03 GTP dies in cold weather

[rlo]

This is a strange one. 30000 mile car. Last winter when temps would drop into the 20s, car would die while driving as if you had shut the key off. No check eng light, no loss of elec pwr, just died. You could hear the fuel pump fine, but car wouldn't start back up for about 5-10 mins. The colder it was outside, the longer it would be before it would start back. After this happened about four or five times, I parked it. Changed fuel filter, put heet in tank, checked fuel pressure and spark. Decided to change fuel pump, new from gm, and car started and ran fine. Consequently, This was when the weather was warming up in early spring. Thought all was well until November when temps dropped into the 20s again. Same thing all over again. After about three mornings in a row, the third time it would not start at all. I left it on the side of the road and caught a ride to town. Was prepared to tow it to town at lunch and it started right up, so I drove it directly to the gm service shop and left it. They were already aware of my dilemma and are really trying to figure this one out. They have: checked fuel pressure, crank pos sensor,spark, scanned for codes(none found), checked for bad connections, checked BCM, even ordered a new PCM and tried it on my car, all of these to no avail. Keep in mind that these guys are very competent and are really going out of their way to help me, but we are about out of ideas. Sorry for the lengthy post, but I would like to know if anyone else has ever had this prob. Thanks

[BNaylor]

Sounds like your GTP is under warranty so it will be their responsibility to resolve the issue no matter what they have done to date. But here are some suggestions which are back to the basics, ignition and fuel. Did the dealer monitor fuel pressure duplicating your conditions when the temperature gets into the 20s. Although the fuel pump was changed, there is a fuel pressure regulator and fuel pump resistor that could give you a similar problem. Did they provide you with the readings with and without vacuum connected to the fuel pressure regulator?

Also, I would not rule out the crank position sensor (CKPS) for ignition. It could be sensitive to temperature conditions. Normally they don't like heat. In your case it is the opposite. Many times no DTC error codes or SES light on a CKPS. Again your conditions have to be duplicated and that may not occur when it is in a shop hooked up to a Tech II diagnostics machine.

[rlo]

Originally Posted by bnaylor3400

Sounds like your GTP is under warranty so it will be their responsibility to resolve the issue no matter what they have done to date. But here are some suggestions which are back to the basics, ignition and fuel. Did the dealer monitor fuel pressure duplicating your conditions when the temperature gets into the 20s. Although the fuel pump was changed, there is a fuel pressure regulator and fuel pump resistor that could give you a similar problem. Did they provide you with the readings with and without vacuum connected to the fuel pressure regulator?

Also, I would not rule out the crank position sensor (CKPS) for ignition. It could be sensitive to temperature conditions. Normally they don't like heat. In your case it is the opposite. Many times no DTC error codes or SES light on a CKPS. Again your conditions have to be duplicated and that may not occur when it is in a shop hooked up to a Tech II diagnostics machine.

The day after I dropped it off, temps were in the teens, they tried to drive the car and made it about 1 mile when it quit. They towed it back in to the shop and the next morning(temps still cold) they had a fuel pressure gauge taped to the windshield so they could monitor that while the tech drove it again. Car died again and the tech said the fuel pressure was fine although I don't know the exact reading. He also had a handheld scanner with him that indicated nothing. He stated that it had fire as well. After towing it back to the shop, they ordered the pcm, which didn't make any difference. The car is not under warranty, so they are trying to work it in and out of the shop as time permits. If the crank sensor was bad, would it still have spark? Thanks for the reply.

[BNaylor]

Originally Posted by rlo

The day after I dropped it off, temps were in the teens, they tried to drive the car and made it about 1 mile when it quit. They towed it back in to the shop and the next morning(temps still cold) they had a fuel pressure gauge taped to the windshield so they could monitor that while the tech drove it again. Car died again and the tech said the fuel pressure was fine although I don't know the exact reading. He also had a handheld scanner with him that indicated nothing. He stated that it had fire as well. After towing it back to the shop, they ordered the pcm, which didn't make any difference. The car is not under warranty, so they are trying to work it in and out of the shop as time permits. If the crank sensor was bad, would it still have spark? Thanks for the reply.

If you can get the reading from the Tech it may help. One symptom of a defective fuel pump resistor is the fuel pump cannot switch into high speed and bump the fuel pressure up. The fuel pump speed control relay located in the engine compartment fuse box does not energize. Symptom is car will run for a few seconds to few minutes and then stall out. The GTP has a two speed fuel pump.

On the CKPS they need to monitor the 18X pulse output of the sensor. The CKPS establishes the ignition timing not just spark. Actual spark is generated by the Ignition Control Module (ICN) and ignition coil packs in which the CKPS feeds. 18X pulses also feed the tachometer. Other possible symptoms to watch for is the tach will abruptly drop to zero a split second before you realize it has stalled. It may be accompanied by an ABS light and trac off light due to the stallout condition and the car is still in motion. The problem with most CKPS problems is when checked spark will appear to be correct but it may not be at the time the fault occurs. Very intermittent. Electrical/electronic components are subject to weather conditions, both heat and cold.