OK guys, I had another thread thinking that maybe it was the msd system but I took it out of the equation. I found a bad coil wire too. I replaced the coil wire and ignition module as well as put a stock coil on. The car is a 95 Z (OBD2) headers, cam of unknown specs but not very big, csi water pump, CAI, !maf(I cleaned it and checked it to be sure), and ported intake and possibly ported heads. The car has a 2 week old opti. The car belongs to another tech at work and since I have a little bit of experience on them they gave it to me. I have access to everything you can imagine at work (a Chevy dealership, I'm a tech there ) but this one has stumped me. Its saying its the high res signal. I've went through the trouble tree and I'm getting low voltage at the test connection as per the manual. The next thing it says is its either the pcm, bad connection or a wire going to ground. Anyone ever run into this? What I'm worried about is if I get a new pcm for the guy (we're going to warranty it so no cost to him cause he just bought the car from here 2 weeks ago) but if the car has a custom tune it may not run right. I know they'll cover the cost of the pcm but not the custom tuning. Everyone (well most everyone) gripes about the crappy service at the dealership. Heres your chance to help make a difference. TIA

 

why was the opti replaced 2 weeks ago?

btw that car is an OBD1. if you fear it has a custom tune then im sure you have the tools to pull the old program off of it... right?

 

If you voltage is out of wack, did you check the ign. module ground?? I had simular problem and cured it with a simple ground cleaning exercise, make sure the stud and all the wires on the stud are free of corrosion and scale. Just a thought.... hope it helps

 

Turbo Z, The opti was replaced by another tech that assumed that was the problem. It obviously didnt fix it so now I have it. The car is an OBD2 vehicle. There were a few of them put out then, but not many. Intrestingly enough, its also a 1LE car hardtop. I had a 94 bonneville in there last week that was OBD2 It threw me for a loop when I hooked the tech 2 up to it. As for the custom tune I may be able to do something to it but I'm not sure if it'll work or not. We're actually pretty limited in what we are and are not allowed to do both by rules and lack of some of the really cool aftermarket stuff that is out there, but GM wont let us use it. ie: LT1 edit



carnutz, I did check the ignition module ground and its fine. I even put a new module on it at the same time.


What I'm getting is a low voltage reading at the B terminal on the test connector. The test connector is the 4 wire connector located just above, and behind the MAP sensor. Its GMs fancy way of saying heres an easy to reach connection we put here just so you dont have to splice into the wiring harness to test voltage.

 

codes 36 and 42 are OBD1 codes. it has the later OBD2 style ALDL connector with the OBD1 PCM.

 

Youre right on that, What I 'think' was done was a OBD2-1 conversion but I cant be sure. The car was traded in 4 weeks ago and had all these mods done to it by the previous owner. Theres no telling what else I'm gonna find.

 

36 is distr ignition system[faulty coil paks to module
42[ignition control circuit check wires