I have a '96 Z28 with a bunch of mods...but nothing too serious...yet. Anyways, ever since I had the FLP Longtube header package installed on my car in Oct 2001, I've had all sorts of problems with the SES light. Last year the light came on and the local shop told that the O2 sensors were burnt out and had to be changed. So I had them replaced, but that didn't fix the problem...so I changed the O2 simulators too. That also left the problem unresolved. Over the summer i had the fuel pressure tuned, and the car dynoed at SLP. THey were able to turn teh SES light off and get the car running like it was smoothly. Now the SES light has turned back on...and another local shop ran the diagnostics on it and told me it was the O2 sensors again. Now i'm not sure exactly what the problem is, because i checked the O2 sims and they are working...and i just had the O2 sensors replaced last year around this time, so they couldn't have gone bad already. I was thinking that maybe tuning the PCM will solve the problem. The LT1_edit program from carputing.com looks like it could help me, but I don't want to purchase it until i'm sure. If any of you guys can help, let me know. You help is appreciated...THANKS!

 

Exactly which O2 code is coming up?

 

The guy didn't specify, but he said that it might be because the O2 Sensor went bad. He deleted the error the first time, and said that if the light comes back on, the O2 Sensor might need to be replaced. He mentioned that sometimes the computer doesn't pick up a reading from the sensor and that it could trigger the SES light. The next day the light turned back on... That's really all I know, I'm a beginner at this kinda stuff.

 

There are a number of reasons an O2 can go bad...from physical damage, running leaded gas, burned wire harness, internal heater failure, bad head gasket introducing coolant into the exhaust stream...I think you see what I mean. Without more specific data, it's pretty much a crapshoot.

Your description leads me to believe that either the sensor harness was damaged during the header installation, or the sensor was not replaced with an OEM unit. Since headers typically move the O2 sensor away from the head, the sensor ends up working harder to maintain correct operating temperature, possibly leading to premature failure. A cheapo sensor might not be up to the task for long.

Try to get a more detailed explanation of the code being flashed.

 

If I go back to the shop and see if I can get the exact error code, will it help in diagnosing the problem? Are there others who have installed long tube, or other headers which required relocating the O2 Sensor and had similar problems such as premature failure of the O2 sensors?

 

The point is that not all "O2 sensor codes" are generated by faulty sensors.... could be wiring problems, ground problems, and a few other things.

In any case... get the exact code... it will be the letter "P" followed by 4-digits.....e.g. P0132. The exact code will tell you exactly which sensor, and what the PCM thinks the problem is... slow response, faulty heater circuit, open circuit, etc. Then we can suggest the cure.

And, the way to solve an SES light is to find the problem and cure it, before you decide to start "reprogramming" with LT1_Edit.... not a cheap "solution. On the other hand, if it turns out the SES light is related to other typical "long tube" problems, like the EGR code, programming might be an option. But find out EXACTLY why the light is on before you run out and dump $500 on an edit program.

 

I'm going down to the shop tomorrow to get the exact error code. I'll post it tomorrow when I have more info on it. I would rather not spend the $500 on reprogramming the computer if I don't have to yet...I was going to hold off on doing that until I had a stroker kit installed. Also, in my search to find more about reprogramming LT1 PCM's, www.madz28.com has a cheap option of disabling the rear O2 sensors. If the rear O2 sensors are the ones causing the problem...would this be a possible permanent solution? Do you guys know of any long term negative side effects of doing this?