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Unread 01-27-2013, 07:15 PM   #1
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ronjenx's Avatar
2008 JK Wrangler 
Join Date: Jan 2009
Location: Maine
Posts: 4,295
OEM Fuel Pump Module Study

The fuel filters for the JK are in the fuel pump module, and are listed as "not serviced",
which means they can't be changed without replacing the entire fuel pump module.
The same goes for the fuel pump and the pressure regulator.
I have not seen any forum traffic about the filters being the source of problems.
Here are some pictures to show how this is all put together.

1. Here is a view of the fuel pump module.
The top cover is what is clamped to the top of the tank.
The spring holds the fuel reservoir down onto the bottom of the tank.

2. This is a close-up of the fuel lever sensor.
There are two contacts that sweep up and down on the sensor board.

3. Here you can see the discharge filter/pump sitting in the reservoir.
What is visible is actually the discharge filter container.
The pump is in the center of the filter.
Some of the pressurized fuel is tapped off to be shot from a nozzle,
through a flapper type check valve, and into the bottom of the reservoir.
As the fuel is shot in, it brings fuel from the tank into the reservoir with it.
This keeps the reservoir full, ensuring a good supply of fuel for the pump to draw from,
even when the fuel level in the tank is below the top of the reservoir.
The jet of fuel may also create a swirling effect in the bottom of the reservoir which
keeps the surface of inlet filter clean.
It also ensures the pump is constantly bathed in "cool fuel", at least until the very end of the supply.

4. A look at the flapper valve in the bottom of the reservoir.
Fuel can check in, but it can never leave, (except through the pump).

5. Here is the pump/discharge filter housing. You can see the inlet filter at the bottom.
The pressure regulator is to the lower left.
Anything over 58 ±2 psi is dumped through the outlet at the bottom of the regulator, into the reservoir.
The large black line carries fuel out of the tank, and on to the fuel rail on the engine.
The little black line routes some of the pressurized fuel to the jet nozzle,
where it is sprayed into the bottom of the reservoir, bringing fuel from the tank with it.
This keeps the reservoir full.

6. Here is a view of the pump, inlet filter, and discharge port.

7. This is the discharge filter housing, upside down to show where the pump discharge port connects.
As you can see, the pressure regulator housing is molded into the filter housing.

This pump module is very easy to disassemble, change the parts, and reassemble.
As far as I know, there is no parts support. So, if anything needs replacing, the entire module must be changed.
I think an access panel should have been made in the tub floor so the module could be removed without draining and removing the tank.
I have seen that in other vehicles.

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Unread 01-27-2013, 09:11 PM   #2
Make mine a Jeep!
1222's Avatar
2012 JK Wrangler 
Join Date: Jul 2007
Location: Henderson, Nevada
Posts: 12,776
Excellent write-up and pics as always.

Too bad your Jeep is incapacitated at the moment.
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Unread 01-27-2013, 09:37 PM   #3
What was I thinking?
JLC08JK's Avatar
2008 JK Wrangler 
Join Date: Sep 2009
Location: Los Angeles, California
Posts: 5,987
Another great "Study" added to the F.A.Q.
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Unread 01-27-2013, 10:25 PM   #4
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2012 JK Wrangler 
Join Date: Jan 2007
Location: West Haven, UT
Posts: 2,033
Great information! That answered most of my questions about the filter...I also didn't know the fuel pressure regulator is included as well (that's another thing I don't like about it).
Utah Jeep Crew #148
No powerball here? How am I supposed to finance the mods?!?
'12 Sport...miss my YJ for all the wrong reasons though
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Unread 02-02-2013, 08:56 AM   #5
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2007 JK Wrangler 
Join Date: Jun 2010
Location: Reno, Nevada
Posts: 713
Thanks for posting.
If you learned something new today, you had a good day.
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Unread 02-03-2013, 04:29 AM   #6
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2011 JK Wrangler 
Join Date: Jun 2011
Posts: 3,007
Awesome job once again, Ronjenx! Interesting stuff.
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