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I have a 2008 GMC Sierra 1500 Z71 4X4 with a starting issue. Can anyone help?
sgtmggjr55
Member Posts: 3
About two years ago I was out hunting and on the last night I was there the temp dropped down to about 6 degrees. The next morning my truck would not start. When I turned the key it just cranked over. it took about four or five attempts but it finally started. Ever since then I have had the same problem every time I go to start it. It always starts, but it takes two and sometimes three key turns to start. Sometimes it only takes one time but about 95% of the time it takes two turns to start. The local dealer said that it was the fuel pump the first time I took it there and then two months later they said it was the Throttle Position Sensor. Then a few months ago a local oil change place ran a test on it when I was having the oil changed and they said it was most likely the Mapping Sensor gone bad, not allowing enough air or something like that. Does anyone have any clues as to what it might actually be? Please help if you can. Thanks.
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Answers
Second would be that a temperature sensor for the coolant has failed and is giving the wrong temperature to the computer. This means the injectors are not putting enough gasoline in for a cold start.
Third is that it might be the MAF--mass air flow sensor. I am not an expert but with some of those disconnecting the snap on connector before cranking and then seeing if it makes a difference in how the car starts _might_ indicate something.
If it were the throttle position sensor, you might notice some odd reactions other times from the computer getting the wrong indication about the position of the accelerator pedal. You didn't mention anything like that.
2014 Malibu 2LT, 2015 Cruze 2LT,
Usually the loss of prime is overnight like you say, and the car starts well for a few hours after having been driven. There might be something more here in the loss of pressure.
As I've been thinking about this person's problem while doing other things, I realize it also could be the fuel pressure regulator on the line at the engine. It could be leaking the pressure from the fuel line into the vacuum line that leads directly to the engine. I recently read someone with a 3800 engine that had strange starting problems and that was what he replaced that fixed it.
But I'd expect that to give a start first and then stall, which I believe was his symptom for the other car I mentioned.
2014 Malibu 2LT, 2015 Cruze 2LT,
I know this is an odd problem but any info I can get would be appreciated. Temperatures where I live are very moderate to extreme heat, 50's to 70's in winter and summer is always around 115, so I do not believe cold weather is the issue.
But you mention that you're in a warm climate... Find someone with an upscale reader for the codes. The more upscale ones can read data from the computer. You may even be able to get a loaner scanner from one of the box stores. I have one that tells me the temperature of the coolant that the sensor is reading. When the truck is cold, see if that coolant temp is nearly ambient temperature with it being closer the longer the truck has sat. If the computer thinks the truck engine is warmer than it really is, then the amount of fuel it injects won't be enough for that quick start.
Try starting with MAF unplugged at its clip.
You don't mention anything to indicate there might be a problem in the spark part of the engine.
2014 Malibu 2LT, 2015 Cruze 2LT,
I think this may fit your situation with the check valve in the fuel pump might be your problem. But diagnosis is key to being fairly sure before replacing a part.
http://www.silveradosierra.com/vortec-5-3l-v8/fuel-pump-or-pressure-regulator-t4441.html
2014 Malibu 2LT, 2015 Cruze 2LT,
Any other ideas fellas? I leave in the next week to go hunting again and have a long drive to get there. I don;t want issues on the road if I can help it.
I see you're requesting assistance from the members of the forum to resolve this concern yourself. If you decide to bring it in to the dealership before your trip, feel free to reach out to us via private message. This message should include your VIN, contact information and current mileage. I look forward to your update with regard to your progress with this concern.
Marlea W.
GM Customer Care
2014 Malibu 2LT, 2015 Cruze 2LT,