Air in fuel

click23 · **Joined:** Thu May 11, 2006 9:22 am **Posts:** 309

With in 2 months I plan on purchasing a CRD so I have been reading up issues you guess are having and came across this over at PM:

6. RE: Our Long-Term Jeep Liberty CRD (Diesel)
I have had the 2006 CRD for just over a year now with 62,000 miles, 80% of that highway. I have had only one problem with it, the fuel filter washer was letting air get sucked into the fuel lines by the high pressure pump which caused erratic idle, shaking and stalling. The tech figured it out after a few hours and replaced the washer. No problems since. I get, regularly, 28 mpg highway (driving 65-70). I see a lot of mixed experiences with the CRD, but mine has been very good. I have found the odometer to be off by more than 5 miles for every 100, and the speedometer is 3 mph off, I switched to 245/75R-16 and it's near spot on. I think they can adjust that through the program as well, but I needed an excuse to put on the extra rubber anyway.

(full article: http://tinyurl.com/2oo6a4)

I have seen where some people have thought that the problem was with the fuel filter, but not replacing the washer could fix the problem.

Robert

dgeist · **Posted:** Wed Aug 01, 2007 5:19 pm

click23 wrote:

With in 2 months I plan on purchasing a CRD so I have been reading up issues you guess are having and came across this over at PM:

(full article: http://tinyurl.com/2oo6a4)

I have seen where some people have thought that the problem was with the fuel filter, but not replacing the washer could fix the problem.

Robert

I think you'll find that for each person with an air leak problem, there's a unique source of the air (or it seems like that). That tester was lucky it was only the filter seal. Mine has been good for a couple months, now, after rebuilding the head twice, putting silicone grease on all the fittings, dielectric on the sensor plugs, and swapping out a thicker gasket for the seal between the "puck" and head (and one good "rev the engine like you're stealing it" cycle.

CATCRD · **Posted:** Wed Aug 01, 2007 6:53 pm

dgeist wrote:

I think you'll find that for each person with an air leak problem, there's a unique source of the air (or it seems like that). That tester was lucky it was only the filter seal. Mine has been good for a couple months, now, after rebuilding the head twice, putting silicone grease on all the fittings, dielectric on the sensor plugs, and swapping out a thicker gasket for the seal between the "puck" and head (and one good "rev the engine like you're stealing it" cycle.

Where did you get something for the seal between the puck and the head? I think that's the source of my leaks.

BankNote4X4 · **Posted:** Wed Aug 01, 2007 6:58 pm

Where did you get something for the seal between the puck and the head? I think that's the source of my leaks.[/quote]

The rubber seal from the factory fuel filter can be swapped for the current one to improve the seal(its taller).

jeep06 · **Posted:** Thu Aug 02, 2007 12:21 am

So how new of a filter head do you have to get and it will be the new improved (taller) washer? I had my filter assembly changed under warranty a few months ago because it has always seeped fuel between the heater puck and the mounting base, but it still sucks air/seeps fuel. I could bleed it every day I think and get air out of the system, just poor design on DCX's part once again. Oh well, the bad part is I can't even trade it on a Wrangler since their resale is just about as good as the fuel system...haha.

Endurance · **Posted:** Thu Aug 02, 2007 12:33 am

this air in fuel BS is driving me insane. If I dont bleed my system every 2 days my average mileage goes down by 1mpg. Any fix on this yet?

Joe Romas · **Posted:** Thu Aug 02, 2007 7:38 am

jeep06 wrote:

Oh well, the bad part is I can't even trade it on a Wrangler since their resale is just about as good as the fuel system...haha.

Not exactly so

There were only 11,000 or so made for the US market and there will always be a demand for them :shock:

What you have are dealers wanting to buy it cheap from you and sell it high to interested buyers :wink:

I have experienced this for many years at VW dealers

At trade in time, "nobody wants a diesel" then when your looking to buy used it's "they're hard to find and we have a waiting list for them"

Take what they tell you with a grain of salt. :!:

You take a bath when trading in any car that's just a few years old

dgeist · **Posted:** Thu Aug 02, 2007 8:44 am

jeep06 wrote:

So how new of a filter head do you have to get and it will be the new improved (taller) washer? I had my filter assembly changed under warranty a few months ago because it has always seeped fuel between the heater puck and the mounting base, but it still sucks air/seeps fuel. I could bleed it every day I think and get air out of the system, just poor design on DCX's part once again. Oh well, the bad part is I can't even trade it on a Wrangler since their resale is just about as good as the fuel system...haha.

The filter gasket and the "puck" gasket (between the sensor section and the aluminum head) are the same diameter and intentation pattern. The filter gasket is about twice the thickness, though. After you change the fuel filter (and in my case after I switched it with the Cat2 mod) you can rebuild the head/puck assembly by unscrewing the center pipe thingy inside (which usually requires using a vice for a good grip since there's threadlock on it).

