Strange problems with my GN, experts needed....

[Pats-GN]

Car chugs, backfires and dies after 15-20min of driving. I can leave my house and it will die in the exact same place everytime, about 15min of driving. It will fire back up but misses and chugs. Problem disappears when engine is cool. Changed the MAF, module, crank sensor, coil pack tests ok according to the meter. No codes on the scanmaster, getting fp at the rail, unplugging the cam sensor doesnt help. When it starts acting up AF stays at 6 and wont move just get backfires. Any help or ideas appreciated, tired of throwing parts at it.

thanks

 

[b231v6]

How is the positive battery cable look to the starter?

 

[Blown&Injected]

sounds like coil pack. it may ohm out ok and still be bad. check it after it heats up a bit.

 

[Pats-GN]

Battery cable to starter looks good, trying to round up another coilpack. Anyone else?

thanks

 

[Quick6'n'-K.C.]

if its heat related then i would think it would be the coil pack also-

also would check all your grounds and positive cables for corrosion and grease buildup=

hope you get it running better soon
BW

 

[1ARUNEM]

Don't know if I'll be out toward Jasper anytime soon, but if you're near Birmingham, I've got a spare you could try..

Goodluck..

 

[Pats-GN]

Thanks for the offer, but I took my old coilpack back to AutoZone and they gave me a new one under warranty so i'm going to try it. I'll let you guys know what happens.

pat

 

[ChrisCairns]

Remove your gas cap and leave it off ... see if it still dies in the exact same spot 15 minutes later.

 

[digorok]

Fuel pressure???

What is the fuel pressure when it dies???? Have you ever changed the fuel pump??? I've seen the sock get pluged up and do the same thing as your car.
Since you get no codes, it could be a fuel problem.

 

[Pats-GN]

I'll try the gas cap. I put a walbro 340 on it 2years ago. Fuel pressure was 42-43 with just the key on. I changed coilpacks today, didnt drive it far enough to see if it would quit but i'm still getting a steady miss at idle and on the road, and its getting worse, dont notice it under boost. Pulled the plugs, they look great, I was expecting one to be fouled if it was an ignition problem. BL's according to the scanmaster are 118 at idle and 113-115 steady 50mph. What should I look for next? Maybe drop the tank and check out the FP sock?

pat

 

[Intercooler]

Was this ever resolved?

 

[Pats-GN]

I havent driven the car in a couple weeks, but I did find something strange. Fuel pump relay on the pass. side fender has been hot and connectors are covered in black goo. Replaced the relay, just havent had time to mess with it. Also watched the FP, it raises a couple pounds when the car starts to miss. Strange.
I'll let you know what happens.

pat

 

[Blown&Injected]

since the fp goes up when the vac goes down and pressure goes up, th fp going up may be normal when the engine misses.

 

[49-blues]

check all the spark plug wires for cuts or shorts?

 

[Pats-GN]

Yes, wires are new.

 

[Intercooler]

This is going to be a tough one but now is maybe the time to check all your wires and connectors going to the MAF, IAC, etc.... I fixed a problem on mine today by doing this. I had a wire pulled out of my Translator plug so I had to solder it and reinstall. Check them good for cuts, pull-outs, fray, etc..!

 

[frankg]

If you have an EGR on it check that the solonoid is working proper. Unplug the vacumn line to the EGR and see if it still happens. Frank

 

[digorok]

MAF????

What kind/brand of MAF did you install???? If it was an aftermarket one take it back and get another. I've noticed that lots of aftermarket MAF's give lote of problems.
If you know someone with another TB that is running good, try swaping the MAF and see if the problem goes away.
What is the temp when it starts to miss???? Sounds like it could be heat related.
You might also check the conections to the computer and the grounds. Sometimes if you have a loose conection, it get hot and will disconnect.
I don't think your fuel system is the problem as the pressure goes up when the engine misses. It should do that. If the sock was plugging up the pressure would go down.
When it starts to miss, is it still in close loop????
Have you tried to just idle the car in the driveway to see if it would start to miss????
Check the conections to the spark control under the coil pack.
Have you checked for a trouble code????

 

[Pats-GN]

Thanks for all the help guys. I'm in the process of checking all the connections/wiring and ECM. I put an LS1 MAF and tranlator on it thinking that the problem was my stock MAF and I got no change at all, so I guess my stocker was good. Its definately heat related, it doesnt do it on cool nights, but in the heat of the day, it will stall in almost the exact same place. Not just a stall, but a total loss of power and eventually dies. Fires right back up, may do it 3 or 4 more times before I get it back home. No codes. Very aggravating. I'll post if I find out anything.

thanks
pat

 

[salvageV6]

Check your fuel delivery at this point with a remote gauge taped under the wiper if possible.

I'd also watch the cars voltage with a digital VOM hooked to the ECM or module power connections.