Inline fuel pump in CRD -06 engine bay

What, not a Beamer? · **Joined:** Mon Jan 28, 2019 3:54 pm **Posts:** 13

I'm planning to add a small inline fuel pump in engine bay to improve cold starts etc. Pump would be low pressure (0,3 bar) solenoid/piston type one. Engine bay version due to not really keen on tank lift kit for excessive work related.

There are couple of other threads related to this, but they are focused on piping, which seems trivial. Wiring instead does not seem to be so easy in CRD.

Should the pump run in both START+RUN positions, or only in RUN-position?
Where should I take the power for the pump?
Where should I take the control for the pump (assuming that I will install a relay)?
Should I install also an inertia switch, or rely on power wired via the ASD relay, or something else to stop the pump in case of an accident?

And please don't refer to existing fuel pump relay - there is none. Instead the socket is used for diesel pre-heater relay.

At the moment my plan is to:
- take the power for the pump from ASD relay output after fuse 26 (25A) in power distribution center,
- add a relay, and take the control from RUN-START-position output F944 after fuse 14 (10A) in junction box,
- and just to be safe add also an inertia switch in the power line.

Better instructions, comments, proposals, all wellcome. Please.

My66dodge · **Posted:** Sat Jan 16, 2021 9:55 am

Just get the harness from Sasquatch parts and drop in 06 Cummins pump in the tank easiest way to do it

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What, not a Beamer? · **Joined:** Mon Jan 28, 2019 3:54 pm **Posts:** 13

Nope, I won't. Its too much work and too expensive for the old car. I also don't think that the harness would work without some modification, as there is no fuel pump relay, and the control for the replacing fuel heater relay is different from fuel pump's one. I haven't dug out when this was changed, but I suspect in facelift 2006-2007.

My66dodge · **Posted:** Sat Jan 16, 2021 12:54 pm

I’m afraid you were gravely mistaken there is a fuel pump relay and fuse already under the hood the wiring is complete up until the backseat if you lift up the carpet and take out the backseat on the driver side you will find the power for the fuel pump already in the harness connector so the harness from Sasquatch is the same harness you have going from under the backseat to both rear wheel speed sensors and to the fuel sending unit only they added the wiring for the fuel pump so it goes from under the backseat To the pump you’re putting in if you’re looking to do it for cheaper just get a V-6 rear harness from the junkyard that’s what I did on my wife’s jeep then all you need to do is switch to Pinz at the back seat harness because they run the level send her in a different spot on the V-6 harness as they do the diesel but all harnesses are the same from the engine bay to the backseat

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turblediesel · **Posted:** Sat Jan 16, 2021 1:02 pm

Somewhere on the forum is all the info you're looking for. My parts jeep came with an inline pump installed. I'll check and see if I can find it and a part number for you. I do remember Facet makes them and you want one that will allow fuel to flow through when it fails.

PZKW108 · **Joined:** Sun Apr 06, 2014 5:23 pm **Posts:** 461

What, not a Beamer? wrote:

Nope, I won't. Its too much work and too expensive for the old car. I also don't think that the harness would work without some modification, as there is no fuel pump relay, and the control for the replacing fuel heater relay is different from fuel pump's one. I haven't dug out when this was changed, but I suspect in facelift 2006-2007.

It's mostly the air drawn in the system that makes for delayed start, the inline pump won't fix that.

In-tank lift pump is the way to go, and the missing harness is really easy to do by yourself !

WWDiesel · **Posted:** Sat Jan 16, 2021 1:52 pm

Just as others are telling you, all the wiring along with the fuel pump relay comes in place from the factory and terminates in a connector under the left rear seat.
The logic for running the fuel pump is also in place from the factory. The ECM controls the fuel pump relay perfectly. Runs for ~15-20 seconds when you bump the starter motor and runs continuously anytime the engine is running.
The VERY BEST option is to drop the fuel tank and install the fuel tank module with the fuel pump inside the tank. This puts everything under ~14 psig pressure all the way from inside the fuel tank to the back of the CP3 injection pump.
Install the intank fuel pump module and add the wiring (2 wires) from the connector under the rear seat to the top of the fuel tank and you are done for good.
Although an inline pump will work, the problem with them is if there is any leak anywhere on the suction side of the pump, it will still suck air into the fuel system and cause running problems due to air infusion.

