x Wild Bill x

So, car had been running great, took it out for a drive last Saturday, came home and parked it in the garage. Have been wanting to fix the A/C so I got some freon with dye in it. Head out to the garage to put freon in and go to start the car and it just turns over. I've been through this before so I started going through all the typical diagnostic procedures. I have it narrowed down to Pin D on the optispark harness not being grounded when the car is on. When the car is off, pin D reads .6 ohms, but when the key is turned to run, I end up with 1600 ohms or so (not the ~ 60 ohms I should have). I checked the wiring to the pcm and has 0.6 ohms also. Pulled the PCM and ohmed out the four PCM grounds, all are .6ohms or less. I also checked the grounding strap on the block, pcm and coil all are good. I'm thinking the PCM may be bad? However, I can hook my laptop up to the car and see the TPS go from 0% to 100%, oxygen sensors are reading, map has a value, car reads coolant temperature etc, when I turn the car over the rpm readings stay at 0....

Car is a 94 Lt1 6-speed, heads, cam, long tubes etc... Was originally tuned by PCM Forless and ran good.

Anyone have some advice or trouble shooting tips for me? I would greatly appreciate it.

Thanks,
Bill

97lt1camaro

iTrader: (3)

I'd check the PCM fuse in the fuse block by the door. I used to put a dead fuse in there as a theft deterrent

x Wild Bill x

I did check the fuse, but I will double check it and try a new fuse. Would I be able to read the VIN and get information if the fuse is bad?

Second thought/question. I also have a 95 LT1 Firebird Formula that is stock. Could I swap the PCM from that just to see if the 94 Camaro will fire? Only thing is the Firebird has an autotrans, will the car turn over without the neutral/park switch? I'm thinking it's the same as the clutch switch on the M6.

bufmatmuslepants

iTrader: (3)

You can do that to see if you get spark and fuel but I wouldn't run it long.

x Wild Bill x

That's my plan, hopefully I can try it tonight. As long as I hear it catch/fire I will know it's the PCM. Heck, I can even test the grounds and if that changes know it's probably the PCM.

x Wild Bill x

So I tried the known good PCM and the car still won't start so that rules that out. Also tried unplugging the MAF to see if that was corrupting the ground signal to the PCM, no dice. Not sure what to try next I think I just need to get a good ground/reference signal to the Opti so the computer can read the signals and fire...

x Wild Bill x

Figured I would give a final update for this thread. After trying new grounds to the PCM and engine there was no change in readings or the car running so I figured I would ignore the resistance readings and look elsewhere. I had an old opti that was removed due to intermittent failure, so I hooked it up and spun it by hand. Low and behold I had fuel and spark. So, got a new opti, installed it and car is running great! I just wish I could have figured it out sooner and enjoyed more of the summer weather with the car...

F0x Slaughter

http://www.mainstreamtopics.com/foru...rt-diagnostic/

Read

dually681

iTrader: (4)

its good to have a spare opti.
if i didnt have a fully built lt1.
the next time my opti went i would swap it for a 5.3 n turbo it.
but i have so much power out of thisone its not worth swapping yet...

im glad u got it sorted... great job..