If you haven't already, check the fuel pressure, injector pulses, and compression.

Edit - Also, one thing that I believe we have overlooked - have scanned for codes that may have been set?

Fuel pressure has been checked and is within normal ranges.

I don't have a injector test light :(

I'll see if I can dig up a compression gauge. Even if 1 cylinder lost compression, it should still start right? Just run poorly...I can't see losing compression on multiple cylinders at all once...


I'll check around for a PCM in the junkyard, last time I looked at the beginning of this saga, there really wasn't much to be had locally. According to the FSM, there looks like there is a Knock sensor to move over as well.

I should be able to pull a PCM from any other 96 Bonneville/Park Avenue/Eighty-eight correct?

At this point, I would agree with Ben. A PCM from a junkyard can be had for $35-$50 and is certainly worth a try. You may have to change out the PROM if the PCM is not from the same model and year, but that is pretty easy to do.

Check http://www.car-part.com for PCM compatibility

I thought I read here somewhere that you can use a 194 bulb with the wires bent out straight and plugged into the injector connector to check for power to the injectors. I'll do a search.

Thanks for that site link Bill. Very helpful, and hot damn, it works for Canada....

I know the injectors are firing, since fuel is getting to the chamber...it'* really just coming down to whether they are firing at the right time, or if they are just spewing fuel all the time, which would be a ECM problem correct?


(Thanks for all the help so far guys, really appreciate it. Any of you need regular computer (PC/Server) work, let me know, I'll be glad to help....)

Local yard is quoting me 125 for the ECM.

I've also been told from multiple people this is a flash based PCM and will need to be reprogrammed...I don't suppose the EEPROM chip is removable?

The reason for the compression check would be to check the status of the timing chain, although that is a long shot. I've used a 194 bulb as a noid light, and it works quite well. That will at least indicate if they are getting the signal to fire. I'm afraid that the computers of your generation are not my strong point.

Yes, you can use almost any kind of test light to see if the injectors are firing. As long as you can get a contact on each of the prongs, your light should pulse as the car is running (or cranking, in your case). The problem I'm suspecting is that the light will stay continuously on or off (I'm not sure whether the injector opens or closes with the application of voltage).

If the '96 PCM is similar to the '97, there should be a cover on the side of the unit with a couple screws holding it in place. If you remove this cover you'll see the KS module, which pulls right out. You will need to swap the module from your current PCM to any new PCM you intend to try so that the car knows the position of the crankshaft.

If the '96 is nothing like the '97, disregard the above paragraph

Additionally, I agree with Archon that it would behoove you to get the car scanned for codes. Many parts stores will loan a scantool at no cost, provided you put down a deposit.

Here'* something you can try when you put the plugs back in.
Turn the key to the run position to prime the fuel pump.
Pull the fuel pump relay & try to start.
Hopefully that will be enough gas to let the engine fire for a brief second but not enough to flood it.

We still need to determine if the problem is too much fuel or a weak spark. If the engine fires briefly during the above test then gets flooded when the relay is replaced I think the problem is most likely fuel related. If the engine doesn't fire at all I'd look for a junkyard ICM with coil packs.

I was doing some searching and I came across this thread where a fellow had similar symptoms that turned out to be an internal coolant leak. Not saying that'* your problem, but you might want to have a look.

http://www.bonnevilleclub.com/forum/...ic.php?t=50430