Fuel problem

[stang910]

I seen a few people have this same issue, but they never posted if they resolved the issue. My car is running 100% duty cycle at 4000rpm then the pressure begins to drop. Duty cycle at idle is 44% which I believe should be around 32%. I pulled the tank and verified both pumps are working and I'm getting no less then 13.2 volts under WOT. My plans are to put GT pumps and a fore hat in, but I would like to figure out the problem with the factory pumps before I upgrade.

Is it possible I just have some weak pumps? The car sat for a couple years due to a melted piston and I purchased it and installed a new engine. The car has a stock eaton and a ba2400 so I'm certain a stock fuel system shouldn't be maxing out and the MAF isn't either.

 

[Jimmysidecarr]

Your sig says you have a 2011 GT and that's it.:dw::shrug:

 

[trickflow coupe]

he has an 03 cobra as well

 

[stang910]

Yeah I own a 2003 sonic blue cobra also. I've owned the 2011 longer then I've had the cobra. I just haven't updated my sig is all.

 

[cobracide]

Yeah I own a 2003 sonic blue cobra also. I've owned the 2011 longer then I've had the cobra. I just haven't updated my sig is all.

Update your sig with all your mods and we can try and help.

 

[stang910]

Update your sig with all your mods and we can try and help.

updated

 

[wilderyzed]

Sounds to me you are just out of pump or its time for a BAP thats what happened when I pegged my pumps thats typically how it will datalog too when that happens

 

[stang910]

The car put down 441rwhp and started running out of pump way before redline. AFR stayed below 12.0 for the full run, but pressure went down to about 13 psi at the rail. Car would of put down more power, but timing was kept to a max of 16 degrees cause of the lack of fuel. I know the cobra pumps will support more then 441rwhp without pressure drop.

 

[Jimmysidecarr]

updated

Excellent thanks!:beer:

Sounds to me you are just out of pump or its time for a BAP thats what happened when I pegged my pumps thats typically how it will datalog too when that happens

Ditto, I think it's time to address fuel delivery.

Either go with your plan now, or keep the stock pumps and do a BAP and wire upgrade.

Stock pumps will support beyond 600 RWHP on a twin screw car, if you have a BAP and wire upgrade. Lots of cars are beyond that level with that fuel set up.

 

[mach1033]

This may sound silly but did you by any chance change the fuel filter being that it sat for 2 years and I'm sure it gunked up?

 

[stang910]

This may sound silly but did you by any chance change the fuel filter being that it sat for 2 years and I'm sure it gunked up?

It's got a brand new filter in it.

 

[mach1033]

It's got a brand new filter in it.

Stock fuel rails as well?

 

[stang910]

Yeah stock fuel rails. Then entire fuel system is stock except for 60lb injectors. I'm starting to think I just have some weak pumps.

 

[mach1033]

Yeah stock fuel rails. Then entire fuel system is stock except for 60lb injectors. I'm starting to think I just have some weak pumps.

The only reason I ask is because when I blew up my motor on my fox GT the car sat for a little over a year and I had to change the fuel lines and filter cause the fuel varnished. This was back in the early 90's and I did a rookie mistake of not addressing that issue. Hopefully its just the pumps being weak. What upgrades are you gonna do?

 

[stang910]

I'm gonna run GT pumps and dual FPDM's. Then I'm gonna put a Whipple 2.9 on the car. Hoping to have this done before the end of the year.

 

[mach1033]

I'm gonna run GT pumps and dual FPDM's. Then I'm gonna put a Whipple 2.9 on the car. Hoping to have this done before the end of the year.

In that case get the triple hat with the 2 pumps. That way when you do go to the 2.9 you can just add the third pump, module and injectors. Your gonna need it if you plan on boosting it. I'm at 23lbs and with 60's, fore hat and twin pumps it maxed out.

 

[stang910]

In that case get the triple hat with the 2 pumps. That way when you do go to the 2.9 you can just add the third pump, module and injectors. Your gonna need it if you plan on boosting it. I'm at 23lbs and with 60's, fore hat and twin pumps it maxed out.

I was thinking about getting a triple hat or getting a 40 amp BAP. Not sure which direction I'd like to go.

 

[cobracide]

I was thinking about getting a triple hat or getting a 40 amp BAP. Not sure which direction I'd like to go.

Talk to your tuner about it, he should be able to do triple pumps if he's good. If he's not experienced with triple pumps, either go to a new tuner that can do it or go with the BAP.

BTW - I see you are in NC - where about? In Charlotte, Dan at Pro-Dyno is very good.

 

[stang910]

I'm in jacksonville. It's on the coast about 4-5 hrs from Charlotte.

 

[cobracide]

Also consider a returnless fuel system - http://www.svtperformance.com/forums/engine-tuning-214/752339-anybody-run-3-fpdms-3-fuel-pumps.html