Starting Issues... Fuel Pump, Theft Deterrent, Or Something Else?

[Chad Gervais]

Greetings

I have a 2004 GT2 with 214000 miles. For the past couple months, she has been funny about starting. If the car sits for more than 30 minutes, it will just keep cranking but not start. If I turn the key to RUN then OFF then RUN again it fires right up. My first thought was dirty injectors so I got a bottle of injector cleaner which did nothing. My next thought was the fuel pump.

I work in an auto parts store and I was asking a coworker about it, he told me that with GM's the anti theft system can go funky and cause that. He asked if i could hear the fuel pump when I turn it to RUN, which I can. He says its not the pump because with those, they either work or they dont.

Any thoughts on what this could be? Other than that she runs like a top. It did stall on me once back in May but that was the day i ran the injector cleaner, im thinking it loosened up some crap that choked the engine or something.

[Fivefingerdeathpunch]

Ever clean the throttle body and MAF yet?

[Chad Gervais]

FFDP,

no, but my mileage is not suffering and the engine runs smooth once it starts, I doubt the throttle body is causing this

[Scottydoggs]

did the tach drop to zero back in may when it stalled, before it stalled? if you noticed. or does it ever just stop working? i know it was a ways back.

kinda sounds like crank sensor going bad.

[Chad Gervais]

the morning it stalled, it was weird, i was going uphill and the more i pressed the gas the lower the tach went, when i let off, it went back up a bit, until it just died. Thats what led me to suspect the injector cleaner, the more gas i gave it, the more IC it sucked into the system

[Chad Gervais]

to add, i have a code scanner. At no time has the car thrown a code. My coworker says that a failing fuel pump will cause the engine light to come on

[Scottydoggs]

crank sensors are known for not throwing a code.

at 214,000 miles your cat could also be clogged up. see if its glowing red at night after diving it. or bang on it when its cold, to see if you hear anything rattling around in side it.

injector cleaner should not make the car feel funny, if any thing it should feel like it has a tad bit more pep.

and im not 100% sure on the bad fuel pump setting a code. but would think it wont.

the best thing to do is check the fuel pressure at the rail with a pressure tester.

[Chad Gervais]

hmmm,

it seems many of these things would manifest while driving, not just when trying to start the car. I have more than enough power, a clogged cat would cause power loss. Bad crank sensors are known for causing backfiring, RPM fluctuations, and inability to start at all.

checking fuel rail pressure... is that something a layman like myself can do with a rented tool? Or do i need to pay the ridicuous hourly rate at the shop for that?

[Scottydoggs]

you can rent a tester, and do it, its easy, just un cap the valve on the fuel rail, and screw the tester on it.

[Fivefingerdeathpunch]

I'd still just for the fact of how many miles are on the car, clean the TB and MAF sensor.

[Scottydoggs]

I'd still just for the fact of how many miles are on the car, clean the TB and MAF sensor.

hes right. it cant hurt.

i bet the back side is black and thick. mine was pretty nasty at 213,00 when i cleaned mine. who knows if it had ever been done before.