See these links for in-tank fuel pump install procedures:> http://www.auerbach.ca/kj/lift_pump/default.html

Wiring ends from Mouser Electronics:> https://www.mouser.com/Connectors/Autom ... bwZ1z1414h

turblediesel · **Posted:** Sat Jan 16, 2021 7:42 pm

Looked at my parts jeep and here's the info:

Facet Posi-flo EFP-3 universal electric fuel pump

One wire goes to battery ground and the other
wire goes to the fuel priming pump relay #5 pin
(as marked on the relay). It's the most central pin,
one of two pins oriented one way; the other three
pins are perpendicular.

I agree with what everyone else is saying about the
in-tank pump being the best solution.

What, not a Beamer? · **Joined:** Mon Jan 28, 2019 3:54 pm **Posts:** 13

Hi,

and many thanks for the advice.

I understand and totally agree that the in-tank lift pump would be the best option. Still I hope that the engine bay solution would be good enough for me. My problem is not intermittent air and consequent running issues, so the lines seem to be OK still. The problem is cold weather and diesel getting thick under -15C - causing slow starts and/or these 15 second engine runs and stops in the startup. I suppose that the CP3 draws a vacuum in the line rather than air, and when the fuel slowly passes the filter it starts again after a while. Just a theory, no real proof apart from symptoms. No running issues whatsoever in normal ambient.

I need to check if my CRD has the fuel pump wiring also under the back seat as you all seem to be very convinced about that. My claim of it missing was based on the service manual wiring diagrams, but of course it is possible that there is a wiring which has not been documented due to omitting the pump in the production versions. The relay that I have in the gas versions' fuel pump relay socket certainly controls the fuel heater. I suppose that the heater and pump should not be connected in parallel for obvious reasons, so the pump power must come from another source. Maybe directly from ECM? Has anyone traced the pump power line under the seat back to junction box or engine bay? If I have that, then that would be of course the first and easiest choice for wiring. Especially If I find it in the engine bay...

Other reasons for my stubborn attempt are that I already happen to have a suitable low pressure suction type pump available (Huco 13 3010) which I bought some time ago for another project, and that the lift pump kit and harness don't seem to be available in Europe. Ordering from US would cost me ~800 USD after tolls and taxes. So I want to avoid it if possible.

WWDiesel · **Posted:** Mon Jan 18, 2021 1:52 pm

Maybe these wiring diagrams and picture of an actual 05 Power Distribution Panel will help you understand how the Jeep CRD is wired for the in-tank fuel pump from the factory? Keep in mind, the WD's are adapted from the gas Liberty since the CRD FSM WD's do not actually show the wiring as installed in the vehicle for the Fuel Priming Pump.

Fuse for pump is no. 17
Relay for pump is no. 38

turblediesel · **Posted:** Mon Jan 18, 2021 3:39 pm

Yup, relay #38 and #19 is where the wire was crudely stuffed with the relay plugged back in. I read #5 off the relay itself since I couldn't squint hard enough to read the numbers on the socket side.

My parts jeep is an '05.

jvecchione · **Joined:** Sat Jan 06, 2018 2:23 pm **Posts:** 33

I am in the process of doing this modification myself. Everything went pretty smoothly, but I wanted to save some money and only added two wires to the existing harness, but am getting no fuel coming from the outlet hose and I can hear the pump working. I have not installed the tank yet as I wanted to make sure everything was working and have about 1 liter of fuel in the tank. I am thinking I may have wired the pump with reverse polarity or maybe it takes a while to prime the pump. Not sure what to do

WWDiesel · **Posted:** Sat Sep 18, 2021 3:45 pm

jvecchione wrote:

I am in the process of doing this modification myself. Everything went pretty smoothly, but I wanted to save some money and only added two wires to the existing harness, but am getting no fuel coming from the outlet hose and I can hear the pump working. I have not installed the tank yet as I wanted to make sure everything was working and have about 1 liter of fuel in the tank. I am thinking I may have wired the pump with reverse polarity or maybe it takes a while to prime the pump. Not sure what to do

You probably wired it backwards and it is running in reverse.
Roll the wires and see if it starts to pumping. :wink:

Inline fuel pump in CRD -06 engine bay

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