Dan

retmil46 · **Posted:** Thu Aug 02, 2007 8:48 am

Endurance wrote:

this air in fuel BS is driving me insane. If I dont bleed my system every 2 days my average mileage goes down by 1mpg. Any fix on this yet?

So far, regardless of what Mopar64 has been told by his colleagues, a 4 psi centrifugal lift pump has worked wonders on mine. Not a bit of air.

As far as the CP3 pump calibration being affected by a lift pump - one individual has hooked up test equipment and monitored rail pressure under various driving conditions, both with and without a lift pump. No change whatsoever, fuel rail pressures were unaffected. Only noticeable differences were engine ran much quieter, throttle response was improved, and no problems with air buildup in the filter.

Same individual also tracked down the Bosch literature which states that our particular CP3 pump will work with up to 16 psi on the inlet, that you would encounter problems only when you exceeded 16 psi.

jeep06 · **Posted:** Thu Aug 02, 2007 8:53 am

Joe Romas wrote:

jeep06 wrote:

Oh well, the bad part is I can't even trade it on a Wrangler since their resale is just about as good as the fuel system...haha.

Not exactly so

There were only 11,000 or so made for the US market and there will always be a demand for them :shock:

What you have are dealers wanting to buy it cheap from you and sell it high to interested buyers :wink:

I have experienced this for many years at VW dealers

At trade in time, "nobody wants a diesel" then when your looking to buy used it's "they're hard to find and we have a waiting list for them"

Take what they tell you with a grain of salt. :!:

You take a bath when trading in any car that's just a few years old

Yes I agree on all of the above. From what I have been told, the black book price on mine with 16k miles, is around $16k-$16.5k. So if you go by the dealers black book price which is about $4k below KBB and NADA trade in values, it isn't worth trading it in. I have seen several listed for sale at dealers ranging from $24,900 all the way up to $27,900 which is pretty much new price if you got a good deal at the time. Guess if and when I am ready to get rid of mine, I will have to sell it out right to get any fair money for it at all. If they could get this air in the fuel problem somewhat fixed, I might consider keeping it a little longer, but bleeding it on a regular basis is getting under me skin. Maybe if one of us comes up with a 100% fix, we can sell the idea to DCX for huge $$$$$$$$$ NOT...haha.

:)

jeep06 · **Posted:** Thu Aug 02, 2007 9:00 am

retmil46 wrote:

Endurance wrote:

this air in fuel BS is driving me insane. If I dont bleed my system every 2 days my average mileage goes down by 1mpg. Any fix on this yet?

So far, regardless of what Mopar64 has been told by his colleagues, a 4 psi centrifugal lift pump has worked wonders on mine. Not a bit of air.

As far as the CP3 pump calibration being affected by a lift pump - one individual has hooked up test equipment and monitored rail pressure under various driving conditions, both with and without a lift pump. No change whatsoever, fuel rail pressures were unaffected. Only noticeable differences were engine ran much quieter, throttle response was improved, and no problems with air buildup in the filter.

Same individual also tracked down the Bosch literature which states that our particular CP3 pump will work with up to 16 psi on the inlet, that you would encounter problems only when you exceeded 16 psi.

This sounds so much like the '98.5 Dodge/Cummins saga I went through with the VP44 injection pump woes. Not enough pressure/volume, you toast the pump @$1600. Too much pressure and you ruin it also. The lift pump sounds like a great idea, I was shocked they didn't have any kind of external pump from the factory...but they have to keep the bean counters happy.

cumminspilot · **Posted:** Fri Aug 03, 2007 12:27 am

So far, regardless of what Mopar64 has been told by his colleagues, a 4 psi centrifugal lift pump has worked wonders on mine. Not a bit of air.

As far as the CP3 pump calibration being affected by a lift pump - one individual has hooked up test equipment and monitored rail pressure under various driving conditions, both with and without a lift pump. No change whatsoever, fuel rail pressures were unaffected. Only noticeable differences were engine ran much quieter, throttle response was improved, and no problems with air buildup in the filter.

Same individual also tracked down the Bosch literature which states that our particular CP3 pump will work with up to 16 psi on the inlet, that you would encounter problems only when you exceeded 16 psi.[/quote]

where did you mount your pump and whose pump did you use oh and did you take pictures

jeep06 · **Posted:** Fri Aug 03, 2007 1:36 am

The filter gasket and the "puck" gasket (between the sensor section and the aluminum head) are the same diameter and intentation pattern. The filter gasket is about twice the thickness, though. After you change the fuel filter (and in my case after I switched it with the Cat2 mod) you can rebuild the head/puck assembly by unscrewing the center pipe thingy inside (which usually requires using a vice for a good grip since there's threadlock on it).

