LT1 left me stramded today. Need some advice on what it could be ...

[LT1*FUN]

Sorry for the long post but I just thought I'd take a chance and see if anybody would be able to point me out in the right direction as far as diagnosing my 'Vette.

It's a '92 LT1 6 speed.

After getting back from work today, I got in my car, put the key in the ignition and tried starting it but it wouldn't turn over. The battery was clearly strong enough to crank the car so I knew that wasn't the issue. Within a few seconds, there was a really strong smell of fuel outside the car and I could see plumes of smoke coming out the tail pipe, though it was hard to see the exact color of it since it was very windy out and the smoke would just blow away really quickly.

After about 10 minutes of back and forth trying to start the car, it finally turned over and the idle smoothed out and settled down. A quick inspection under the hood revealed no obvious signs as to why the car didn't want to start so I got back in and headed home. I got maybe 3-4 blocks down the street and when I came to a stop at an intersection, the car died on me and never started back up again. Once more, there was a strong smell of fuel whenever I'd try and crank the car.

No need to go into too many boring details but about 1 hour and $100+ dollars later, the tow truck dropped me and the car off at home. After lowering the car, I got in and wouldn't you know it, she started right up again.


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Now, I'm pretty sure this next part is pretty important too, since I'm almost positive it's related to my car not starting today.

About two month's back, the car started to develop a bit of a "stumble" or "stutter" first thing in the morning. It would start up right away but after getting about 2-3 blocks from my home, it would stutter and sputter for about 4-5 seconds and then all was well. Car would run perfectly afterwords.

Over the upcoming weeks, the symptom gradually got worse. She'd still start up right away every morning, but after a few blocks of driving, the stuttering would return but stay on for 10-15 seconds then disappear again never to return until the next morning.

My first guess was that the problem was fuel related since the stuttering would happen just for a few seconds then disappear. It didn't make sense to me that it was ignition related, since (in my opinion anyways) if it was indeed ignition related, the problem would get progressively worse as the ignition components got hotter as the engine came up to operating temperature. I've had a lot of experience with opti-spark failures in the past with previous Fbodie's I've owned and when they start crapping out, it's usually at a specific RPM and when they reach that RPM (whatever it may be) the problem happens all the time at that specific RPM. There was no way around it.

This was something different.....

About two weeks back, I replaced the fuel filter (good thing too since the old one was completely clogged), purchased a set of Bosch III injectors from FIC. and the car already had new plugs, wires and ignition module only a few month's old. My fuel pump comes on when I turn the key to the start position and it's loud and clear so I don't htink the pump is the issues since its clearly coming on.

Could this possibly be my fuel pressure regulator? I pulled the vacume line off it to see if there was any fuel in it (thinking maybe the diaphram had worn out and burst) but there wasn't any fuel in the line. Could there still be another problem with the regulator? Could this possibly be ignition related?



UPDATE: Just looked for codes and none came up. Car continues to start right up the moment I turn the key. Can't take the chance though, so I'm not driving it again until I found out what went wrong. Don't want to be stranded again.

Thanks to all in advance.


- Phil

[Fastbird]

Sounds like a spark problem and not a fuel problem. Reason I say that is the smoke out the exhaust when extended cranking. That's most likely unburned fuel. Is the ICM suspect at all?? Does the Vette have a main ignition relay?

[LT1*FUN]

The ignition control module was replaced a few month's back with a new Delco unit from GM. I'd like to believe its still functioning properly so it's not too high up on my list of possible causes but I won't rule it out completely. Anything's possible.

I'm not too sure in regards to the main ignition relay or its wharabouts but I'll look it up in the book tomorrow. We'll see.

Do you think that the periodic stumble I've been experiencing the past two month's is related to what happened today? I think it does since right around the time the car stalled and died, was only about 3-4 blocks away from where I started. Pretty much the same distance I'd be able to travel before the "stumbling/stuttering" would start. Only this time of coarse, it didn't stumble but just died....

[Fastbird]

I wouldn't discount it yet.

[TrybalRage]

Opti, coil, coil wire. ICM even though it's new. That's what I'd look at first.

I had a coil wire that gave me all kinds of weirdness until I found it and replace it. Running until hot, random stalling, run smooth one minute and choppy the next. All over the board.

[crows93z]

probably ICM. they can get real hot since they're virtually mounted to the block. I've heard putting a shim/spacer in between the ICM and the block will help with cooling and lower the risk of catastrophic ICM failure and another $80 wasted on a new one.

[Cross]

This sounds a lot like what I am going through today.

Up in Phoenix for a weekend trip. The Dynaspark was just rebuilt I ahve been really easy on it but I got on the course and of course I had fun lol.

Well I had to play with the panhard a little and I thought I heard a whine coming from the rear. Well I go to turn into my buddies house and i had to make a U-Turn. I have been on The interstate the whole time, drove up here no problems its got good oil pressure and its under 160 the whole time.
Anyway I turn and notice it starts stumbling around 3-35k.... Then goes away. I pull up to his house and Rev it no problem. I am concerned but pop the hood and everything looks good.

I go to leave and I do not even make it a block. I tried going above 3k and it freaks out the Tach is jumping around like a Midget on Crack. Then it dies. I had that Optispark sinking feeling but she fired right back up but now its worse its hesitating, jumping all over then smoothing out then jumping it does not die but it tries to even just sitting there idling.

I pull into the corner strip mall and I turn it off, start it back up its still doing it but it starts right up... I am lost. I do not think its an Opti like before but I am at a loss. I do not have a code reader for the 95 around me and I know nothing around here so buddy to the rescue... I hope its just the ICM.

[joelster]

Make sure that the ignition is grounded properly. Attach another ground wire to it. If you go around a corner and the wire somehow loses connection the car can stumble until you straighten it out again. It is that flat-braided line coming form the driver side cylinder head. See if it is rusted.