lifbcracker

So i've been trying to diagnose whats wrong with my car, its been down for a month now. It all started when I came home from work and I spun through some sprinklers all of a sudden my car started backfiring and if I gave it gas i got nothing, it coasted to a stop and wouldnt start back up. The car ran fine before that. So far i've tested to see if the injectors are working and the spark from the spark plugs/coil. Both are getting spark and my injectors prime everytime. I've tried new plugs and new coil and both didn't work. I've been waiting for a friend to bring a tech2 but he's been busy. Im not sure what else to do, I tried to do what shoebox says to test the opti, but i didnt have a digital voltmeter - just a ghetto one.

Correct me if im wrong (im not sure exactly how the opti works) but if the opti were the cause I wouldn't be getting spark at the coil or plugs would I? Even with a spark plug in the boot and a crank of the engine I get plenty of spark but it wont turn over, all i get is a couple sputters like it wants to start but no fire. I've checked all fuses and relays.

What else can I try or do without a scanner?

dre2013

i believe you'd still get spark, but it just wouldnt be too strong..thats what happend when we tested an opti that was going out

Sweetred95ta

With the spark plug out, did you verify that the plug was sparking as the cylinder was at TDC? This would be the point when the open cylinder is finished letting all the compression out of the spark plug hole.

How have you verified this? Have you checked (with a Noid light) to see if they are pulsing as the car is cranking? How does your fuel pressure look?

lifbcracker

Exactly how am I supposed to tell when the motor is TDC when its cranking over? I pulled the plug out and cranked the engine over and got spark through the sparkplug over the electrode. I also tested 3 other cylinders.

I checked the injectors with a noid light and they were pulsing as it was cranking. I havent checked FP with a guage but I just got done getting my 383 tuned and have never had FP problems - if anything, my FP would be high - its been tuned down pretty far.

I've only put maybe 8,000 miles on this engine. I replaced practically everything except the opti, rear end, and tranny.

Sweetred95ta

If you only test one cylinder at a time, you will hear the compression escaping out of the spark plug hole as the piston is coming up on the compressin stroke.

Just because you haven't had FP problems, doesn't mean you shouldn't check it. FYI, you can't tune FP; you can't adjust it unless you have an afpr. If it's cranking and sputtering, sounds like a fuel problem. That's why I asked.

lifbcracker

I have an aeromotive FPR and its been adjusted accordingly. This sputtering i speak off is not even remotely sounding like the car is wanting to start, more like the motion of the crank fliping over once or twice. Why would my car backfire before it died if I was loosing FP? The car ran perfect up until that momment.

lifbcracker

any more ideas?

Sweetred95ta

Check all of your fuses and grounds (especially the PCM ground, which is located on the passanger side of the oil pan).

lifbcracker

still doesnt seem to be the issue

Injuneer

Are you aware the Aeromotive AFPR's are notorius for short lives and incorrect fuel pressure, and have been for the last 4 or 5 years?

lifbcracker

i have heard some stories - to be quite honest I havent checked my FP, but im taking it to NLP wed. - i dont have the time to mess around with it.