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Testing lift pump pressure.

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Old 12-12-2016, 10:15 AM
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Testing lift pump pressure.

I'd like to check the health of my lift pump to see if it's contributing to my fuel system issues.

Flow and pressure.

Can someone outline this procedure? I understand you need a special banjo fitting going to the CP3 to test pressure? Does anyone have a Cummins part # for this fitting?
Old 12-12-2016, 02:47 PM
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Open bottom of the fuel filter housing. Turn the truck on and you should get about 1 quart of fuel in 20 seconds.
Old 12-13-2016, 06:45 AM
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Ahh, just out of the water tap drain you mean?

Simple, never thought of that.
Old 12-13-2016, 08:43 AM
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Correct
Old 04-30-2017, 08:29 PM
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This project has been on hold this winter. I even drove a F*rd most of the time.
I went ahead, drained the fuel filter housing and put a 2 litre jug under the open drain hose.

Bumped the key and found that i got only about 600 mls of fuel letting the lift pump run for the whole 25 seconds.

Seems this isnt enough fuel? I read that you should get 500+ mls in 10 seconds?

Bad lift pump?

I can'tcan't find anyone with a tapped Banjo bolt locally, how have others jerry rigged a lift pump pressurre set up?
Old 05-01-2017, 01:13 AM
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Originally Posted by tool
This project has been on hold this winter. I even drove a F*rd most of the time.
I went ahead, drained the fuel filter housing and put a 2 litre jug under the open drain hose.

Bumped the key and found that i got only about 600 mls of fuel letting the lift pump run for the whole 25 seconds.

Seems this isnt enough fuel? I read that you should get 500+ mls in 10 seconds?

Bad lift pump?

I can'tcan't find anyone with a tapped Banjo bolt locally, how have others jerry rigged a lift pump pressurre set up?
I just had a bit of a brain fart, why couldn't I just clamp a hose to the bottom of the filter drain and run it up to the windshield and onto my pressure gauge and leave the drain open. That should work i think.
Old 05-01-2017, 05:35 AM
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On my truck there is quite a hefty steel elbow coming right off the CP3. I drilled and tapped that for a 1/8" fitting and tied my gauge into that. This has been working trouble free for many years.

If you feed a metal line directly into the cab then you may discover that this transmits noise. Two solutions that I discovered. Switch to a non-metallic line plus install a snubber right at the pump. Snubbers are very easy to make. The non-metallic line that I use is from Parker and is rated at 300 psi and is diesel proof. Of course you can also use an electric gauge and then just run some wires into the cab.
Old 05-01-2017, 08:43 PM
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I'm not looking to install a permanent gauge at this point, just rigging something up for diagnostics.
I had a setup thay i rigged up for checking my VP44 truck periodically but those are sumple because of the fitting on top of the filter housing.
Old 05-12-2017, 10:57 PM
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Just to follow up on this in case someone else has this problem, yes you can test your FP from the filter drain. Just clamp a 1/3" ID onto the filter drain and attach your gauge.

I found that I had only 3 psi at idle and zero with any load.
I replaced the lift pump unit and I'm back to 15 psi at idle and 10 or so under load.
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