05 Ford GT power loss

[charlie27]

hi, yesterday driving a new to me GT with 3.5l whipple and large accufab TBs. I was doing a spirited run in 4th gear and all gauges were nominal and boost was 15+ psi. Full throttle. Then I lost power. Car still ran but now only seeing 2-3psi boost and wont rev out. I suspect supercharger bypass valve since no boost. I pulled the valve and not sure how to test it. I know unpowered it is open - not sure if that is correct.

Any help appreciated. thx Charlie

 

[TO AWSUM]

The FGT will go into limp mode if it is having a problem. It will limit the speed to 45 mph. Everything else will look normal and you can accelerate to 45 mph slowly or rapidly. There could be many things to cause it to go into limp mode. Mine had a weak battery. The car would start easily, ran well going out to a restaurant, but on the way back it suddenly went into limp mode about half way back. Turned out the amps were low, but the battery was not dead and the car started normally. Replaced battery and everything was fine again. Could also be a bad electrical ground which is common. Remove ground from frame, clean, reinstall. Maybe that will fix your problem.

 

[fjpikul]

Heat soak?

 

[CanadaGT]

Valve is easy to check, suck on inlet and if it holds, it is good.

 

[Art138]

hi, yesterday driving a new to me GT with 3.5l whipple and large accufab TBs. I was doing a spirited run in 4th gear and all gauges were nominal and boost was 15+ psi. Full throttle. Then I lost power. Car still ran but now only seeing 2-3psi boost and wont rev out. I suspect supercharger bypass valve since no boost. I pulled the valve and not sure how to test it. I know unpowered it is open - not sure if that is correct.

Any help appreciated. thx Charlie

Can you take a pic of the supercharger valve?

 

[charlie27]

with the valve off the car, the valve is wide open - meaning bypass

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this valve

 

[soroush]

if for some reason the secondary injectors are not coming on you will experience what you are describing.... its one place i would look into.. there are drivers for the secondary pump and relay in front of the car

 

[nota4re]

Working with the op now. The cause of this is the secondary fuel pump. We'll replace and have back on the road shortly.

 

[2112]

Working with the op now. The cause of this is the secondary fuel pump. We'll replace and have back on the road shortly.

Does that require tank removal or is it accessible from inside the cockpit?

 

[mmlcobra]

For people with experiance, does not require tank removal.
Heffner did mine.
Need to know what you are doing!
Best,
Mark

 

[Tomcat]

Working with the op now. The cause of this is the secondary fuel pump. We'll replace and have back on the road shortly.

Great find!

 

[Tomcat]

Working with the op now. The cause of this is the secondary fuel pump. We'll replace and have back on the road shortly.

Great find!

 

[twobjshelbys]

It's good to get a post with a resolution. So often here and other places we never hear what it took to fix a problem! Thanks for following up!

 

[MNJason]

Kendall to the rescue again!

 

[analogdesigner]

What was the outcome of this problem?

 

[68Rcodeman]

What was the outcome of this problem?

Secondary fuel pump not supplying fuel demand.

 

[nota4re]

Due to coordination of work and play schedules, the car just arrived last night! The car is presenting that the primary fuel pump motor is history, but it could very well be the secondary if the wiring at the pumps has been reversed (both fuel pumps are identical). The surgery will start during the week as Ryan flew up to Oregon today to work on another GT and is back Sunday night. I'll post update when resolved... but we've done a lot of these.

 

[eric dauber]

My local Ford dealer has diagnosed that one of my fuel pumps is bad. Unfortunately they are unable to locate a replacement. Can anyone suggest where I can find one?

 

[Tipo874]

I had a fuel pump go out and replaced it from my spares. The ford GT pump is unavailable for several months without an availability date. There is a walbro replacement pump with the same voltage tables but a delphi connector which would cause modification.

 

[NorthwoodGT]

just went thru something similar on another GT. secondary fuel pump was not coming on. showed up in the diagnostics. turned out one of the fuel pump drivers was off line. switched drivers and worked great but also re-installed the old driver to find out that it was the ground that went bad, not the driver or the fuel pump. simple fix. thank GOD!