AUXILLIARY LIFT PUMP CONSIDERATIONS

gmctd · **Posted:** Sun Apr 12, 2015 12:14 pm

Oh, it'll solve it, alright - in less time than it takes the glow plug lite to go out........................

dan86 · **Posted:** Sun Apr 12, 2015 12:46 pm

Good stuff. That's what I'm after! If it doesn't work, I'm coming after you!

2003 KJ Liberty 2.5 CRD

gmctd · **Posted:** Sun Apr 12, 2015 3:53 pm

No worries - if it doesn't work, you won't get very far :goink:

dan86 · **Posted:** Sun Apr 12, 2015 3:56 pm

On a serious note though- obviously air is getting in somewhere. I will be changing the plastic hoses off the tank for rubber ones and the outlet pipe from the filter head to pump will also be replaced. Obviously hope this will get rid of the air problem, but will fit a pump in the next few weeks to be absolutely sure. is there anywhere else air could be getting in? If so, will the pump be enough to overcome this and the starting issues?

2003 KJ Liberty 2.5 CRD

papaindigo · **Posted:** Sun Apr 12, 2015 4:02 pm

I know you have a different style fuel filter head than the one fitted in 05 and 06 but that said it is possible for air to get in at the filter head from such things as a loose filter, bad bleeder screw seat, failure of seal on primer pump, etc. You might try fitting a bit of clear vinyl tube to the inflow and outflow lines at the filter head which may allow you to see if the air is coming from the tank or the filter head.

WWDiesel · **Posted:** Sun Apr 12, 2015 4:10 pm

A properly installed in-tank lift pump will ensure absolutely no air can get into the fuel system period! Installing one outside the tank is the next best option provided you do as you stated and install leak proof hoses and clamps on the suction side of the lift pump. Either should solve any air in-leakage or infusion into the fuel system.... :wink:

gmctd · **Posted:** Sun Apr 12, 2015 5:23 pm

dan86 wrote:

On a serious note though- obviously air is getting in somewhere. I will be changing the plastic hoses off the tank for rubber ones and the outlet pipe from the filter head to pump will also be replaced. Obviously hope this will get rid of the air problem, but will fit a pump in the next few weeks to be absolutely sure. is there anywhere else air could be getting in? If so, will the pump be enough to overcome this and the starting issues?

2003 KJ Liberty 2.5 CRD

I wouldn't bother replacing either line unless it shows wet leak, altho you could replace the large one to tie into the external in-line lift pump
- the large line is fuel supply to the filter, would be the troublesome one
- smaller line is excess fuel return from the engine: any leak will be wet, but no complaints have been fielded, here

papaindigo · **Posted:** Mon Apr 13, 2015 8:32 am

I have to disagree a bit. A wet leak (easy to locate even small ones with a dry paper towel) indicates fuel leaking out but a dry joint is not an indication that no air is leaking in. In a pusher fuel system (in tank fuel pump) most any leaking is going to be wet. In a puller fuel system a leak may be wet (fuel getting out and maybe air getting in) or dry (air leaking in but no fuel escaping). My air leak was in the electric plug for the heater element in a 1s gen filter head and had no evidence of fuel escaping although if you crammed a "Q" tip into the female side of the plug on the head you could smell diesel on the "Q" tip.

As I understand it the fuel line from the tank to the filter head is "hard" (e.g. no quick disconnects) all the way to the filter head and unlikely to leak air anywhere but at the quick disconnects. Replacing the disconnects with quality fuel line is relatively easy and cheap and will fix fuel supply line air leaks if the disconnects are the source. If the air leak is bad enough you might see bubbles if you install a bit of clear vinyl tubing between the end of that line and the filter head (adding a "high" clear or clearish inline filter to the vinyl tube would help to see bubbles by capturing them in the "up" portion of that filter).

