Team Chepsk8

As usual, trying to understand how the systems work. What is the exact purpose of the module? Current limiting? Varies speed with demand? Does it replace the fuel regulator?

And, since these things die by the gazillions, can a by-pass plug be made up, or wires temporarily spliced to get out of a bad jam?

SCORGE

The Fuel Pump Driver Module communicates diagnostic information to the powertrain control module (PCM) through the Fuel Pump Monitor (FPM) circuit. This information is sent by the FPDM as a duty cycle signal which in turns controls the fuel pump.
What my Bing search revealed. Seems to be a monitor of sorts.

redfishtd

No return line to dump excess fuel from regulator. Saving energy and using no regulator or return line to tank so its cheaper to build . plus it includes shutdown of pump for safety reasons . The most frequent failure is no fuel . The alum back plate mounted directly to steel axle with added salt /water speeds up eletrolisis . The fix was to mount it on stand offs to prevent direct contact and build up of contaminants between the joint .
Fuel pressure on demand allows the fuel rail pressure sensor on fuel rail to shut on/off fuel as needed due to load speed etc . but has to have permission from pcm and safety systems feeding pcm .
I suspect fuel rail sensor would not handle load of pump by itself and would be a trap in an accident . Having fuel being pumped out while trapped inside is not a good thing . I'm sure there are other scenarios that the pcm covers . I realize that the inertia switch still backs up shutting power to pump off . The pcm looks at many things to signal fuel pressure demand module .
The worst thing they did was to remove schrader valve from fuel rail, makes it hard to check pressure . .

Eric Kleven

Variable speed driver, varies pump speed with fuel demand, ECM tries to match fuel rail pressure -vs- intake manifold pressure to act as a 'virtual fuel pressure regulator'.

re: bypass, yes, but I don't remember which ones to jumper, and i hear tell it will blow a fuse when you shut the vehicle off.
-the bypass may have been done with a 30-amp fuse, and that would likely blow when the truck is shut off. Any monitoring I've done, the pump duty cycle is around 20% for normal driving, jumpering would drive a LOT of fuel pressure into the rail. ECM can adjust injectors, but pressure is still pressure.

techrep

iTrader: (1)

gone postal

Now that its a known problem and easily remedied, no real need for a workaround. If you're worried about it, keep a spare module in the glove box with a 10mm wrench. They're less troublesome than duraspark modules, no big deal now, really.

When it was a new problem and they were dying and FoMoCo didn't have any replacements? THEN it was an issue.....2 months to get a replacement module for my truck I was still paying for...