Low Fuel Pressure Issue in 01 Cobra

[2000GTSTANG]

Ive got an 01 Cobra with supposedly an 03-04 Cobra fuel hat and/or tank with twin SVT Focus pumps. The car was turbocharged at one time, now it is stock. Stock tune on the PCM, stock 24lb injectors, stock 80mm MAF.

I cannot rev this thing over 4k rpm while driving. It will rev all the way to 6k, with no issues, while in neutral. Seems to run pretty good under 4k. Sometimes I have a hard time getting it to start up again after its warm, but it will eventually start again.

Im seeing low 20s PSI on my X4 logging the pressure drop PID. It will dip into the teens or slightly lower when revving. I was able to get 39psi ONE time with key on engine off. Taking the vacuum hose off the FRPS, makes the pressure drop to around 11. I haven't removed the electrical connector with the engine running, but with key on engine off, I see 70 on my X4.

I cant remember the fpdc PID but it is very low, almost 0, and doesn't seem to fluctuate at all.

I do not have fuel coming out of the FRPS. The sensor is off another 2v 4.6 Explorer 03+. I see no reason why the sensor would be bad but it could be reporting weird things. I will try to snag another sensor from the junkyard and see what it does.

I have not yet put a mechanical pressure gauge on the rail but I plan on doing that this week.

I plan on dropping the fuel tank as well to see what is inside of it. Possibly the socks on the fuel pumps are clogged or a line has popped off one of the pumps. Sucks that I have a little under 3/4 tank of fresh gas so I may drive the car and try to burn as much as I can.

The car did sit for a long time with almost no fuel in it.

Fuel filter was replaced last month with a new Motorcraft filter when I had the IRS out of the car.

Could having dual SVT Focus pumps in a stock setup cause this problem?

Anyone else ever run into something like this?

 

[wkornf]

I swapped to a single svt focus pump in the stock bucket with stock wiring and it works great. no issues with fuel pressure.

you could have a bad pump/ wiring or clog. maybe pull the field line off at The rail and hot-wire The pump into a bucket. it will lighten the tank And Tell you alot about flow rate

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[2000GTSTANG]

I swapped to a single svt focus pump in the stock bucket with stock wiring and it works great. no issues with fuel pressure.

you could have a bad pump/ wiring or clog. maybe pull the field line off at The rail and hot-wire The pump into a bucket. it will lighten the tank And Tell you alot about flow rate

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Years ago, I swapped over to a single SVTF pump in my 2002 GT and had no problems with the stock tune. Now I wish I wouldn't have traded that pump when I replaced it for a larger one lol.

Back to the 01 Cobra..

Purchased a fuel pressure gauge from Harbor Freight and confirmed that im only getting 10 psi of pressure when the car is running and about 8 psi KOEO. That 8 psi holds steady so there is no leak anywhere in the system. Fuel pressure drops when I unplug the vacuum line to the FRPS or disconnect the electrical connector, with the engine running.

I connected another FPDM from a v6 car and still get the same fuel pressures so definitely the FPDM is not the probem. I was worried that it might have been weak from having a BAP wired post FPDM with no wiring upgrade.

My plan is to drop the tank when I return back from Houston and see what is going on inside of it. I have a spare tank wiring harness pigtail, so I can hot wire the pumps easily to drain the tank and/or see what happens when 12v is applied to them.

I might purchase a pair of OEM GT500 pumps just in case these SVTF pumps are bad. I dont see how 2 of them can fail like that

 

[01yellercobra]

Even if only one is bad it'll cause issues. I ran AEM 320's for a bit and they worked fine. Then I started having issues at WOT. I could drive it all day at part throttle. As soon as I punched it I could watch the fuel pressure drop to 0. I later found those pumps weren't compatible with the returnless set ups. So there's a chance only one is bad. But how do you check it? I ended up swapping my GT pumps back in and it's been fine since.

Are you sure the GT500 pumps will work? I haven't heard of anyone using them. It would suck to order them and then find out they don't fit or whatever.

 

[BigFatMatt]

I swapped to a single svt focus pump in the stock bucket with stock wiring and it works great. no issues with fuel pressure.

you could have a bad pump/ wiring or clog. maybe pull the field line off at The rail and hot-wire The pump into a bucket. it will lighten the tank And Tell you alot about flow rate

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These are good suggestions, when my pump went out in my '99 I almost went this route. Like you OP, I'm on the stock tune, stock injectors, stock MAF, etc. so I wanted something I knew would work with my stock components.

Look into deleting the PPRV valve if you only swap the pump, it's been known to cause hesitation when shifting at high RPM.

I ended up going with a BBK 320 lph fuel hat & pump because I didn't want to mess with the lines or soldering. The hat is basically identical to stock, but it doesn't have the PPRV valve. The fuel lines looked a little thicker and felt more flexible than OEM but other than that it looked identical to my stock pump & hat.

Here is mine I believe:
BBK Mustang Direct Replacement Fuel Pump 1862 (99-00 All)
When I bought it a couple years ago, it was rated at 320 lph and it was also like $300 I believe. They specify another model for your 01 Cobra so make sure you get the right one.

It's been flawless for me, I noticed an improvement in throttle response and my car ran smoother. It dropped right in and I haven't had a single issue in over 2 years of somewhat aggressive weekend driving, also including 3 hour drives to the beach and back.

