hi guys its been awhile...heres my dilema..87 gn...had the wirng cleaned up on the car..got it back to factory..(ie removed alarm stereo stuff etc) new ac delco coil/module, new chip, new air meter, new trans, exhaust etc..this is the problem after driving the car for about an hour or more..it starts stumbling/cutting out under load..car runs great when cold and up to temp driving for about an hour..it runs good beyond that in the cooler weather...yesterday it was 85 or so..drove 30 mins on the highway..then shut off for 25..then 15 then off..then 20 mins of traffic..then another 20 on the highway then it staarted its "thing"..once up to speed it seemed ok just light to medium accelaration..after another 15 min.s to get home (highway)..i was able to get it to miss when just lightly reving to 3k..let it kool for s..then another 40 min higway and traffic fine..sat for 30 then 20 min. of traffic..then it started again!!..got worse the closer to home....so just wondering if anyon has been here before?..just looking for ideas..i def. feel its heat related?..ideas..thanks guys!
hot soak problem?
- Thread starter Madmaxx87
- Start date
- Joined
- Feb 18, 2006
Could be bad cam or crank sensor. Have you ever replaced them?
When it starts to act up unplug the cam sensor while engine is running. Go for a ride and see if anything changes.
When it starts to act up unplug the cam sensor while engine is running. Go for a ride and see if anything changes.
I have been fighting that problem for 5 years. The list of possible causes have been replaced, some twice, with no luck. Im about to put a new cam in it shortly. It would usually start stumbling after being fully warmed up, and for a few minutes I would actually think I had the problem fixed. Replaced LS1 MAF, coil pack, ignition module, 10mm plugs, plug wires, all vacuum hoses, all silicone connectors and spices, had turbo rebuilt, bypassed factory boost actuator with manual boost adjust, new radiator, new head gaskets ( which were blown anyway), new caspers cam sensor cap, new crank sensor, fuel pump with sending unit, fuel filter, all new fuel lines, cleaned out intercooler, replaced throttle body rubber seals, compression check was okay, and more. Heck, a worn cam is the only other option I have at this point.
holy crap!..thanks for sharing..i would like to say i feel better but i dont ..lol...i have verifed i have a new fuel pump..crank sensor could be in my near future..i changed plugs..but havent driven it long enough yet to know anything..new wires are on the way..this happens after driving 45- 60 min,s on a warmer day..cooler days it wont do it...i'm not liking this!..lol
- Joined
- Feb 18, 2006
Not a Caspers L.E.D. cap?
Did you try what I suggested?
Rick
Did you try what I suggested?
Rick
- Joined
- May 28, 2001
I see no mention of Scanmaster, or other data recording. You have such?
What's the fuel psi when this does it's thing? I see a new hanger, hotwire...New fuel pump, too?
IMO, a flat cam is a 100% of the time problem....Not just when it gets warm, and has been driven for some time.
What's the fuel psi when this does it's thing? I see a new hanger, hotwire...New fuel pump, too?
IMO, a flat cam is a 100% of the time problem....Not just when it gets warm, and has been driven for some time.
I did test it with the old cam sensor cap also. All this is not so bad if you have access to some spare parts to test out and troubleshoot. I did not have any parts available. After the car is warm, separate the coil from the ignition module and see if the potting material is soft and a mess of soft sticky goop. That could be one possibility.
2 things I will throw in the mix........where the after market downpipe goes over the frame it get very close to the return line for fuel and heats it causing vapor lock, also running a large pump like a 340 and using a stock return will cause a similar issue. I have personally experienced both of these issues while watching it happen on a fuel pressure gauge.
RunninShine231
Member
- Joined
- Feb 17, 2013
hmm... im curious of the lifters may losing prime essentially squeezing down causing mechanical miss, and ecm is attempting to correct resulting in the symptoms described. good to read these posts tho.
drove it yesterday for about 1 hr..started to act up a few times then i was at my destination..mid 80's...doesnt see to do it at speed just under a load i'm pretty easy on the car...so its not like i have been beatn the snot out of it then it acts up...i'm going to a friends later today hes an hr away and its mid 80's again..hopefully it will repeat then we can trouble shoot some..
- Joined
- Feb 18, 2006
The caspers led caps are notorious for exactly what you describe. I've fix several cars by replacing it with stock style.
