Help! 1996 Grand Sport won't start...

[SkunkLT4]

Hey Guys,
I've got 1996 GS #344 and its been about 5yrs since the thing has run right. I bought it from my brother after he put an LT4 hotcam in it (it ran well for a few thousand miles) and needed something more economical to drive. The car has 34K miles on it and in finishing college up I never had the time to really dig into it until now.
The car is throwing a TPS code (P0122) but thats it. Its getting fuel as it comes out of the shrader valve at a pretty good tick. I know its not getting any spark, so my next plan of action this week when I get away from the office is to check the coil. If its not that I have to assume its the opti I would think. If thats the case this would be the 3rd one since the car was new.
The car was purchased from Roger's in Orlando by my brother in 2002 so its as mint as you can get on the outside and inside. However it looks pretty pathetic sitting in my garage next to my 1998 Camaro SS. I'd like to be out driving it.
Any other suggestions or past personal experiences that could point me in the right direction with this?

Thanks!

 

[Toms007]

I'd put a fuel pressure gauge on it to check for sure what you have. IIRC it needs at least 39psi, should be around 41-43psi normal. if it doesn't get enough pressure it won't fire the injectors.

 

[SkunkLT4]

I'd put a fuel pressure gauge on it to check for sure what you have. IIRC it needs at least 39psi, should be around 41-43psi normal. if it doesn't get enough pressure it won't fire the injectors.

Thanks for the info. I've got a friend bringing me a fuel pressure guage by the office this afternoon. If the pressure isn't whats required to fire the injectors, will that prevent the car from throwing a spark through some sort of system in the PCM?

I know my way around LSX's with my eyes closed. I just bought the GS because in the 8th grade I went to the assembly plant for the first time ever and saw the GS's rolling off the line. Then when I saw one on the emissions dyno getting put through its paces. I HAD to have one some day. So here I am. Haha.

 

[LT4man]

Your DTC PO122 (TPS) is where you should be looking.

No Diagnostic Trouble Codes ever set without a very good reason.

The Throttle Position Sensor is easy to check with a volt meter.

I do not have my Factory Service Manuals in front of me. Maybe someone can chime in with the voltage reading for the LT4.

SAVE THE !

 

[SkunkLT4]

Your DTC PO122 (TPS) is where you should be looking.

No Diagnostic Trouble Codes ever set without a very good reason.

The Throttle Position Sensor is easy to check with a volt meter.

I do not have my Factory Service Manuals in front of me. Maybe someone can chime in with the voltage reading for the LT4.

SAVE THE !

I actually have a set of the big red books for the LT4, so I'll give them a read tonight! Thanks for the reply!

 

[toptechx6]

In addition to the coil there is an ignition control module (ICM) bolted underneath it that can cause loss of spark. Since you have the FSM I would troubleshoot the TPS code, but if that does not help I believe a parts store should be able to test the ICM and coil, good luck.

 

[Hutch]

I agree with the suggestions everyone else has posted here. Run down that trouble code first, then go from there. Good idea to check the TPS, too.

While they aren't the most trouble free things in the world, 3 opti's in only 34K miles is unusual. If the previous units were in fact bad, something is causing them to fail prematurely. No water pump leak, I assume?

And hey... nothing is sadder than a lone skunk. Why don't you become a member of the Grand Sport Registry? We stinkers have to stick together!

 

[pkincy]

Definitely check the TPS, but it could also set that code if there is any short in that 5 volt (or is it mvolt) signal that is the reference signal for the TPS. I recall that there are about 3 circuits that use that same reference voltage source. I once bought a TPS when I really had a short at the AC pressure switch that was draining the reference voltage out of the TPS circuit.

Perry

 

[So Bay Vetter]

Was the ECM reprogrammed to accept the new cam?

A little left of center but, your opti should have ventelation lines running to and from the opti. If one or both were left off in previous repairs or it's suction is plugged, you could be getting contamination causing early opti failure.