Dan[/quote]

So Dan all you do is pull the old fuel filter and remove the gasket from that and put it in place of the OEM heater puck gasket and all is good? I can see where that would help, even on this new head that the dealer installed it is seeping just like the original. I never over pump the primer either knowing it would no doubt blow the fuel through the fuel heater connector port, I use the side of my index finger to pump the primer and when I start to feel slight pressure, I open the bleeder valve. It would make life so much better to get this air problem fixed,,,shoot I might even keep it awhile then...haha. Thanks for the info!! Everyone keep up the good work.

BankNote4X4 · **Posted:** Fri Aug 03, 2007 10:00 am

cumminspilot wrote:

So far, regardless of what Mopar64 has been told by his colleagues, a 4 psi centrifugal lift pump has worked wonders on mine. Not a bit of air.

As far as the CP3 pump calibration being affected by a lift pump - one individual has hooked up test equipment and monitored rail pressure under various driving conditions, both with and without a lift pump. No change whatsoever, fuel rail pressures were unaffected. Only noticeable differences were engine ran much quieter, throttle response was improved, and no problems with air buildup in the filter.

Same individual also tracked down the Bosch literature which states that our particular CP3 pump will work with up to 16 psi on the inlet, that you would encounter problems only when you exceeded 16 psi.

1. where did you mount your pump and whose pump did you use oh and did you take pictures[/quote]
2. Are there any issues that can be foreseen with this lift pump hurting the internal pump?
3. What is Mopar64 using for information to say we can't do the lift pump????????
4. RETMIL: Are you running the cooler back into the tank? Are you still using the insulation?
Do you still believe its gas being broken out, and the lift pump reduces that.

Sounds like we may have a solution

:):):)

Am I ready for 300,000 miles yet?

ATXKJ · **Posted:** Fri Aug 03, 2007 10:08 am

MrMopar was running his on a dyno and had problems even at low pressure (I think 1psi) - however it appears there are more variables at play in the vehicle which responds well to a lift pump - vs the dyno room which had problems.

dgeist · **Posted:** Fri Aug 03, 2007 5:53 pm

jeep06 wrote:

So Dan all you do is pull the old fuel filter and remove the gasket from that and put it in place of the OEM heater puck gasket and all is good? I can see where that would help, even on this new head that the dealer installed it is seeping just like the original. I never over pump the primer either knowing it would no doubt blow the fuel through the fuel heater connector port, I use the side of my index finger to pump the primer and when I start to feel slight pressure, I open the bleeder valve. It would make life so much better to get this air problem fixed,,,shoot I might even keep it awhile then...haha. Thanks for the info!! Everyone keep up the good work.

For me, yes... but you have to remember that the reason mine was leaking in the first place was that I did the Cat 2-micron filter swap which replaces the center spindle (I think once you break the seal on the puck, it's a bugger to get it sealed well again). I wouldn't go taking things apart unless you KNOW that's where the leak is, since you might be making the problem potentially worse. The bad part is that it's near impossible to figure out where the leak is, exactly.... which is why I can't wait to convert mine the next time it starts getting finicky.

Larry R. · **Joined:** Sun Jan 21, 2007 1:35 am **Posts:** 92

Hey retmil46, I was wondering were you got the info on the lift pump pressure spec of 16 psi or less is permissable, I am curious if there is any more usefull info there?

CATCRD · **Posted:** Sun Aug 05, 2007 3:27 pm

I already tossed the stock fuel filter when I converted to the Cat one. Short of buying a new filter, does anyone know the measurements of the seal in question between the heater puck and the mounting head? I bet I could find something if I knew a rough size to look for, thickness, etc.

techTim · **Posted:** Sun Aug 05, 2007 4:19 pm

retmil46 wrote:

Endurance wrote:

this air in fuel BS is driving me insane. If I dont bleed my system every 2 days my average mileage goes down by 1mpg. Any fix on this yet?

So far, regardless of what Mopar64 has been told by his colleagues, a 4 psi centrifugal lift pump has worked wonders on mine. Not a bit of air.

As far as the CP3 pump calibration being affected by a lift pump - one individual has hooked up test equipment and monitored rail pressure under various driving conditions, both with and without a lift pump. No change whatsoever, fuel rail pressures were unaffected. Only noticeable differences were engine ran much quieter, throttle response was improved, and no problems with air buildup in the filter.

Same individual also tracked down the Bosch literature which states that our particular CP3 pump will work with up to 16 psi on the inlet, that you would encounter problems only when you exceeded 16 psi.

MRMopar64, Retmil46;
lets see the supporting documentation please, this vacuum system sucks, pardon the pun.

CATCRD · **Posted:** Sun Aug 05, 2007 7:39 pm

CATCRD wrote:

I already tossed the stock fuel filter when I converted to the Cat one. Short of buying a new filter, does anyone know the measurements of the seal in question between the heater puck and the mounting head? I bet I could find something if I knew a rough size to look for, thickness, etc.

Would the seal off a 1R0750 work? It's probably 1/4" thick though.

Air in fuel

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