However as noted air can get in at the filter head and between the filter head and the CP3. Installation of an in line or in tank lift pump would make leaks at those places wet and less likely to let air into the system.

dan86 · **Posted:** Mon Apr 13, 2015 9:33 am

ok. quick update. this morning I changed the pipes as I said I would. I ended up doing the inlet and return on the fuel tank and from the head to cp3. I will use it as normal over the next few days and see how it goes. After I did it, I took it out for a quick drive. not sure how/why, but my mpg has gone up! only a tiny amount, but it's all good. I have stopped and started twice since doing it, and both times have been ok so far. will let it sit for a good few hours now and try again later on. Then it will sit overnight and try it again tomorrow. If it starts ok after sitting overnight, I'll call it a success. but will likely still fit a pump for good measure in the coming weeks. I plan on doing a picture heavy write up in the CRD Tech Only section later on if that's ok? I'm sure it will come in handy for somebody at some point.

2003 KJ Liberty 2.5 CRD

WWDiesel · **Posted:** Mon Apr 13, 2015 10:05 am

One more time!

Quote:

A properly installed in-tank lift pump will ensure absolutely no air can get into the fuel system period!

An in-tank lift pump puts the entire fuel system under a positive (+) pressure from where it first exits the fuel pump inside the fuel tank through all the fuel lines and fittings, through the fuel filter head, heater, and filter, all the way to the back of the CP3 injection pump. ANY LEAK anywhere on this system would show up as fuel leaking out. Air simply cannot get into the system while it is under 10-15 psig of pressure!!!
Simple laws of physics.... :wink:

My CRD had a small leak I discovered right after I installed the in-tank Carter lift pump last year. I kept smelling diesel fuel and upon investigation I found a very tiny leak on the filter head leaking just enough to make a wet spot on the back side of the filter keeping things wet. Repaired the fitting, cleaned and washed and leak and smell is gone! This fitting most likely was my air leak prior to installing the in-tank lift pump. I never would have found it had it not been for the addition of a lift pump!!!! :roll:

dan86 · **Posted:** Mon Apr 13, 2015 1:54 pm

Well a good 5 hours hrs has passed since I last switched off the engine. Went out, turned key, waited 12 seconds as I always do to make sure it gets a good heat, and hey presto. It started!
So far so good. It will now sit overnight and I'll try again tomorrow morning. hopefully my issues are behind me...

2003 KJ Liberty 2.5 CRD

WWDiesel · **Posted:** Mon Apr 13, 2015 2:14 pm

Bet you will be singing praises in the morning.... :rockon:

dan86 · **Posted:** Tue Apr 14, 2015 5:01 am

WWDiesel wrote:

Bet you will be singing praises in the morning.... :rockon:

well, it sat overnight. normally I would go and try and start it half an hour before I need to go anywhere just incase I needed to play around with it, but this morning I risked it and just went out to start it as I needed to leave. meaning, if it didn't, i'd have been late.
the result is- it started :BANANA:

It did take a split second longer than i'd have liked, but most definitely better.
lift pump is on the cards I think.

4wheeldeal · **Joined:** Thu Mar 15, 2012 11:11 pm **Posts:** 70

dan86 wrote:

Just been out to check. can't find anything relating to fuel pump

are there anymore fuses and relays anywhere I don't know about?

My jeep has this and the fuel pump priming fuse and reply. The fuel was blown oddly enough. Anyways there is no 12v when you turn the key on. Even when started no power. Odd how you guys are getting this to work using is and mine has it but has no power.

I'm looking for power that will turn on with the key yet power off after 20s etc. Guy on YouTube says to use the power under the seat, any truth to that?

Need this running tip top asap. Stalled at the exit to Napa picking up the pump.

Thanks

GordnadoCRD · **Posted:** Thu Aug 23, 2018 6:46 pm

Yes, the power connector under the rear left seat (and carpet, and padding) has correct wiring to it, and if your fuse and relay are good, should have correct power there, but the other end of that circuit is in the bottom of that power distribution box you have open.

4wheeldeal · **Joined:** Thu Mar 15, 2012 11:11 pm **Posts:** 70

Well got it working darn ground issues. Grounded to the battery bingo works. It's mounted in the engine compartment for now. This fixed my issue it will move out back by the tank. The bleeding doesn't seem to work so that's odd but it started.

AUXILLIARY LIFT PUMP CONSIDERATIONS

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