Ludo

Hello everyone
I have a question about the FPDM.
On my 2007 truck I wanted to replace my fpdm preemptively. The old module worked perfectly. But it was in bad shape and I hate the idea of ​​being out of order.
Before the replacement, the key on engine off the pressure was 350 KPA at the time of engine start the pressure dropped to 220 kpa for 1 second and stabilize at 270KPA while driving.
With the new FPDM. key on engine off. the pressure and 500KPA. At the moment I but the engine running the pressure drops to 150 kpa for 1 second. Which coughs the engine once. Then, during stable driving, the pressure stabilizes at 270 kpa. At the moment of acceleration the pressure falls to 160 kpa and directly it rises to 350KPA.
Is it normal to have such a large pressure difference? Or is the new FPDM in error?
Any help is appreciated.

F150Torqued

Frankly, I like the readings from your old one better than the new one. (you may know all this, but) To make a 'returnless' system while providing injectors proper differential pressure across injectors (input to spray nozzle sitting in a negative pressure), the FRP sensor reads fuel pressure "RELATIVE" to intake manifold vacuum. That signal is sent to FPDM who, adjusts its square wave % duty cycle voltage to the fuel pump to drive it harder or lighter (as needed) in a 'closed loop' system.

I can understand some lag, or delay in the electronics settling down. In fact I suspect the operation could benefit from some 'hysteresis' to avoid 'oscillation'. But Gezzz, that knew one is slow as hell.

techrep

iTrader: (1)

Ludo

No. Spectra premium.
What is the best brand?

F150Torqued

Can't say as I have necessary expertise to comment on it. My 242,000 mile truck is still running on the original one.

But since you use Torque Pro - thought a quick comparison check on my truck might give you more clues. First screenshot is KOEO. Second is KOER. (Curious why the "BOOST" gauge (which will read either turbo boost - or vacuum, shows 30 Inhg vacuum at KOEO ???).


FPDC and FRP at KOEO

FPDC and FRP at KOER

Ludo

Hello.
It's strange in my torquepro application I can not find the fuel pressure work cycle (FPDC).
On the other hand when I am in position KOEO My gauge of boost will indicate 0 ing.
And in KOER close to your information.
By cons KOEO position my fuel pressure is higher. And in position KOER my fuel pressure and lower than your reading.

Ludo

I just checked the work cycle with forscan. Cold engine: KOEO 75% KOER 15% at 600 RPM.
Hot engine: KOEO 75% the first second that follows the start the percentage fluctuates without stopping between 15% and 75%.

F150Torqued

Sorry, Fuel Pump Duty Cycle is a custom PID that I have 'dug up' through my research. Don't think it is part of Torque Pro's extended PID set for Ford. I always put an underscore character "_" in front of MY custom pids so they sort to front of the list and keep them separated from Torque's.

Mode/PID: 221672
Long Name: _Fuel Pump Duty Cycle
Short Nm: FPDC
Min/Max 0 / 100
Unit: %
Equation: (A*256+B)* (100/32767)
Header: Auto
Diag St/Stop: blank

Ludo

Oh ok. You do not find it strange that the value fluctuates more than once between 15% and 75% at startup. After a pause of a few minutes.

Ludo

I think I will order a new one. Just before the replacement the trucks had no problem. I just replaced the FPDM for security