The New Fuel Filter, Filter Head, Lift Pump Thread

Anomious · **Posted:** Tue Jul 24, 2007 9:33 pm

Hi! I agree too! When I first read about the fuel heater problem, I put a dab of silicone grease in the connector. It will conduct heat away from the pins, help prevent corrosion, and keep any air from being drawn in. So far I have never had any evidence of air in the fuel,"so far"
I think that when one bleeds the filter it should be done with a short hose attached to the drain and It should be open while pumping. Pumping with it closed will pressurize the filter and cause it to leak. Remember! If you pump a container with 9 square inches of area to 20 lbs. of pressure you have put 180 lbs of push on it. Bleed with the valve open!

Sorry for the feral goose remark !

LK

Joe Romas · **Posted:** Tue Jul 24, 2007 10:25 pm

Anomious wrote:

I think that when one bleeds the filter it should be done with a short hose attached to the drain and It should be open while pumping. Pumping with it closed will pressurize the filter and cause it to leak. Remember! If you pump a container with 9 square inches of area to 20 lbs. of pressure you have put 180 lbs of push on it. Bleed with the valve open!
LK

That's how I bleed mine :lol:

It's been about a month since I did it and two days ago I had to push the plunger 20 time to get all the air out :shock:

It was really running crappy with the surging, bucking thing and now it's fine for a little while :cry:

Anomious · **Posted:** Tue Jul 24, 2007 11:44 pm

Try the silicone grease in your heater connector, it may help :idea:

LK

RFCRD · **Posted:** Wed Jul 25, 2007 5:52 am

Jeger wrote:

RFCRD wrote:

retmil46 wrote:

The other day, Ranger1 went for a trip when he was just above 1/4 tank, and stopped to fill up after 45 miles. He left the engine running, and before filling up hooked up to the fuel temp sensor to see what fuel temp was. The fuel being supplied from the tank registered 120 F at the filter! :shock:

Understand your concern about high fuel temps & vaporization but think your efforts may be self-defeating. Detroit Diesel's research in the '80's found hot diesel fuel temps (in the 120* F+ range) is where you will get the best combustion and fuel economy. This computer control package should be measuring fuel temp and adjusting injector pulse/timing to optimize efficiency or emissions. I believe that is a primary reason why mine wouldn't deliver over 24 mpg until the outside temps were in the 90's and would drop off sharply under 40*F. You may see these temps frequently in the South, but it's a mid-Summer only thing in Ohio. High temps may be causing some fuel vaporization but these temps are likely where the engineers want them to be for optimization.

Was their fuel under a vacuum though? I dont disagree that hot fuel may produce better combustion in a diesel, but I dont think gulping air is helping anything.

Perhaps a lift pump alone would be best? Get rid of that vacuum and raise the vaporization/boiling point higher than the temps we are seeing? An air trap that you could check at a glance would be nice....gotta finish that little project

Yes. The entire system was under vacuum. In the case of a bus it's pulling vacuum from a fuel tank that is 30 ft away from the engine. The key difference is the filters are mounted low on the fram rail (below the pump/injection hardware) where it doesn't trap air. This doesn't mean that it doesn't get air in the fuel, just doesn't have a place to form a pocket.

dgeist · **Posted:** Wed Jul 25, 2007 2:13 pm

tigafila wrote:

As promised here's the update on the Racor. Nothing to report!!!!! Not one stall, hesitation, no-start, nothing and it's been about 1000 miles. I'm actually driving it on a road trip right now (which is awesome because I never get to drive it) where I'll probably put on about another 1000 miles in the Apalachian and Blue Ridge mountains so that should be a good test. I'll stick my head in the lion's mouth again and say what a great driving vehicle (the last time I said that 5 minutes later the trans temp light came on and the torque converter failed). Tigafila

congrats.... no pics? :wink:

tigafila · **Posted:** Wed Jul 25, 2007 3:15 pm

No pics yet, I'm still on the road. I'll be home in 2 weeks, I'll post pics then. Tigafila

nursecosmo · **Posted:** Fri Jul 27, 2007 11:12 am

Has anyone yet discovered if the fuel primer pump circuit in the fuse box is active and if so are there any feed wires going to the rear of the vehicle?

MrMopar64 · **Posted:** Fri Jul 27, 2007 9:53 pm

Hello all, thought I'd shed some light on some questions.

