ohnoesaz

Car: 2005 Mustang GT, regular boltons

Mileage: 24500

Sequence of events:

1. Installed upper control arm, DID NOT drop fuel tank.
2. Two days later get gas for first time since UCA, and upon startup the gauge goes down to zero. It slowly goes up again.
3. Happens during every drive for next3 days. Guage reading appears accurate when its working.
4. Last night use Shell fuel system cleaner with 3/4 tank fillup.
5. Today on drive to work, during rainy cold morning, guage goes back down to zero. Now a CEL comes on.
6. Drives fine to work, plug in predator to read trouble code but it says "No trouble codes found". Test startup, check-engine light still there.
7. Leave for lunch break, something from the rearend screams when ignition key is turned (before full startup). Its the fuel pump right? It moans for a few seconds and then the car starts up fine.
8. Coming back from lunch. Car got cold quickly due to cold outside, on startup the same thing screams loudly again, and this time the car sputters when trying to start for about 2 seconds. It kicks in and starts.
9. Back at work, car is heated up, I'm able to start and shut it off consistently, no screaming.


Car drives fine, at least it feels like it...

Anyways, at first it sounded like the TSB for erratic fuel gauge, but then it sounds like a dead fuel pump.

HELP!!!!! [8D][8D][8D][8D]

billyjo

if you can lift car check the wire connection for the fuel pump to see if you moved it or hit it. But the sound is your fuel pump. Could be plugged filter and the pump fighting the resistance in the line until the fuel heats up due to the return of unused fuel. Recommend to change fuel filter and see if continues. if does go to dealership due to warrenty should be covered.

ohnoesaz

I bought it with 6K miles (wow i drove a lot in a year!) and anyways I remember the salesman saying the warranty is done in february. Now. But either way I wouldn't want to fight about my mods.

I changed the filter a few thousand miles ago, it was pretty clean also.

I dont mind spending $$$ to fix a problem on my own, I just want to be sure Im diagnosing it right, and hear people's theories.

hammeron

hope you get it fixed

ohnoesaz

Hey guys... I pass by a dealer on the way home from work everyday, so today I stopped in and spent $250 on a new fuel pump module (you know, the whole bracket thing with pump and sender etc). I hope this fixes the problem, but either way I figure I plan to have this car for a long time so investing in replacing a part like this can't hurt.

Ill update this thread on whether everything is fixed or not

ohnoesaz

Well guess what.... i went to install the new fuel pump and noticed I smelled gas in the garage. So before installing the pump I looked around... Ah, some gas on the fuel filter cover!

I pop the cover and theres a small puddle in there. But gas evaporates so quickly that it might have been a lot of gas at one point.

The connection going to the fuel filter, which I installed, was very loose and unclipped. I clipped it back in.

On startup, sure enough the fuelpump screamed as it worked to put pressure back into the system. Immediate car shutoff and sat for 10 minutes. On startup, nice 'click' on from the fuel pump, which is what I've always heard before this drama.

So maybe a leaky filter connection caused bad pressure?

Ok fine, so what explains the fuel gauge constantly going to zero and creeping up again.... Thats based on a fuel float, not pressure... But who knows?

PhattyDre16

Are you getting a "DTI Fuel data error" in your message center?

ohnoesaz

I dont have a message center... just the lame basic dash.

But anyways, after I fixed the fuel filter leak, the fuel pump no longer whines on startup as it tries to put pressure back into the system. In fact, its quieter than its ever been. The fuel gauge plummeted once after the fix but thats it, and its been about a week now.

So yeah... anyone who has these problems should consider a system pressure leak just as much as component failure...