Nixhex

I have a 2005 Mustang V6.

It is currently in the auto shop for repair. They are telling me the car has 2 fuel pumps. A primary one on the left and a "transfer" pump on the right. They are saying that the "transfer" fuel pump doesn't work at all and needs replaced.

2 questions

1) Does my vehicle even have this so called "transfer" fuel pump?
2) If this "transfer" fuel pump was not working at all would the car start?

I am skeptical that the car has 2 fuel pumps as well as that the transfer pump is not working at all because the car will start and run. It stalls out after the car heats up but will start again once it has cooled for an hour or so.

Any help would be great. Don't want to pay to fix something that is not the problem. Thanks

JimC

The Mustang has a saddle type tank so there is a pump on the passenger side to bring the fuel across.

tx_zstang

Passenger side is not a separate electric pump, though. Actually, there's a float there and a hose for transfer to driver side. At least that's how it was in a '06 I had.
The pump is on the driver side.

Nuke

What's the issue that you have to replace the pump? There is a TSB for the 05's and 06's for the fuel pump where it generates air bubbles which cause hesitation/bucking on acceleration after extended (over 5-10 minutes?) of highway speed cruising. My wife had the fuel pump replaced in her '06 due to that.

06RubyFire

Did it fix the problem? I still am having issues with this. Sorry didn't mean to jack your thread.

Nuke

Absolutely.

JimC

That's right, I didn't explain it very well.

Torch_Vert

Yep, it's a single pump (even the GT500 which does have two places both on the driver's side). The pump assembly on the driver's side has a venturi siphon that pulls fuel from the other side through a second pickup line. (GT500 works exactly the same way even with two pumps. BOTH draw from the driver's side, with a siphon drawing fuel from the passenger side.

I would be VERY suspicious of that shop. Even if the car wasn't drawing fuel from the passenger side, it would have a different symptom: running out of fuel while the tank gauge still showed plenty in the tank.

If it truly is temp and fuel related, I'd at least consider Fuel Pump Driver Module (FPDM). It's the module that regulates the fuel pump, and it hides out in the spare tire well.

The F-150 guys have a LOT of trouble with these (on the trucks they get stuffed inside the from fender exposed to the elements). One of the symptoms they see is stalling with the ability to restart after sitting a while.

jimkaray

I think the mechanic is probably basically correct with his diagnoses but is making some assumptions about the Mustang's set up that's probably based on another Ford product he's seen in the past, or even other cars with the saddle tank design. Here's why I say this - Failing electric fuel pumps behave exactly in the way you are describing. They use fuel to keep them cool and when they get old they run hotter, add to that low fuel and/or hot fuel (thanks current heat wave) and there isn't enough cooling going on and it overheats. Next time it happens try adding 5 gal of fresh cool fuel and I'll bet it restarts without waiting an hour for it to cool down on its own.
As for the misinformation I doubt they've taken the time to look into the exact set up as I said. Based on the obvious pump issue they are just making an incorrect assumption on the actual set up. It isn't that important to them be 100% correct. When the tank is dropped they will see what's up and order the right pump, that is if the parts guy doesn't straighten them out with the correct info when the go to order a new pump. As long as they have a decent rep as an honest shop I wouldn't worry and just pass along the helpful info for them to look into.

Torch_Vert

Jim, they're being very specific with him that it's the supposed "transfer" pump not working. Not to say the main pump couldn't have a problem, but these guys are talking out their backsides, at least to some degree.