What am I missing here?

[Pats-GN]

I'm beginning to wonder if i'll ever get this thing reliable again. GN runs great for 30min or so then it misses hard, backfires, loses power and dies. Fires right backup, but if you want to get home you have to let it cool down then its ok, which is making it extremely hard to find the problem. Car seems to have good fuel pressure at all times. No codes. Thought the problem was a wells coilpack, replaced with a new delco coilpack/module, no luck. Have also changed MAF, ECM, crank sensor, cam sensor cap, chip. I dont know what else to look for. I would assume i'm loosing fire since the car backfires so badly. What am I missing? Thanks in advance

pat

 

[topfuel]

Try cleaning and tightening the ground wires on the back side of the
cylinder head. Good luck...

 

[Paul Clark]

Any chance you have a wire (to something) someplace that sags a bit when it gets hot and shorts out - then it "recovers" after it cools off?
Paul

 

[acoen]

I have a friend who had similar problems. Drive for a while, loose power, miss then die. Wait a few minutes drive for a while loose power, miss then die. Pregressively gets worse and worse. Ended up being is Catylatic Converter was plugged solid. Once it cooled down it would run great until it heated up. But with your aftermarket exhaust you may not have a cat installed. Just a thought.

If this is not your problem, check those grounds at the back of your heads. I don't have a wiring diagram in front of me but I think one of those grounds your ECM.

 

[GN owner]

Check your temp sensor. It's possible that it is defective and is affecting your air/fuel ratio. Also possible you have a heat sensitive electrical component like the MAF sensor.

Hope that helps.

 

[Pats-GN]

Thanks for the replies, I upgraded to an LS1 MAF and translator recently and it didnt help. Guess i'll take a look at the grounds tommorow. I'll let you know if I find anything.

pat

 

[Turbo Indian]

I've had the same problem, only to lear it was the fuel pump. it dosen't matter how old it is they can go bad in 10 min. of run time.

 

[Pats-GN]

I have good fuel pressure when it happens, and the backfires lead me to believe its not the pump, but I could be wrong.

 

[Dwayne]

Had this happen to a friend a few years back, turned out the the "hot" wire off the battery for the ecm was sagging and getting too close to the header and cutting out....good luck

 

[Joe Tiano]

you might also take a look at the batt+ wire ...down at the starter and the fuseable links that are connected at the same place...Ive seen more than a few problems there! hope this helps joe

 

[Pats-GN]

Checked out the battery cables and grounds today, nothing seems to be out of the ordinary except the cable that runs under the pass side header to the block. The heat shield is loose and could have frayed the cable but I didnt have time to see for sure. Also, took a look at the crank sensor, the blades on the balancer that run through the sensor are bare metal, evidently its rubbing the sensor at some point because the paint is gone. I assume this is not normal, but dont know if it would cause my stalling condition. What do you guys think?

thanks
pat