Ignition problem?

[Stekman]

Hi guys. I've got a slight problem. Long story short, Lumina, 3100 motor. It will start fine, fuel pump primes fine, starts up - good hard crank. But it runs like crap. chug chug, chug chug, stutter, stalls out. Kind of like it's running out of fuel, except the tank is half full. Exhaust smells rich as can be, pretty much smells of unburnt fuel (#1 reason I am leaning towards ignition related). At first the motor ran a while, chugged for a bit before stalling. Now it pretty much starts, chugs once or twice then stalls. I don't want to start it again for fear of washing out the cylinder walls or doing any other form of damage. I'm on vacation and jhave to be back on Monday, so I have about 3 days to get this running with no access to actual diagnostic tools other than autotap and local parts stores and whatever them may have. I plan on pulling the ICM and having it tested, as well as buying another coil and replacing each with the new one until I go through all 3. Haven't done any diagnostics for lack of tools at the time of failure.

 

For the most part I'm an SBC guy, so my EFI experience is not that great, but I am mechanically inlined enough to draw conclusions and I say this seems like a failure in the ignition system: coil(s) or ICM.

 

My question is this: am I correct in my thinking or should I be looking elsewhere?

 

Thanks in advance.

[Andrew]

you are on the right track. sounds coil or icm related to me too. and of course keep your eyes and ears open for any possible vacuum leaks.

[Stekman]

Well, it would appear as if a new fuel pump is required. Nada on the fuel pressure gauge, not even a drip out of the rails. Got the car to stutter on starting fluid. Switched the AC Compressor relay out with the FP relay, same situation. I'm going to be hitting the wires with the multimeter to check voltage later today. I looked at a wiring diagram for some W body, not sure which, but it seems like I need 12v at the gray wire?

 

I'm still looking through other threads, but the tank seems (from what I've read so far, and from what I've seen), like a pretty straight forward process, straps, undo the lines, and lower the tank. I've got access to a lift and air, so that will help. Are the fuel lines the ones that require the special tool or do they just twist and disconnect? It's got a 1/4 tank right now and I think I have access to a trans/flat top jack. Any other tips or whatever would be appreciated.

 

Thanks

[rockfangd]

tanks arent too bad on ours. And it does sound like the pump.probe the red test wire on the driver side to the battery positive and test fuel pressure at the rail. no pressure bad pump