Bad Fuel pump?

[12Red500]

Hi guys.
Could use a little advice for the experts around here.

Saturday I had an issue with my car (2012 gt500) where it is not getting any fuel and would not start.
Prior to that event, I noticed fluctuating fuel pressure topping out at 50 psi but bouncing around erratically to a low of 12psi.
The car sputters under any acceleration, ran lean 17.x AFR where it typically run 13.9/14 AFR off and on.
Error codes mention low fuel pressure.

I was in the process of getting her home when I made a stop and she would not start.

I had it towed to a garage and because it is modified they can't figure out how to fix it.

2012 5.4 wirh Gen 2R 67mm TB
CAI 54lb injectors
VMP fuel pump booster
Had in this configuration for 2+ years without issue.

Going to have her towed home tomorrow and fix it myself but I could use a bit of help with diagnosis.

Do you think the fuel pump went bad or should I check the FPDM?

 

[HKusp]

Start by checking the VMP fuel pump booster. I had a Kenne Bell BAP go bad on me years ago and it did something very similar.

 

[Vinnie_B]

What are the fault Codes? I believe you are local to me. If you need help troubleshooting your fuel system let me know.


Lightning FastElectrical Automotive Repair
PM Me or [email protected]
Website:Lightning Fast Electrical Automotive Repair LLC
Remote or Local (On Site) Technical Repair

 

[12Red500]

What are the fault Codes? I believe you are local to me. If you need help troubleshooting your fuel system let me know.


Lightning FastElectrical Automotive Repair
PM Me or [email protected]
Website:Lightning Fast Electrical Automotive Repair LLC
Remote or Local (On Site) Technical Repair

Thanks for the offer Vinnie_B.
We'll have to meet up sometime.

 

[12Red500]

Start by checking the VMP fuel pump booster. I had a Kenne Bell BAP go bad on me years ago and it did something very similar.

What are the fault Codes? I believe you are local to me. If you need help troubleshooting your fuel system let me know.


Lightning FastElectrical Automotive Repair
PM Me or [email protected]
Website:Lightning Fast Electrical Automotive Repair LLC
Remote or Local (On Site) Technical Repair

HKusp....I owe you a beer at the very least.
As a test I disconnected the booster and she started right up.
Got to do a few more tests to confirm but looks like you are correct.

Now just need to find a new booster.

Thanks brother!

 

[LS WUT]

Start by checking the VMP fuel pump booster. I had a Kenne Bell BAP go bad on me years ago and it did something very similar.

This. Had a few go out on me in my cobra. They’re finicky.

Edit: I’m dumb. I didn’t read the last post until now. Lol sorry. Wish you luck brother.

 

[biminiLX]

Couple other thoughts.
Is this the original fuel pump?
When has fuel filter been replaced/cleaned? When have fuel injectors been cleaned?
Last, what fuel?
-J

 

[Vinnie_B]

Thanks for the offer Vinnie_B.
We'll have to meet up sometime.

Sounds good @12Red500 If any other issues come up or you would like a complete health check from bumper to bumper on the GT500 or any Ford vehicle let me know.

 

[12Red500]

Couple other thoughts.
Is this the original fuel pump?
When has fuel filter been replaced/cleaned? When have fuel injectors been cleaned?
Last, what fuel?
-J

This is the original fuel pump (30,000 miles on it)
Fuel filter was not replaced.
Injectors are new and have about 3000 miles on them (if that much).
I run 93 oct fuel.

The pump wasn't even coming on with the booster connected.
When I removed it, suddenly the pump started working.

 

[HKusp]

HKusp....I owe you a beer at the very least.
As a test I disconnected the booster and she started right up.
Got to do a few more tests to confirm but looks like you are correct.

Now just need to find a new booster.

Thanks brother!

You're are very welcome. Glad you figured it out. Get your hands on a JMS unit if you can. They are programmable for progressive amounts of boost. It's not always on. They last longer and don't heat up the fuel.

 

[biminiLX]

This is the original fuel pump (30,000 miles on it)
Fuel filter was not replaced.
Injectors are new and have about 3000 miles on them (if that much).
I run 93 oct fuel.

The pump wasn't even coming on with the booster connected.
When I removed it, suddenly the pump started working.

Glad you got it figured out.
I believe the ‘12 still has a single pump?
Even tho only 30k mikes it still is 10yrs old.
New pumps flow a bunch more. The ‘Hellcat’ Walbro 292 (maybe 284?) probably could support your power on 93 even without a BAP.
I thought JMS may make the VMP booster but either way they may be able to repair it.
-J

 

[HKusp]

I am pretty sure the VMP is made by tge same people that make Lethal Performance's units.