Okay weird. Either I missed it the first time, or did it wrong, but I've got spark on the plugs. I've also got fuel.

So why doesn't it run? It cranks over but will not fire up and run.

Would a faulty ICM still provide spark but screw up the timing of the pulses enough that it isn't firing correctly?

Sadly, I don't know anyone else with a compatible ICM.

I'm really at a loss here, so unless I've blown valves or piston rings and don't have compression (which would be bizarre), I really have no idea now.

The car ran fine for 2 and a half weeks (after previous work: MAF replacement, thermostat replacement), then just started chugging on the way home one night, and the next day it would fire up and immediately stall. Did that twice, then wouldn't catch anymore at all.

If the timing chain jumped a couple of teeth, it could cause a problem like that, but that hasn't been an issue for several years. You may want to check and see if the injectors are getting the proper signal to fire. If they're not - it could be a PCM problem.

Ugh, I'm gonna have to drag this to the dealer it sounds like :(

Did you check for spark from all six wires?
You might want to pull the plugs & make sure they still look good.
How did you check for fuel & did you might want to recheck.
Does it ever sound like it'* trying to start?

Check - Spark on all six wires

Plugs are brand new, less than a month on them, NGK TR55 platinums

Wires are about a year old, pulled them all, no carbon tracking or arcs visible, all test well under 30k ohms resistance (about 0.4K ohms)

Fuel is good, pressure test at valve shows 45psi and doesn't drop

Cranks over, but not igniting the fuel.... so it sounds like the ignition pulse isn't going at the right time. It'* not backfiring, so the timing isn't 180 off at least...

I'd check the front 3 plugs even though they're new. Maybe you'll be able to tell if the fuels getting to the spark.

Edit - All the pink wires going to the injectors should have 12 volts with the key on. Anyone know if you can hook a voltmeter to the 2 injector wires & get a reading while cranking?

Well, fuel is getting to the chamber, but it'* obviously not sparking at the right time. Plugs keep getting fouled/wet with gas if I don't have the pedal in clear flood mode.

Cleaning the plugs doesn't do anything but set it up to get drenched again... something isn't right with whatever is telling the plugs to fire. According to how I read the FSM, it should be the crankshaft and/or camshaft sensor, with the signal being routed through the ICM. The PCM isn't supposed to take over till over 300RPM.

So that leaves me with timing chain jumped , either the crank or cam sensor dead/malfunctioning, or the ICM faulty? Correct?

With the crank sensor, or the ICM being bad, I'd expect that you wouldn't see any spark at all. I'm not 100% sure, but I think the computer would use "best guess" for the cam sensor if that was bad.

What you posted a bit earlier

Sounds just like when the MAF sensor went on my son'* '99 GP. However, often when we'd try to start it, it would sound like it wanted to at least. Same symptoms - good spark, wet plugs, won't start. I know you replaced it, but try disconnecting the MAF sensor and see what it does.

I would think that if you have a fairly fast responding analog meter, you may be able to follow the voltage readings at the injectors. If an oscilliscope is available (digital storage even better) the pulses should be easy to read.

That'* what the manual seems to say. If the 3X reference is missing, it should use the crankshaft 18X reference to do the timing

I'll try yanking the plug on the MAF... I seem to recall doing this before, but it'* worth another shot.

Thanks, I'll post back when I've tried it.

You didn't tell us about the wet plugs. Holding out on us are ya!

It sounds like the plugs have gotten soaked & cleaned multiple times. There'* a good chance this has ruined the plugs.

Really about all we know for sure is that it'* getting fuel. It seems to me that if you had fuel & spark that even with bad timing or jumped chain there would something happening. Wouldn't it be trying to start or backfiring through the intake or exhaust?

So I gotta believe we're still missing spark inside the combustion chamber. I wish the coil check would have worked. Can you borrow another meter from someone & is this the way you checked them? http://www.bonnevilleclub.com/forum/...e=article&k=33 Did you put the 'new?' coils on or just try to check the resistance?

Sorry for all the questions but we're missing something here. I would definitely try a new set of plugs before hauling it off to a dealer. It may have just been running super rich & permanently fouled the plugs. Besides the MAF a bad engine temperature sensor could cause it to run rich. I'll assume the air filter has been checked. If you decide to get new plugs then pull the old ones before you go so any excess gas can evaporate.