Bypassing / Eliminating 2012 5.3 Liter Fuel Pump Control Module E38 Computer

[dave w]

I'm wondering if anyone knows how to bypass or eliminate the fuel pump control module for a 2012 E38 computer. The project is an older Jeep that is getting an engine / trans / t-case from a 2012 GM 4WD pickup 5.3 liter.

Thanks for any information / ideas.

dave w

Fuel Pump Control Module

Fuel Pump Flow Control Module (FPCM) – LMF
The fuel pump flow control module (FPCM) is a serviceable GMLAN module. The FPCM receives the desired fuel pressure message from the engine control module (ECM) and controls the fuel pump located within the fuel tank to achieve the desired fuel pressure. The FPCM sends a 25 KHZ PWM signal to the fuel pump, and pump speed is changed by varying the duty cycle of this signal. Maximum current supplied to the fuel pump is 15 amps. A liquid fuel pressure sensor provides fuel pressure feedback to the FPCM.

Electronic Returnless Fuel System (ERFS) – LMF
The electronic returnless fuel system is a microprocessor controlled fuel delivery system which transports fuel from the tank to the fuel rails. It functions as an electronic replacement for a traditional, mechanical fuel pressure regulator. A pressure vent valve within the fuel tank provides an added measure of fuel pump flow control module (FPCM). Desired fuel pressure is commanded by the engine control module (ECM), and transmitted to the FPCM via a GMLAN serial data message. A liquid fuel pressure sensor provides the feedback the FPCM requires for Closed Loop fuel pressure control.

Liquid Fuel Pressure Sensor – With FPCM
The fuel pressure sensor is a serviceable 5-volt, 3-pin device. It is located on the fuel feed line forward of the fuel tank, and receives power and ground from the fuel pump flow control module (FPCM) through a vehicle wiring harness. The sensor provides a fuel pressure signal to the FPCM, which is used to provide Closed Loop fuel pressure control.

[RobertISaar]

how complex do you want to get? what PCM do you plan on running?

[dave w]

how complex do you want to get? what PCM do you plan on running?

It's the E38 Computer. See attached pic.

I'd like simple, maybe an external fuel pressure regulator and return line instead of the returnless system that was original to the 2012 model year. I don't think that is an option? Maybe the solution is a custom built fuel cell to incorporate all the fuel system features from the 2012 model year donor vehicle.

dave

[dave w]

It seems I'm in the middle of a real challenge. The 2012 is already installed into a 2009 Jeep Wrangler 4 door. I'm thinking I'll need to investigate the option of using the GM 5.3 liter fuel pump control module with the Jeep fuel pump and Jeep fuel tank. The 2009 Jeep Wrangler 4 door uses a returnless fuel system similar to the 2012 GM pickup.

dave w

[lionelhutz]

You should be able to run the Jeep pump (or almost any typical pump) from the module, assuming it will create enough pressure and flow. Can the fuel pressure sensor be mounted on the engine or in the line somehow fairly easily?

It sounds like the tank has another mechanical over pressure valve/regulator. The Jeep might have something similar.

[EagleMark]

Just things to think about... with returnless system it is PWM and somewhere needs a dampener. Does Jeep system have this. Truthfully I don't even know where or how it works on GM but dampener is part of how system stays steady pressure instead of jumpy...

[JeepsAndGuns]

I tried searching, but didnt find much. I did find this site:
http://www.dtcresq1.com/resq1-part-4...inues-443.html

They mention using the stock JK fuel pump, but adding a larger line.

[EagleMark]

Although I would not like rubber line from tank to engine... especially in an off roader! But the rubber line would be all the dampening needed.

The FAST EZ 2.0 system will do return less and mentions the dampener is part of or it is the fuel line.

[JeepsAndGuns]

My 99 grand cherokee is returnless and the dampner is in the fuel rail, as with all other late model 4.0.
Not sure about the V6's or V8's.

[dave w]

I like all the information I'm getting!

I'll do some research with AllData.

dave w

[Caleditor]

Dave I change them back and forth often.
What brand of software are you using?

E38 on a 60 deg V6 uses a regular pump and the 5.3L will use the FPCM.

You will see a setting to change pump type. Let me now what you are using and I will look up the settings for you and post them.

[JeepsAndGuns]

Although I would not like rubber line from tank to engine... especially in an off roader! But the rubber line would be all the dampening needed.

I'm sure some new hard line could be bent up and mounted to the frame without too much trouble. I did it on my cherokee. I just used regular brake line.

[Caleditor]

I got EFILive open today.

laptop just got me with this post. I hit space and it posted the first line

look at F0585

Sorry about all of the files, but I can not see all of the details in my folders currently

[Montecarlodrag]

It can be done.
Delete the FPCM and all it's wiring, install a return fuel system and set pressure to 58 PSI.
You need several tune changes but engine runs with stock tune. I have done a few swaps and deleted the FPCM to all of them, too much hassle

[Caleditor]

To the other question
The returnless fuel system that is used on the Impala's without the FPCM has a fuel pressure regulator. I think I have a 2011 Impala fuel pump in the garage from one of the Impala's I converted to run on CNG. I can take a picture if you would like or even send it to you. I have no use for it if I still have it.

In the end I would not think that the placement of the regulator does not matter. I would not use vacuum to change the pressure. It may take some additional tuning

2008 Chevrolet Impala | Impala VIN W Service Manual | Engine | Engine Controls and Fuel - 3.9L | Description and Operation |
Document ID: 1737023


Fuel System Description
Fuel System Overview
The fuel system is a returnless on-demand design. The fuel pressure regulator is a part of the fuel sender assembly, eliminating the need for a return pipe from the engine. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions.
The fuel tank stores the fuel supply. An electric turbine style fuel pump attaches to the fuel sender assembly inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel filter contained in the fuel sender assembly and the fuel feed pipe to the Fuel Injection System. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pump also supplies fuel to a venturi pump located on the bottom of the fuel sender assembly. The function of the venturi pump is to fill the fuel sender assembly reservoir. The fuel pressure regulator, a part of the fuel sender assembly, maintains the correct fuel pressure to the fuel injection system. The fuel pump and sender assembly contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cracking times.