fpdc fuel issue! leaning

Hi long time without posting in this forum, i have a stroked and paxton supercharged mustang. im having an issue with the fpdc maxing out, i have the cobra dual hat, the car was running ok but suddenly the fpdc started to climb i can't floor it because it goes to .50 (100%) under boost i changed both pumps, all the filters, and the problem is still there, its there any way i can test each FPDM?

thank you so much and sorry for my bad english..

Yes, start the car and let it idle. Unplug one fpdm at a time this will effectively test that fpdm and pump as it will shut off the corresponding pump. The car should still be able to run with one bank/pump disconnected. If you uplug one and the car dies then problem is likely with the other one that's still plugged in. To the test for each side and see what happens.

What power, boost level, injector size, tuner? Has the fuel system previously performed on this setup with out pegging? How long has it been on the car?

What is fuel pressure doing when duty cycle pegs is it dropping as well or staying solid? this is the real tell to know when pumps are truly maxed, they will be unable to maintain delta pressure.

When you say all filters, did you replace the inline filter under the car as well?

i have a 5.1 stroker 9.4 compression ratio, paxton novi 2200 2.87 pulley tuned by lito, lu47 injectors, i changed the inline filter, and the pumps filter, i tried new pumps and the problem its still there, .50fpdm, i tested each module en idle the fpdm climbed to .28 on one fpdm at the time and .24 with both.

the problem started with the smaller injectors and 3.33 pulley i tought it was the injectors clogged or a filter, so i made the pulley, injectors, filters swap and the problem its still there, the car ran flawlessly for years... it remained stored for about 8 months when i noticed the problem

What boost/power level? And most important what is fuel pressure doing when you see the .50 duty cycle? Whats lito's take on it? If you have a data log to post that would help as well. Any codes? Another issue I have seen is guys scrape up the corrugated hose on the hat when it goes in and out of the tank which can weaken it, over time with pressure cycles it can leak and bleed pressure in the hat and cause the pumps to max out early.

# I had my FPDC increase to 96% (48 on the aeroforce gauges). Then installed the 10 gauge wire mod from battery to pump. FPDC got even worse, 98% (49 on the gauge) . Installed new fuel filter, zero change. Long story short, ran fine on the hwy and around town, BUT.. it would gag whenever I tried to get into boost.... even a little bit. Problem turned out to be a clogged oem sock filter. Once that was cleaned out, FPDC dropped to 78-80% at WOT... @ 6k rpm. Mine was the 8th stang in town with a clogged sock filter. The only thing in common was we all used Chevron 94 octane fuel.

ouch dirty fuel there Pentalab!

Yup our fuel in Canada has been getting dirtier and dirtier the 94 we once had is no longer 94 once Petro Canada bought it over...

06monera96 said:

ouch dirty fuel there Pentalab!

Yup our fuel in Canada has been getting dirtier and dirtier the 94 we once had is no longer 94 once Petro Canada bought it over...

Click to expand...

We only have one oil refinery in BC..and that's down by the waterfront in Burnaby. Owned by Chevron since the early 20's. So whether you buy gas from shell, petrocan, costco, esso, or anywhere else, it all originated from the same refinery.

Everybody else sells just 87-89-91 (with up to 10% ethanol). Only Chevron sells 94 octane...and it doesn't have any ethanol in it. We almost need some kind of external filter, b4 it even gets into the car. I could see more crap floating about the bottom, that was with just under 1/4 tank, when we pulled the entire fuel pump out to clean the sock filter. Then you have the other tank on the pass side. Fuel pump is on the driver's side on my 2010.

91 octane + 0-10% ethanol doesn't cut it performance wise, but at least it's readily available anywhere. 94 from chevron is only available in the lower mainland area..and the east side of Vancouver island. My current tune is tweaked for 94 + no ethanol. At least when I see the fpdc creeping up on the aeroforce, I know the sock filter is starting to clog again.

I bought some new sock filters here in town, but they are smaller than oem, even though they fit. I can't use em with my small blower setup, they barely work on a NA setup. The oem sock filters are easy enough to clean out, but a pita to get that pump in and out.