[gcone]

Hello all. Just picked up a new GTO and have a problem. The car mysteriously stalls upon start-up (sometimes). Its a six speed and no I'm not popping the clutch too early. I've gone through the dealer supplied gas and filled it with 93 octane. The problem has manifested itself during cold and warm start ups.
The car starts every time but stalls in about 1-2 seconds. Then later on in the day it starts and runs fine. I've got the car in for warrenty repair but of course, the problem did not occur (so far) there.
I even (heaven forbid) refered to the owners manual to see if I'm starting the car correctly (I am).
Any thoughts would be appreciated.

 

[Old Coot]

Could be a problem your theft protection.

 

[Davjefdunn]

The key has a chip in it. Try using the other key supplied with the car. If it dosent cut out then the problem is the key chip

 

[gcone]

Ok, the problem has happened on 5 different occasions now and is in to the dealer for the second time. They cant get it to stall and they think that the problem is driver error. They have used the same key as when it was having the problem so I am not sure that is it.

The dealer has not focused on the problem whatsoever as they are trying to duplicate it. They have not found any error codes but I dont think they are even trying to solve it.

I will ask if they have checked out the security system and if you guys can think of anything else let me know. Will keep this thread informed with any update.
Thanks for the suggestions.

 

[gcone]

Regarding the key. I will carry the second key with me and if the car cuts out upon start up, I will substitute the other key. Worth a try but right now the car is at the dealer.

BTW, the car never has a stalling problem once it it running for more than a couple of seconds. It only mysteriously stalls immediately after start up.

 

[Davjefdunn]

Thats why i think it may be a key. When you start you car the chip is recognized. If it is not the car will atomatically shut off after a couple of seconds. If the key is recognized properly then it wont cut off. I am pretty sure there is some kind of problem with the theft system on the car. Good luck!

 

[westell]

I'd get them to test a gas sample, which they may do anyway.

 

[Davjefdunn]

If gas was the problem it would do it all time, or while driving the car was running the bad gas would cause a misfire code to appear.

 

[westell]

If gas was the problem it would do it all time, or while driving the car was running the bad gas would cause a misfire code to appear.

unless, while the vehicle was still the pollutant or additive settled to the bottom but after movment mixed with the gasoline

it happened to me once; you're probably right.

put an update here when you figure it out, it's interesting, frustrating, i know when dealer "cannot duplicate" good luck.

 

[GTO TOO]

Have them check the Min. air setting on the throttle body. One way to do that is check the IAC position with the engine fully warm and after the engine has settled down to it's normal command RPM. They can use a Tech II tool and read the IAC position. If the Min. air setting is too low, too much of of idle control is dependant on the IAC motor. When the engine is cold that can cause problems. Or it could be a vacuum leak, either way checking the IAC counts can detect what the issue might be.
The fix is to turn the idle screw out ( just a little bit, as you want some IAC counts at idle ) They ( the dealer ) should know what normal IAC counts should be.

 

[bsmcall]

From having asked too many technicians too many questions, it seems as if the common starting problem with any of my 5.3liter engines (in the fleet) is the fuel pressure regulator. The diaphragm develops a leak which allows fuel to bleed into the intake at start-up. If the vacuum line is removed and the key energized, there should be no fuel at the vacuum port. The fuel pressure regulator is on the driver's side fuel rail( It's the only part on the fuel rail with a vacuum line.) BTW, it is the same part (at least externally) on the GTO 5.7 as it is on the 5.3 in a pickup truck.

i.e. Disconnect the vacuum line and inspect for fuel.
p.s. if my CHEVY dealer stocks it, it must be a common failure