I'm located on long island NY and was wondering if anyone knows of a good place to bring my 95 z28 to because I have replace almost everything and my car still will not run and or stay running or start on a regular basis.... Opti spark 3 times, plug wires, plugs, I had aftermarket ignition system Delteq, replaced that back to stock coil and plug replaced plugs to opti spark and car still wont start or run on a regular basis... I brought it somewhere guy charged me 500 bucks and it ran good for like 3 weeks then started up ...so it is time to bring it somewhere thats good with lt1's please help...

 

Are u set on just taking it somewhere??? Or do u want to try to problem solve here?




Larry (Popo8) Co-owner
LTXtech.com

 

I don't see any mention of diagnosis of the fuel system. Have you checked fuel pressure?

 

yes i've diagnosed everything that i can think of I did noid lights, fuel pressure tester, compression test, fuses, relays, i scanned it with a snap on solus scanner... fuel pressures good compressions good all fueses are good relays are good fuel pump turns on stays on no codes no bad readings from sensors on the scanner... I've done everything in my power the car either cranks and cranks without firing over or it will start up fine or it will start up and run like **** depends on its mood that day

 

On the days it runs like crap....

Do you get ANY ses codes...and I dont just mean is the light coming on....but....scanning it, are their any.

Also...I may have missed it...bit I see you have thrown alot of parts at it...have you replaced the ICM?


Larry (Popo8) Co-owner
LTXtech.com

 

I just figured I'd take it somewhere because I've done everything I can think of unless you know of anything else i should check out before hand... it'd be greatly appreciated...

 

yeah i did the ICM as well when i reverted back to stock... and the only code that it throws up is my fan being open due to the thermostat but it goes away when it runs fine...

 

When you checked the fuel pressure was it during a time when it would only crank and not fire or was it only checked once when it was running fairly good?

We had a vehicle that had a fuel pump problem and would be fine then act up then be fine again for a while. This lasted about a week or two.

What was the pressure you saw?

Explain the code and fans being "open" and how you think that relates to the thermostat. And what about the thermostat?

What did the mechanic do? Is there a list of parts he supposedly changed? Was there anything electrical that he changed that may have been replaced with a cheap auto parts store version?

 

Where on Long Island are you located? What do you mean "fuel pump turns on stays on"? Have you looked at your plugs to see if they're fuel soaked? With the current ignition parts, are you getting good spark?

 

i checked the plugs they're fine I sometimes have spark sometimes don't... I'm located in suffolk county... the fuel pump turns on and it will stay going when i crank it so the pressure stays up... fuel pressure is around 40 psi if i remember correctly... I've checked it a couple times at both times when its running fine and when it wont start stays the same...the mechanic i brought it to said it was a part on the aftermarket ignition that he replace

 

Is there consistent spark out of the coil? Many auto parts stores can test the ICM, and possibly the coil.

Where in Suffolk County are you located? I'm in Selden.

 

Let's start with a "Signature" showing basic info about the car - year, model, engine, trans and any major mods. Not all years of the LT1 are the same. With a Signature, people don't have to go back to your first post to find the info buried there.

 

What brand of coil are you running. If it is MSD, swap it out for a oem one. Ask me how i know.

 

It honestly sounds like you have a computer problem, my buddy's car did this when he had a "PCM For Less" computer installed with a tune, it never did run right with it so he just went back to a stock computer. I would say somebody has messed with the tune on it man, try getting a new computer for it, you might be surprised. Good luck!

 

It's been said many times, many ways....it isn't likely to be the PCM. I think I've seen maybe 5...probably fewer....instances where the PCM had failed over the 11 years I've been on here.

Intermittant problems are very difficult to diagnose. You mentioned that the car was converted back from a delteq system. I'd recommend you focus on the ignition system as a source of the fault. What connections to the stock system were made to install the delteq then unmade to revert back to stock? Check every single connection. Check the harness to the opti as corrosion might be present.

Was the car running fine before the swap to the delteq? Did you do anything to the opti when you did the conversion like trim the rotor, etc?

I wouldn't take it somewhere just yet as the mechanic will likely end up doing a similar diagnostic...do it yourself and save.

Good luck,