Wont start without giving it gas

[sn95gt50]

2008 Grand Prix
Base Model
3.8L Series III

This does not happen all of the time, but, occasionally, when I try to start it, turn the key and it will try to start but won't. If give it just a little throttle it will start up every time.

A few things that I am guessing would be:

Fuel pump
Fuel Filter
Idle air bypass​

Is the pump filter a single unit?

Wondering if anyone else has had this experience and could help me rule somethings out before throwing money at it.

Thanks,
John

 

[sn95gt50]

FYI 130k miles, fuel pump filter IAB all original

 

[Scottydoggs]

it happen on cold starts only? if so then the iac could be bad.

 

[onxy]

Or if it's hot starts only I would investigate the Fuel pressure Regulator.

Does your coolant temp gauge work properly?

Pinpointing a common denominator in these cases is very helpful

 

[Scottydoggs]

Or if it's hot starts only I would investigate the Fuel pressure Regulator.

Does your coolant temp gauge work properly?

Pinpointing a common denominator in these cases is very helpful

pretty sure the fpr is in the gas tank on a 08, not on the rail like the older cars. and those dont seem to fail. at least ive never heard of one failing.

 

[onxy]

pretty sure the fpr is in the gas tank on a 08, not on the rail like the older cars. and those dont seem to fail. at least ive never heard of one failing.

that's highly likely. I can't seem to remember a FPR on a l26 rail.

In any case, it sounds like a fuel mixture issue. Either too much/too little fuel, or it's having a hard time metering air. Data logs would help, or ability to monitor live data, otherwise it's just guesses.

 

[sn95gt50]

I can only remember it happening on cold start, will check with daughter.

You mention data logging, the only thing that I have is a Bluetooth OBD2 reader, it has some data logging, what should I log, or is this not available?

Thanks for all input.

 

[Scottydoggs]

id find a cheap iac valve "idle air control" for cheap on ebay and toss it on the tb. local parts store will want retard money for it. ebay 20 bucks or so.