cranked the engine but I couldn't tell if it was flashing it on and off too fast to see??

I also checked the resistance of each FI, they were all 12.2 ohms. The voltage applied at each FI plug is +12.7V.

I checked the coil wire for continuity and corrosion and seemed fine. I replaced the coil wire with a short plug wire I had laying around and the car still didn't start.

I got the voltage connector off the optispark and all the proper voltages were present with the key "on". The connector looks clean with no signs of corrosion.

Tomorrow I'm going to pull the fuel rail and check the spray of each injector.

What's next???

 

A noid light is basically a light bulb that works with a 12V DC source. The voltage applied shouldn't be constant. It should pulse. If it's holding a constant 12V on the FI's, then they are fully open.

 

That's a bit odd. You have fuel and spark but a no start condition. Any other prior repairs to the vehicle?

 

If he's just checking the pink wire at each harness connector, its going to have a constant +12V. The PCM provides the ground to fire.

 

Im dumb, I was clipped to a gnd on the manifold NOT on the FI plug. The pcm provides the +12V on one connection, and pulses gnd on the other right? So I properly connected the test light across the FI plug (checking that the light does in fact light if I force gnd) but it doesn't flash on and off when cranking! Ive only checked two FI plugs so far, Im going back out to check the rest.

If none of them pulse while cranking, what's the problem? Bad PCM gnd, injector drivers in the pcm? New pcm?

Thanks!

 

Damn, I learn something new everyday. Thanks for the clarification Injuneer.

 

Yeah, I can't get any FI plugs to flash the light. Im going to check PCM gnds.

 

The blk/wht pcm gnd wire in the starter area is broken! Bet that's the problem, Im off to fix it.