Gas gauge goes to zero randomly w/ FRPP 750 kit.

[jchristena]

So, the FRPP 750 kit comes w/ the new fuel hat that has the Walbros. That's a different thread on whether those suck or not. Anyway, everything is working ok, but I went on a few hundred mile drive this weekend and somethings screwed. I looked at my gas gauge an it was right on 1/2 a tank. This was about right considering how far I had driven. All of a sudden, the gauge drops to zero and the computer says 3 miles til empty. Just because I had a ways to go and no gauge I filled up a few min later. It only held took about 7 gallons. On my trip home, once again about 1/2 a tank, it dropped to zero and said 3 miles left. WTF. I mean, the float and all that is part of the new hat. Any ideas? Im about ready just to shove the stock hat back in. Wish it wasn't such a pain in the arse to do.

Thanks

 

[stkjock]

I bet it's the float/float arm or sending unit.

 

[dirtyo2000]

Sounds like it may have bent the arm on installation. Run it down to E and pull it out. I hate the gas smell

 

[Tob]

The float arm can get caught up on one of the pump connectors. Click on the FRPP/Whipple writeup in my sig. Scroll through it until you come to the pump portion. You'll see it there...

 

[fullboogie]

Isn't there also a problem with the transfer tube coming loose or becoming kinked? If so, that won't allow the passenger side tank to transfer to the driver's side, giving funky fuel level readings.

 

[me32]

Isn't there also a problem with the transfer tube coming loose or becoming kinked? If so, that won't allow the passenger side tank to transfer to the driver's side, giving funky fuel level readings.

I had this exact same issues an it end up something very very small got stuck in the tube which cause me only to be able to use the driver side tank.

 

[Goose17]

Wrestling the 10 pound fuel pump through the 5 pound hole is not fun. I'm sure you bent something going in. Like stated above, run tank down and pull out the unit and have a look-see.

 

[GT Premi]

Like others said, it's one of two things. Either you bent the arm (it's really flimsy) or the float is hung up on something. You need to be REALLY careful while installing the pump. You can't just jam it in the hole. It has to be wiggled and finessed and twisted. It's really not that bad to do. I'm betting the float is bound up on the fuel tube.

 

[jchristena]

Well, the thing is, it was inconsistent. Sometimes it would be fine. I emailed FRPP tech support. They are always super responsive. The guy said that it is common w/ the new fuel hat(the float arm is not the same as stock when you compare them) for the float to hit the baffle and ground itself. He said take a wooden dowl and lean on the baffle for clearance. Would have been nice to know this on the first install.

But, it looks like there was a different problem. There are two plastic pieces that snap together in the middle of the pump assembly. Not sure what part that is, but it is where the black plastic connector snaps in, in the middle of assembly. Those two pieces had become separated. Still, given the issue with the float possibly hitting the baffle, and the discussion of stock vs. Walbro, I just shoved the stock assembly back in and will order a BAP today.

So, the next question, which BAP?

Brenspeed sells this one and it says for dual pumps:
40 amp Kenne Bell boost a pump for dual pumps

But, it would appear that the car needs the 89064. Can anyone confirm this is the correct one?
Kenne Bell GT500 Dual Boost-A-Pump (Supercharged) [KB89064] - $469.00 : Evolution Performance, Performance Parts & Accessories - Ford Mustang & Shelby Experts

Thanks guys.

 

[fullboogie]

The one sold by Brenspeed is not for the GT500. You need the second one you listed.

 

[jchristena]

Thanks. Is the install the same as on my 5.0? I remember it being the purple wire on with the green stripe. Also, I assume on the GT500 it is also the norm to hard wire to always max? Is there a write up anyone has done? Thanks again.

 

[466scj]

I went thru the same problem and took months to figure out.At first,the pump was shipped without the long white plastic piece that snaps on with a rubber plug on the end.It has a small slit on the bottom.P.M. me for pics of it.Ford racing sent me the piece.I installed it and still had the same problem.I tried everything they suggested.I got pretty good at removing the pumps,could do it in 5 mins.After checking for kinked,plugged transfer tube,correct sending unit,wiring,it turned out to be the cone shaped part the long white piece snaps onto.It is supposed to have a hole in the center to siphon fuel from the passenger tank.Your transfer tube for the other side connects to this cone shaped piece with the hole in the center,that the long piece snaps onto.The pump was sent with no hole on the center of the cone shaped part and the long piece that causes suction to siphon from the passenger side.Please feel free to P.M. me your email address and i can send you a pic of the parts i am refering to.

 

[466scj]

BTW,what it is doing is not emptying the passenger side saddle of the tank.It only empties the drivers side,gauge reads 1/2 full and when it is empty,it drops to empty with 3 miles to 0.Pull the lid on the passenger side and see if it is full when it says empty.Ray at Ford racing was very helpful,but took forever to figure out.

 

[LizardGT500]

Had some issues with the gas level on full tank. Indicator would randomly go to empty and give an error message. But as soon as passenger side was empty it would operate as normal. So I assume it sender unit grounds it self intermittently when the tank is full.
But the problem I've faced yesterday is a bit more sad. Car just died and wouldn't start. 0 psi on the fuel rail. Check voltages on both pumps are present. Pulled the pump unit out and took it apart. Both pumps run but main does not pump. Took it apart and found that plastic joint that connects the motor and the actual displacement unit is twisted and broken. So the pump is Walbro GSS342 and i bought it for $64 on eBay. The thing is that I only get it in a couple of weeks but I need the car running now. What would be the safest way of temporarily getting it back on road? Swap the walbro main and aux pumps, they are identical, or plug the OEM pump in? I am not going to floor it, just need a ride. Power mods only FRPP 725hp kit car, 2009 gt500

 

[LizardGT500]

Had some issues with the gas level on full tank. Indicator would randomly go to empty and give an error message. But as soon as passenger side was empty it would operate as normal. So I assume it sender unit grounds it self intermittently when the tank is full.
But the problem I've faced yesterday is a bit more sad. Car just died and wouldn't start. 0 psi on the fuel rail. Check voltages on both pumps are present. Pulled the pump unit out and took it apart. Both pumps run but main does not pump. Took it apart and found that plastic joint that connects the motor and the actual displacement unit is twisted and broken. So the pump is Walbro GSS342 and i bought it for $64 on eBay. The thing is that I only get it in a couple of weeks but I need the car running now. What would be the safest way of temporarily getting it back on road? Swap the walbro main and aux pumps, they are identical, or plug the OEM pump in? I am not going to floor it, just need a ride. Power mods only FRPP 725hp kit car, 2009 gt500

Some update
So I've just swap the pumps main and aux and installed the unit back. As soon as I've turned the key the fuel pressure built up. I've started the car, it run for about 5 seconds,pressure dropped and it stalled again. While trying to restart it I've heard the familiar idling pum noise but no pressure on a fuel rail. So I though the second pump is dead and pulled the unit out again. What a surprise it was for me but the second pump was still OK. The conclusion is there is no main or aux pump. PCM continuously change them and as soon as one fails, it remembers it and tries to start the engine with same pump.
Now the question is, is it safe to run the car with this setup but using the stock pump?