2006 Air in fuel line issues - knowledge base questions

racertracer · **Posted:** Sat Jun 01, 2019 9:44 pm

Hello, CRD owners and enthusiasts, I have encountered a problem with air in the fuel line leading from the tank to the heated fuel head. to eliminate the possibility of air coming in from the fuel line connectors closest to the fuel tank without dropping the tank, I cut away the connectors and spliced in in rubber fuel hoses in their places with screw clamps, tight and I am still getting air in.

1. Will an in tank fuel pump eliminate the problem?
2. Has anyone encountered the cause of the problem to be the connectors at the top of the tank?

Any ideas?

WWDiesel · **Posted:** Sat Jun 01, 2019 10:19 pm

An intank pump will eliminate ALL air in fuel problems or possibilities as it puts the entire fuel system from inside the fuel tank all the way to the back of the CP3 fuel injection pump under positive pressure so no air can be sucked in or ingested into the fuel.
And the beauty of it is, if you have a leak anywhere on your fuel system from the tank to the back of the CP3 injection pump, it will become self evident very quickly when you power up the the intank fuel pump as fuel will leak OUT instead of air leaking in, so you will be able to find a leak or leaks very easily.
Next to EGR removal, installing an intank fuel pump is one of the very best mods you can do to your Jeep CRD to prevent long term running issues... :BANANA:

racertracer · **Posted:** Sat Jun 01, 2019 10:22 pm

WW .. thank you

TKB4 · **Posted:** Sun Jun 02, 2019 1:39 am

The source could well be the fuel filter head itself. I had one that started leaking from the air bleed valve even when it was very securely tightened. You could remove the splice you made at the tank and fill a baster or big syringe with fuel and put end in the hose and supply some pressure and see if it leaks. You would be acting as an in tank pump.

racertracer · **Posted:** Sun Jun 02, 2019 3:15 am

TKB4 wrote:

The source could well be the fuel filter head itself. I had one that started leaking from the air bleed valve even when it was very securely tightened. You could remove the splice you made at the tank and fill a baster or big syringe with fuel and put the end in the hose and supply some pressure and see if it leaks. You would be acting as an in tank pump.

I just installed an inline lift pump near the fuel head to see if it would help and it didn't help, I can hear gurgling and air being sucked in from inside the tank somewhere.

flash7210 · **Posted:** Sun Jun 02, 2019 8:33 am

racertracer wrote:

TKB4 wrote:

The source could well be the fuel filter head itself. I had one that started leaking from the air bleed valve even when it was very securely tightened. You could remove the splice you made at the tank and fill a baster or big syringe with fuel and put the end in the hose and supply some pressure and see if it leaks. You would be acting as an in tank pump.

I just installed an inline lift pump near the fuel head to see if it would help and it didn't help, I can hear gurgling and air being sucked in from inside the tank somewhere.

Do you have fuel in the tank?
Maybe the fuel pickup is broken inside the tank.

Other possible points:
Where the hard plastic line connects to the top of the tank.
Where the hard plastic line connects to the metal line above the rear axle.
Where the metal line is crimped to the rubber line next to the fuel filter.

racertracer · **Posted:** Sun Jun 02, 2019 10:57 am

flash7210 wrote:

Do you have fuel in the tank?
Maybe the fuel pickup is broken inside the tank.

Other possible points:
Where the hard plastic line connects to the top of the tank.
Where the hard plastic line connects to the metal line above the rear axle.
Where the metal line is crimped to the rubber line next to the fuel filter.

1. Do you have fuel in the tank? YES
2. Maybe the fuel pickup is broken inside the tank.
3. Where the hard plastic line connects to the top of the tank.
4. Where the hard plastic line connects to the metal line above the rear axle.
5. Where the metal line is crimped to the rubber line next to the fuel filter.

I will be checking all of the above soon. I ordered the in-tank pump and will be getting things ready for a soon to occur weekend project. I'll report back.

WWDiesel · **Posted:** Sun Jun 02, 2019 12:22 pm

racertracer wrote:

I just installed an inline lift pump near the fuel head to see if it would help and it didn't help, I can hear gurgling and air being sucked in from inside the tank somewhere.

More than likely the flexible suction pipe has cracked inside the tank on the OEM fuel gauge/fuel pickup module.
You will know for sure when you remove the OEM module to replace it with a new module that has the fuel pump in it.

Picture of Carter fuel tank module with fuel pump:
Notice the flexible fuel lines.

racertracer · **Posted:** Sun Jun 02, 2019 5:20 pm

WWDiesel wrote:

[
Picture of Carter fuel tank module with fuel pump:
Notice the flexible fuel lines.

yes, i understand.

