IPrice

Ok, I've searched and searched the forum and found a couple threads that have kinda helped a bit. Even going back and retesting all my ignition components through Shoebox's OUTSTANDING website, I feel like my car is seriously posessed.

Here's the backstory. Sorry up front for the length, I just hate trying to help out if I don't have the whole story myself...here goes.

Bought it about 8 months ago. Ran ok, but check engine light was on and the trouble code was a random cylinder misfire. The previous owner stated that the fuel pump was getting ready to take a dump so I figured I'd go ahead and replace it since I had experience with it from my '95 and thought I'd like to start off right by bumping up to a 255 Walbro right away.

Even knowing that it wouldn't correct the issue, I replaced it.

The car still would stumble at times and so I began to troubleshoot per 'Box's site. Coil Checked good. ICM/PCM/ Opti all checked out.

Ran the car (even with minor misfires) for a few weeks until it began to die on me. Reading in to the typical Opti issues here, I parked the car and again, started to research the issue to remedy it.

I couldn't find any discrepancies with any of the values or readings. I then started the car and tried to get it to die out so that I could retest and attempt to catch the issue while it was happening. The car idled for 54 minutes before the CEL began to flash and misfiring. The car died out at 56 minutes and I couldn't restart so I figured it was time to investigate.

Again, all PCM/ICM/COIL/OPTI checked out. So, with all the crap I heard about the Opti beign the problem 80% of the time I went ahead and saved for a GM Opti.

The part came in so I immediately replaced it yesterday. I took my time doing it and did what I thought was my best to make sure and align the dowel pin ('96) in the correct slot. It looks like it can only go in one way but I don't want to assume so. First time I mounted it, the unit installed flush and went on great. Reassembled the rest of the car.

SO going to start it...nothing. Turns over great. Tested for spark by pulling the #3 plug wire and putting a screwdriver in it.

Got spark.

I thought that I could hear the FP priming. To make sure, I pulled the carpet above the pump, pulled the trap door removed the pump and checked the rubber hose from the new pump to the line. Looks good. No leaks. Reinstalled.

Here's the rub. I don't have a FP tester but I can smell what I think is fuel from the exhaust pipes when I crank it. HOWEVER.

I tried to push the schrader valve tip down to see if fuel would come out.

IT DOES not! tried to prime it a few times by cylcing the key on and off at 5 second intervals. And again, nothing is coming out of the schrader valve at the rear of the intake.

Maybe I'm not smelling fuel at the exhaust but I swear that I am. How is this true if I'm not getting pressure at the fuel rail??

SO, where do I go from here???

Sidenote, I do have an aftermarket alarm with a starter kill feature but I'm assuming that if there were an alarm issue it wouldn't even crank over since it's a starter kill type. ?? Just a thought.

All fuses check out under the relay cover and fuse box in cabin.

I seriously think that my '96 is possessed or jealous that I'm buying a new 2010.

Any other ideas or thoughts that any of you guys might have?

Thanks for the time and take care all,
Ivan

Kevin Blown 95 TA

What do your spark plugs look like? When it stalled after idling it for an hour, did you still have spark? If your coil or ICM is heating up and failing you can simulate that with a heat gun if you are careful (make it fail), or you can get some cold spray at an electronics store and use that to chill it back down again (make it work) to see if you have a heat related problem. Borrow a fuel gauge from someone or break down and buy one and take out the schrader valve and put the gauge on there to see if there are any issues since you seem to be worried about that. And check all the connections to the coil , ICM , and opti connectors. Check all your engine grounds while you are at it and make sure they are still there and in good shape. If you think your injectors are leaking all over the place, take the whole fuel rail off and use the service connector in the harness near the PCM to run the pump and see if they leak or hold pressure.

IPrice

Sounds like a good direction to start in Kev.

I need to pull a plug and see if I'm getting fuel there too. I actually started looking around my garage for a tool and found a new fuel pressure tester that I bought way back for my POS Notchback mustang. Its new but a Harbor Frieght tool ....err!! lol.

You mention taking the valve out before I test?? I've never dont' that before so ?? It needs to come out before I test for pressure?? I can do that.

Thanks,
Ivan

IPrice

DIG THIS...

Removed the coil from the car so that I can test it.

Its a 96 with 154k miles...looks to be the OE coil...lmao...

SO I test the resistance between the three terminals and the "secondary" (big terminal that plugs into OPTI).

I'M getting 5.8k Omhs at all three terminals to secondary. Maybe I should simulate heak soak with a hair dryer and retest???

Thanks!!
Ivan

Kevin Blown 95 TA

I only say that cause some tf the pressure testers dont depress the valve far enough to let pressure through so if you run into that problem, you can take out the valve core and do it that way. Good luck!

IPrice

Hair dryer test complete.

As I held the prongs on the terminals with the hair dryer going full blast...I noticed that the resistance was rising.

First off at room temp it was 5.8k Ohms. With the heat is steadily rised from that to 5.9...6.04...6.05...etc...this was in the first 30-60 seconds.

In 'Box's diagram it shows 8.0k Ohms. This is for a different style coil but should I be having more resistance than what I'm getting or is the perameter for a '96 different?

Thanks again guys,
Ivan

IPrice

Fuel pressure at crank shows 33psi......should be enough to start it.


BTW-Is there a way to test the ICM as well since I got it off the car and on my computer desk???


Thanks Kevin,
Ivan

IPrice

Well due to the enormous response I got from my topic, I went ahead and took the entire assembly to the local AZ.

They were able to test the ICM. Out of testing it 12 times, it passed all 12. He wanted to "make sure that it warmed up" so that it could give us some real results. ICM check SAT.

They couldn't test the coil there so I went ahead and bought a new one. I mean, everything else is pointing to it so I figured what the hell.

So after installing the new coil, still nothing. No codes, no SES light, nothing. I got fuel all up on the plugs and spark as well. Gotta be air that I'm not getting from incorrect timing from ??incorrect OPTI install??

Thoughts??

I'm gonna tackle it tomorrow when the sun comes back out.

Thanks,
Ivan

dStruct

Man, that's a good one.. Sounds to me like a fuel issue but it's too hard to say for sure, I was reading in the Fuel/Ignition section about some of the guys needing a check valve on their fuel line to keep pressure in the line, maybe when it sits for a while it just needs to be really really primed again with the check valve? Also 33psi sounds low I'm pretty sure it's supposed to be up over 40-45ish.

Have you checked to make sure the braided ground going from just under the ABS system to the ICM block isn't broken? My crimp on connector on the end of it was broken off and it caused some very random misfires for me until I fixed it.

I hate to ask the obvious but are you sure when you replaced the plug wires, they went back on in the correct order? That would explain why you have both fuel pressure, spark, but it wont fire up. Or maybe the Opti isn't aligned with the motor and the timing is way off?

Good luck!

IPrice

Great things that I should be second looking. I might be looking right over these basic thing and be trying to chase a ghost. I'll go out and take another look at the braided ground and also the plug wires. I did label em with some masking tape but my 17 yr old son did help put em back on...er...lol.

I swear that OPTI went on correct but, we are all human and I coulda gotten it wiggly and moved the opti around ...?

I'll check the basics like you mentioned before I go and rip the OPTI out again.

Man, sometimes we all just need a little "hey check the basics" talk to brign us back to earth.

Thanks,
Ivan