92 lt1 stalling issue

[Martyn T.]

Hello all.
I bought this 92 lt1 6 speed car and drove it 3 weeks before it started acting up. 25,000 2 owner car.
first time issue car stalled while on the highway, started right back up. 1 week later car stalled would not restart. Flatbed to local station, next day mechanic said started right up, but it had an IAC code. Replaced it , he test drove a few miles ok.
Next day drove it 2 miles, died,let sit for 1/2 hour fired up and made it home 2 miles, died in driveway. Hooked up obd had ( i forget exact code think 36 ) but related to distributor. It would start for a few seconds,run lousy, tach went crazy and then die. Fuel pump runs. I smelled a hint of antifreeze, which I understand drips on opti.
Lead me to believe opti checked out. Had a more reputable shop replace with MSD dist, coil, wires, plugs, water pump, Delco icm. Now starts right up, drives great but stalls on occasion only at idle. No codes, shop says nothing shows on scope and will restart immediately sometimes with high idle.
Suspect the IAC that was installed ? the Engine coolant temp sensor ? defect in new MSD system ?
Any help appreciated !

[Joe L.]

Re: 92 lt1 stalling issue

Hello all.
I bought this 92 lt1 6 speed car and drove it 3 weeks before it started acting up. 25,000 2 owner car.
first time issue car stalled while on the highway, started right back up. 1 week later car stalled would not restart. Flatbed to local station, next day mechanic said started right up, but it had an IAC code. Replaced it , he test drove a few miles ok.
Next day drove it 2 miles, died,let sit for 1/2 hour fired up and made it home 2 miles, died in driveway. Hooked up obd had ( i forget exact code think 36 ) but related to distributor. It would start for a few seconds,run lousy, tach went crazy and then die. Fuel pump runs. I smelled a hint of antifreeze, which I understand drips on opti.
Lead me to believe opti checked out. Had a more reputable shop replace with MSD dist, coil, wires, plugs, water pump, Delco icm. Now starts right up, drives great but stalls on occasion only at idle. No codes, shop says nothing shows on scope and will restart immediately sometimes with high idle.
Suspect the IAC that was installed ? the Engine coolant temp sensor ? defect in new MSD system ?
Any help appreciated !

Martyn-----


What kind of IAC valve was installed? Was it a GM #17112193 or something else? If something else, that could be a problem.

Otherwise, your symptoms sound like the classical symptoms of an Opti-Spark problem, regardless of what code was originally set (OBD I system codes are not 100% reliable or specific). I have heard of problems with MSD units.

[Martyn T.]

Re: 92 lt1 stalling issue

Thanks Joe. I ordered the gm IAC and will hope for the best. After hearing about MSD units I'm sorry I didn't do more research before replacing the Opti. Could the coolant temp sensor affect idle ? I read a thread were malfunctioning thinking motor is cold could dump fuel and possibly stall it ?
Thanks again

[Joe L.]

Re: 92 lt1 stalling issue

Thanks Joe. I ordered the gm IAC and will hope for the best. After hearing about MSD units I'm sorry I didn't do more research before replacing the Opti. Could the coolant temp sensor affect idle ? I read a thread were malfunctioning thinking motor is cold could dump fuel and possibly stall it ?
Thanks again

Martyn------

I don't know if the coolant sensor could cause this problem but I kind of doubt it. However, it's pretty easy and inexpensive to replace it.

Unfortunately, there are not a lot of good options these days as far as a replacement Opti-Spark is concerned. Even GM only offers a remanufactured unit and it's very expensive at that.

[Edward J.]

Re: 92 lt1 stalling issue

Martyn, has the throttle body been cleaned? if not, clean the throttle opening and un-hook battery for a few minutes and shut of a/c and all electric run options and start car and let idle for a few minutes and then drive for to 10 minutes at different speeds. this may help,it will reset idle strategies.

[Frank K.]

Re: 92 lt1 stalling issue

Did they replace the water pump drive seal? If you replaced with MSD did they blue lotite rotor screws ? ( mine were not) How about the 4 pin connector going into the opt was it heat shrink or taped? A Gm replacement is expensive but all above is completed at factory. You can see the difference with GM replacement parts!

[Martyn T.]

Re: 92 lt1 stalling issue

ok, will try Delco IAC
Thanks again,
Marty

[Martyn T.]

Re: 92 lt1 stalling issue

Thanks , will try that also.
Marty

[Martyn T.]

Re: 92 lt1 stalling issue

I doubt they used lock tight on rotor screws. I take it it will loosen up ? I'll check the 4 pin.
Thanks
Marty

[Martyn T.]

Re: 92 lt1 stalling issue

Thanks for your help. They finally got it to stall while on the scope, called MSD and they confirmed a defective distributor ( very rare was there response) and sent a replacement, so the shop got to do it again. Runs flawless for now anyway
Amazing the rust inside the original 25K distributor where a lack of use is worse than overuse sometimes.
Next is clicking when taking off 6 speed manual left rear wheel. I'm guessing u joints are dried up ?
Thanks,
Marty

[Frank K.]

Re: 92 lt1 stalling issue

Clinking in rear could be any thing (brakes) I would run it a higher speed and see if it increases,if not give it a few short trips and see if it clears. Good Luck!