TKB4 · **Posted:** Sun Jun 02, 2019 5:34 pm

Racetracer, I know you have had way too much experience working on your CRD s especially one. I also know if you are going to drop the fuel tank you don't want to fill it up. I am curious as to about how much fuel you have in the tank now when the air in fuel started. . I see the pic from WW ( BTW Camo is my favorite color WW) but I wasn't aware the pickup was basically the same setup as the pump used as the pickup but without the pump.

racertracer · **Posted:** Sun Jun 02, 2019 6:00 pm

TKB4 wrote:

Racetracer, I know you have had way too much experience working on your CRD s especially one. I also know if you are going to drop the fuel tank you don't want to fill it up. I am curious as to about how much fuel you have in the tank now when the air in fuel started. . I see the pic from WW ( BTW Camo is my favorite color WW) but I wasn't aware the pickup was basically the same setup as the pump used as the pickup but without the pump.

TKB4 ... approximately 1/2 a tank.

racertracer · **Posted:** Mon Jun 03, 2019 2:45 am

Pardon, I failed to respond to the other question.

I began to notice a gradual decrease in pedal responsiveness about a month ago and then it totally stopped running a few weeks ago.

WWDiesel · **Posted:** Mon Jun 03, 2019 11:47 am

racertracer wrote:

Pardon, I failed to respond to the other question.
I began to notice a gradual decrease in pedal responsiveness about a month ago and then it totally stopped running a few weeks ago.

It will very interesting as to what you find when you drop and open up the fuel tank... :POPCORN:

racertracer · **Posted:** Tue Jun 11, 2019 4:12 am

Update, the air was coming in from a deteriorated hose. I replaced all the fuel hoses and fixed the problem. the air wasn't coming in from inside the tank. Not sure why air gurgling in the tank.

GordnadoCRD · **Posted:** Tue Jun 11, 2019 6:56 am

racertracer wrote:

Update, the air was coming in from a deteriorated hose. I replaced all the fuel hoses and fixed the problem. the air wasn't coming in from inside the tank. Not sure why air gurgling in the tank.

If air is entering the system, the first place the CP3 will try to deal with it is the cascade overflow valve, which returns as much as possible through the cp3 return fuel line.
Air exceeding it's ability to cope will go through the rail, causing air compressability problems, and be returned to the tank via the Fuel Pressure Solenoid at the back.
Either way, it all gets returned to the tank. This could have been what you heard?

TKB4 · **Posted:** Tue Jun 11, 2019 7:53 am

Thanks for update. I am glad to hear that you got your problem fixed. I am also glad to hear that it was not broken pickup in the tank since that might mean it was more vulnerable for others in the future, even for those with an in-tank pump.

On a somewhat related note. I haven't actually looked at the plastic fitting above the tank but at least for that type fitting I wonder if it would be possible to wrap the fitting with something like a special tape or "paint" it with a particular epoxy . It seems that especially without a lift pump or with a non in tank pump that the suction rather than pressure would aid in the sealing if they could be fixed in this manner. Racetracer essentially did this by clamping the fuel line over the fittings.

Is it possible to even reach to touch the plastic fitting above the tank without lowering the tank ?

I remember in the past there was some discussion of even replacing the pump by cutting an access panel in the rear floor perhaps if only a small hole was needed to fix the fitting the problems could be alleviated with less time and trouble . I am well aware that many would not want to make a hole in the floor but I still wonder about this even to replace the pump. Since I haven't lowered my tank I don't really have much insight regarding this.

WWDiesel · **Posted:** Tue Jun 11, 2019 1:21 pm

Cutting a hole in the floorboard to me seems a little extreme, but to each his own, it's their vehicle. I personally would never do that. :ALONE:

It is not a hard job to drop the fuel tank provided you run the vehicle until the tank is almost empty if possible.
Only requires disconnecting the tank filler pipe and two support straps.
Then drop the tank down, disconnect the hoses and unplug the wiring connector on top of the tank and then slide it out to fully drain the tank and R&R the fuel tank module.
While you got it out, inspect the inside of the tank real good for cleanliness.
Install is reverse. Having a floor jack to lower and raise/support the fuel tank can also be a big help.

flash7210 · **Posted:** Tue Jun 11, 2019 1:56 pm

Facet 40109

Not as good as the in tank pump.
But mine has been working great for about 10 years now.

WWDiesel · **Posted:** Tue Jun 11, 2019 11:55 pm

flash7210 wrote:

Facet 40109

Not as good as the in tank pump.
But mine has been working great for about 10 years now.

and certainly still beats NO pump! :rockon:

My Dodge Cummings is still running the external Carter OEM lift pump that is mounted to the side of engine block.
The only replacement for it now is a Mopar intank unit and wiring harness kit. ~$500.00+ Ouch! :banghead:

A Facet or equivalent type may be in it's future... :ROTFL:

gollygeemister · **Posted:** Wed Jun 12, 2019 10:44 pm

flash7210 wrote:

Facet 40109

Not as good as the in tank pump.
But mine has been working great for about 10 years now.

About the same here. My first 40109 lasted 7 or 8 years, and the new one has been on for 3 or 4 now. What I like is that if it dies I can bypass it with a screwdriver in 5 minutes. When your in-tank pump fails, you are DRT :dead:

It happened to someone here a while back.

2006 Air in fuel line issues - knowledge base questions

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