1994 Camaro v8 auto. The way the problem was described to me was that the car would shut down at random and would sometimes restart and sometimes not. The driver of the car says he thinks the car only runs when the CEL is on.
I figured I was going to go over there and find a 5v ref wire shorting to ground, get paid and get out.
They tell me this car has had 5 optispark distributors and as many ignition control modules and coils! Supposedly Jegs is refusing to warranty another distributor assembly, so they bought a GM unit for $400.
It's also on it's 4th PCM. There's only a few feet of harness between the distributor and the PCM, I've opened the loom and wiggled the whole thing around to no avail.
Plus, as soon as I started working on it, I discovered the clamp was off the water pump bypass hose and the distributor took a nice coolant bath...
Great, now the plug wires I can't even see or reach are wet with coolant, this should help!
The way I understand it is that the PCM supplies 5v on the High Res and Low Res signal lines and the optispark distributor pulls them to ground. The PCM then commands the ICM to fire to coil based on that input.
42 EST grounded
36 High res pulse failure
16 Low res pulse failure
29 secondary injection pump circuit fault
18 injector circuit
66 a/c pressure switch
All the connectors look nice, don't think there's a pin fitment or corrosion issue on the PCM side or 4 pin distributor connector on the intake. There's a jumper connector for the distributor, guess the new unit isn't plug and play, kind of like those Delphi fuel tank units.
It USUALY fires after a long crank and will stay running pretty well, (until the wires got wet), then it starts breaking down and stalls. The last time it stalled on me it puffed a big cloud of smoke from the intake
I'm charging the Verus and will post my captures after I review them, but I wanted to get this up here before I forgot something. Maybe someone has an idea???
Got some ugly looking low res waveforms. There's one KOEO where I was looking at something else but still had the low ref wire backprobed. The signal was 0v, then there were 5v spikes, then it jumped up to steady 5v. When ohmed to Bat Neg with the sensor and PCM unplugged early on during the diag, I get no continuity.
Honestly, I think I'm just going to pass on this job, I've got more time into it than I wanted to have already and I hate working on Camaros. Everything is just too crowded and cramped.
I think the optispark is wiped out again, or there's some kind of internal contamination issue but this guy doesn't want to pull the trigger on #6. I don't blame him.