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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Pontiac Technician
Category: Pontiac
Satisfied Customers: 2378
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have a Pontiac G6 with the 3.5 V6 engine that does not

Customer Question

I have a Pontiac G6 with the 3.5 V6 engine that does not start all the time.On startup sometimes the engine will turn over but fail to start also sometimes the engine will continue to crank without the key turned to the start position and shake violently then stop almost like it’s out of time. I have tried repeatedly starting the car in my drive way waiting minute’s in- between starts. Started fine for about 10 or more starts then finally it started acting up. I do not know if was me trying to start the car to quickly but it shook and the belt tensioner bolt striped out of the engine. Put a longer bolt and fixed that but the starting problem still exist. No service engine lights on.Start the car move it 100 feet turn the ignition off wait 1 minute now restart engine it will turn over but not start .Once it is running it runs fine no hesitation no stalling run great. Have read all the post on line from position sensors bad, throttle body dirty, flare reprogramed and fuel pump starting to go out so can you diagnose the problem.
Submitted: 1 year ago.
Category: Pontiac
Expert:  Dan replied 1 year ago.

Hello, my name is***** it starting right now? If throttle body was problem it would start while holding down the gas.

Customer: replied 1 year ago.
It starts most of the time. I stopped driving it until I find out what is wrong. The violent shaking has already striped the belt tensioner bolt out once do not want that to happen again.
I never said It was the throttle body that's why I'm asking for a diagnoses.
Expert:  Dan replied 1 year ago.

I'd recommend starting with a fuel pressure test, fuel pressure should be at least 50 psi key on engine off. Let me know, thanks.

Customer: replied 1 year ago.
Turn key on gauge at 60 settles at 55 to 54. Turned key off it took 4 min's for pressure to 50psi held at 50psi for 4 min's before very slowly dropping from 50psi. Started car several times to warm engine to operating temp. Car started fine pressure at 60psl running. Started car several more times before it did not start pressure at 60psi when cranking. Also engine was cranking even after I stop turning the key. This is what it was doing so no surprise other than I know now it has fuel pressure now. Gauge was jumping but no more than two psi above and below 60 psi. I did not see this as a problem since it is not a liquid filled gauge. Starting the car It did this two or the times in a row but the pressure stayed at 60 psi. I did not try starting the car again because last time after two or three cranks but no start is when the engine starts to vibrate. So what do you think.
Customer: replied 1 year ago.
No reply anyone have suggestions.
Customer: replied 1 year ago.
Well it's been 5 days and no answer. Do not bother answering my question. Also do not charge my account.