I have the car in my sig. I was in the gas and the car back fired ran like poop for 1/2 mile, then died. Wouldn't restart, discovered the coil died and had no spark. I replaced the coil have spark and it will not start. seems like it wants to backfire when I stop cranking it over. Also smells real rich out tails. Please help! Pulled one plug looked good not fouled.

 

I was not using nitrous and I don't have a timing retard yet. have a msd 6al which I did try to bypass no change.

 

do you have spark coming from opti? It seems your getting spark at coil wire now, but maybe a rotor problem?

 

I am getting spark at the spark plug.

 

Check fuel and compression. Those are the other 2 out of 3.

I had a bad ICM do something similar. There was some spark but very poor and at the wrong times. I would check that too.

 

seems to be plenty fuel and I have pulled 4 of the 8 plugs and they seem fine. will pull the other 4 soon. its a pain to do a compression test on these so thats my last resort. why would I have bad compression. I don't suspect any piston or ring damage as it wasn't smoking when it finally died

 

try using starter fluid.
if it starts then you're not getting enough fuel
if it doesn't start then it could be the opti

I'd also pull off the intake tube and check the MAF.

 

just tried that no go, kinda acted like it wanted to go a little. when I pulled the plugs they were wet and you can smell gas. that was before I tried starter fluid/

 

Did you pull any codes from the PCM? If it backfired & shut down then it should have some sort of fault code.

 

can I pull codes with a scanner if i can't start it? don't have one maybe autozone has one in their loaner program

 

when the car backfired it is posible it damaged the MAF , or created a large air leak from the throttle body to the maf,,, check the tube from t/b to maf, and try another maf( the maf is the same as any 4.8, 5.3, 6.0L silverado / GMC truck 1999 and newer)

 

Sounds like the screws let go on your rotor in the opti.

 

this is possible also, the opti was a brand new vented gm unit when i built the engine, but it always had a slight noise to it

 

I had the elbow off its a coated trickflow and I didn't see any thing inside, I will try a diferent maf the guy that has my old 97 will let me borrow it. I did for ****s check the fuel pressure 40 pounds. if the screws in the rotor let go would I still have spark at the plugs? I am gonna get a code scanner and see if there is anything there. Jay I replaced the opti with a new gm unit when I replaced the ignition box with the msd 6al and went with otvc msd wire kit. The only thing I didn't replace was the coil and that was on the list. (I hate being too late) This was all less than a year ago. The old opti is on the shelf and it seemed to have alot of play.

 

I also looked at the inside of the maf and no sign of damage