I bought a 93 lt1 (147,000 miles) at the end of last summer and since then I've had an intermittent dying issue that seems to be getting worse it used to almost die then run prefect after that. Now it fully dies and usually starts back up. Yesterday it was running fine I shut it off for about 10 minutes and it would crank but not start like it didn't even try to fire. I waited about 15 minutes tried it again and it sounded like it was firing a little but still wouldn't start. Another 15 minutes later it started right up. On my way home after about 2 miles it died and started right back up then ran fine.
This has only happened when it was up to temp and I can't seem to recreate this issue when I'm able to actually diagnose it. Fuel pressure seems to be fine but haven't been able to get it to act up while while I have a gauge connected.
Things I've done to it since I bought it: ignition control module, MSD coil, opti cap and rotor, fuel pressure regulator, plugs and wires, IAC, map sensor, and I have coolant temp sensors on order just because I guessing at this point.
Any help would be greatly appreciated it's finally starting to warm up here in michigan and I'd like to get this running right.

 

Welcome to the forums! Problems like this are the reasons some people drink! Intermittent issues are sometimes the worst issue to have. I`m curious about the fuel pump and pressure. If you have a way to hook up a fuel pressure gauge while your driving would be interesting. and maybe have a test light hooked at the fuel pump at the tank to see if it fluctuates while driving. If that's good you can eliminate that. Did replacing ignition parts make any difference at all? Is there any way the fuel line is close to a heat source? No check engine light? Any loose ground straps? Any loose wires anywhere? tight fuses, funny looking fuses? (shine a light through it, they can short out, look close) I think i`m ready for my third drink now! I hope I gave you a few Ideas. (There is always a reason) Good luck. Keep us informed

 

Thanks for advice. I hadn't thought about trying to keep the pressure gauge on while driving. I'll give that a shot when I get it all back together. I caved in and bought a MSD opti that I'm in the middle of putting in. The only CEL I've been getting is for an o2 sensor. No lights when or after it dies.
Replacing the ignition parts made a hell of a difference considering the car didnt run when i bought it lol.
And I tried shaking every wire I could hoping there was just a bad connection somewhere, even punched the ecu a few times but she just kept on running.

 

Welcome to the forum. I'm going to go with fuel pump also. I believe there is also a relay controlled by the oil pressure sensor that will shut the fuel pump down with a loss in oil pressure to prevent damage to the engine. If you want to just throw a part at it, that's easier than pulling the fuel pump and probably a lot cheaper.

 

I've heard about this oil pressure switch issue but I didn't know there was a relay involved. Do you happen to know where that relay is located?

 

Maybe it is just an oil pressure switch. It's been a while since I delved into that. A wiring diagram would tell you.

 

Thanks! I'll look into it!

 

Hey everyone, I have an update for anyone that cares. Finally got everything back together late last night and I don't want to sound too hopeful but from what I can tell she's running and starting fine at various temperatures. It'll probably be a little while before I can confidently say that the problem is fixed but so far so good!
I did both collant temp sensors and the MDS opti.
Thanks to everyone that shared their wisdom and ideas!

 

Great news. Hope that it is permanent. Do you think the parts you replaced were all bad?

 

well I'm not 100% sure. I had a S10 years ago that had similar issues running bad and not starting when warm and it turned out the be the temp sensor. So I probably should have thought of that before dropping the money on the opti but at least it gives me peace of mind that it's new and I hopefully won't have to worry about replacing that any time soon.