I've read BBK has issues with their header quality, and their expensive throttle body is basically useless... but my experience with this fuel pump & hat is very positive. It installed just like stock, and was plug & play. Just as quiet or quieter than my stock pump also. No issues whatsoever and I'm happy with it.

 

[2000GTSTANG]

Even if only one is bad it'll cause issues. I ran AEM 320's for a bit and they worked fine. Then I started having issues at WOT. I could drive it all day at part throttle. As soon as I punched it I could watch the fuel pressure drop to 0. I later found those pumps weren't compatible with the returnless set ups. So there's a chance only one is bad. But how do you check it? I ended up swapping my GT pumps back in and it's been fine since.

Are you sure the GT500 pumps will work? I haven't heard of anyone using them. It would suck to order them and then find out they don't fit or whatever.

I bought the pumps off eBay from Brenspeed. They were take outs from a 07-09 GT500. The part numbers on the pumps match the SVT Focus pump and they have green tops as well. They look identical to the SVTF pump I used to own. Only reason for going with them is the car supposedly has SVTF pumps already with an 03/04 hat so its just easier to stick with them. Plus the car will have a fuel system that's ready for boost later on.

Ive yet to take the tank down, hoping to get to it this weekend. Ill post my findings when the time comes.

These are good suggestions, when my pump went out in my '99 I almost went this route. Like you OP, I'm on the stock tune, stock injectors, stock MAF, etc. so I wanted something I knew would work with my stock components.

Look into deleting the PPRV valve if you only swap the pump, it's been known to cause hesitation when shifting at high RPM.

I ended up going with a BBK 320 lph fuel hat & pump because I didn't want to mess with the lines or soldering. The hat is basically identical to stock, but it doesn't have the PPRV valve. The fuel lines looked a little thicker and felt more flexible than OEM but other than that it looked identical to my stock pump & hat.

Here is mine I believe:
BBK Mustang Direct Replacement Fuel Pump 1862 (99-00 All)
When I bought it a couple years ago, it was rated at 320 lph and it was also like $300 I believe. They specify another model for your 01 Cobra so make sure you get the right one.

It's been flawless for me, I noticed an improvement in throttle response and my car ran smoother. It dropped right in and I haven't had a single issue in over 2 years of somewhat aggressive weekend driving, also including 3 hour drives to the beach and back.

I've read BBK has issues with their header quality, and their expensive throttle body is basically useless... but my experience with this fuel pump & hat is very positive. It installed just like stock, and was plug & play. Just as quiet or quieter than my stock pump also. No issues whatsoever and I'm happy with it.

Glad to hear your car runs fine on a 320lph pump. Ive read that you can only go so high on a stock tune (as the computer was tuned for the flow characteristics of the stock pump). I guess you dispelled that.

 

[01yellercobra]

I bought the pumps off eBay from Brenspeed. They were take outs from a 07-09 GT500. The part numbers on the pumps match the SVT Focus pump and they have green tops as well. They look identical to the SVTF pump I used to own. Only reason for going with them is the car supposedly has SVTF pumps already with an 03/04 hat so its just easier to stick with them. Plus the car will have a fuel system that's ready for boost later on.

Ive yet to take the tank down, hoping to get to it this weekend. Ill post my findings when the time comes.

That's good info. You'll have to post up what you find for people searching in the future.

 

[2000GTSTANG]

That's good info. You'll have to post up what you find for people searching in the future.

Definitely will do!

 

[decipha]

if the car is stock why not stuff a stock pump back in it?

I DO NOT RECOMMEND GETTING RID OF THE PPRV!!!!

without the pprv you could potentially damage the engine from over fueling if the frps ever goes bad or even best case the vehicle is not drive-able if you catch it in time.

henry wouldn't have spent 30 million dollars on the pprv if it wasn't needed

if your fuel pump shuts off on the shifts just get your tuner to leave the pump on for 2 seconds after wot

 

[2000GTSTANG]

if the car is stock why not stuff a stock pump back in it?

I DO NOT RECOMMEND GETTING RID OF THE PPRV!!!!

without the pprv you could potentially damage the engine from over fueling if the frps ever goes bad or even best case the vehicle is not drive-able if you catch it in time.

henry wouldn't have spent 30 million dollars on the pprv if it wasn't needed

if your fuel pump shuts off on the shifts just get your tuner to leave the pump on for 2 seconds after wot

I normally would but the car has a built engine and may or may not get boosted again in the future.

 

[2000GTSTANG]

Fixed the low pressure issue this evening! Pulled the tank, discovered two corroded mismatched pumps. Not really sure which ones they are; I'll have to try to read the part numbers later but it looks like a stock fuel pump and an SVTF pump. The tank inside looks beautiful, unfortunately its the stock 01 tank but I can deal with that.

I decided to use the stock 03-04 pump socks since they were in good shape and were pretty clean.

The 07-09 GT500 pumps went right in, obviously this would have required some modifications from me if the hat had the stock Terminator pump wiring on it.

Untitled by michiganz, on Flickr

Untitled by michiganz, on Flickr

Untitled by michiganz, on Flickr

Untitled by michiganz, on Flickr

 

[01yellercobra]

If it is the stock 01 tank make sure to keep the fuel level above quarter tank. Don't want those pumps coming uncovered.

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[2000GTSTANG]

If it is the stock 01 tank make sure to keep the fuel level above quarter tank. Don't want those pumps coming uncovered.

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Oh yeah im well aware of that.