*The Racor fuel head was used on 2004 and previous MY vehicles. The high pressure pump on those engines did not have the internal gear suction pump hence why they had a lift pump installed. The Racor unit was used because of the pressure supplied (approx 3 bar if memory serves correct). A similar unit was also used on the RG minivans.

*05+ KJ used the CP3 with internal suction pump. This did away with the lift pump as you've experienced. Filter is by UFI. Due to metering concept of pump, the gear suction pump is designed to deliver a certain volume flow into the pump. A lift pump will change this fuel delivery rate and will throw off the metering of the rail pressure, even if undetectable to the owner/operator. In conversion with some people at work, it was strongly advised against using the lift pump since a proper LPC shouldn't need it. There are vehicles at work with similar fuel systems that sit for weeks at a time and start <5 sec w/o priming.

*Fuel heater is indeed on all the time w/ the key. This sucks. I'd put it on a toggle switch so that it can be turned off. The ECU uses the fuel temp @ filter for high pressure pump protection. When fuel temps exceed 80-85degC then a derating of rail pressure/engine output will begin. The lift pump wiring in the fuse box shouldn't be present and if so won't be operational since the functionality is disabled in the cal and the control isn't in the wiring harness.

Cowcatcher · **Posted:** Fri Jul 27, 2007 10:05 pm

Thank you for your return and information Mr. Mopar.

You are a great resource. Do you know the source of the air in the system and the solution? Many think it is the puck and the heater. Is reporting the failed head to the Feds and pushing for a recall the only real solution?

retmil46 · **Posted:** Sat Jul 28, 2007 12:20 am

MrMopar64 wrote:

*Fuel heater is indeed on all the time w/ the key. This sucks.

Now THAT has to be the understatement of the century!

Tinman · **Joined:** Mon Apr 10, 2006 10:45 am **Posts:** 308

Well, if the fuel temp is only there for protection in case of high temps, then its not really needed. One could put in a fuel temp gauge then replace the sensor with a resistor that would get the CEL off. IF this is the only hold up on the Racor 245, then this would be easier than trying to figure out a way to use the sensor in a Racor filter head.

In light of what MrMopar said, it'd think we should think about the flow rate of these 2 micron filters. If the CP3 is very sensitive of low pressure supply to get correct rail pressure, then a small pressure drop thru a 2 micron filter may cause changes in rail pressure. I'm sure we can find flow rates of the Racor/Cat filters. But we need a stock filter flow to compair to.

MrMopar64 · **Posted:** Sat Jul 28, 2007 1:23 pm

Disconnecting the fuel temp sensor shouldn't set a check engine light. However, disconnecting the sensor will cause the ECU to default to a certain value which will cause it to be in a portion of the engine performance derating. The only time that we've ever experienced fuel cuts is while trailer towing at GCW up a very steep incline (7% grade, for example) with the fuel level just above the threshold for the low fuel light. I would personally leave the sensor connected so that if you do for some reason reach such a situation then you won't risk damage to the CP3 which no one wants...

I'll see if there are some flow numbers for the filter assembly that I can get.

jeep06 · **Posted:** Sat Jul 28, 2007 2:08 pm

I think the real problem here is "Where is the air being sucked into the system"? It seems every CRD Liberty owner on here all have the same problem, we just need some way to cure it with out voiding our warranty. Good work and thanks for the info!!!!

retmil46 · **Posted:** Sat Jul 28, 2007 5:08 pm

Let's see. 80 to 85 C is 176 to 185 F. You said you've experienced at least one instance of fuel/engine cutback due to this. For that matter, myself and several other people have experienced similar reductions in power. Either the reduction in fueling/power actually begins at a lower temp and is only really noticeable once it hits 80 to 85 C, or the conditions where fuel temp can reach these levels is not as rare as you believe.

The problems haven't been when starting cold initially. For my part, it has been in stop and go operation - restarting after it's been driven enough to be fully warmed up, then shut down for a period of time where apparently the fuel filter has time to heat soak next to the engine. Also on a long interstate trip during warm weather - after driving for 2 hours or more, then a 20 minute rest stop, then restarting to get back on the interstate. I've noticed a definite reduction in power and performance under these conditions, and prolonged cranking (twice the normal interval) required to restart the engine. Others have mentioned similar symptoms, particularly out west with the recent high ambient temps, up to and including stalling.

The fuel filter and the temp sensor are the first components the fuel goes thru after leaving the tank, other than approx 10 ft of fuel line. For the fuel to be at 80 to 85 C when it hits the fuel sensor, that means the fuel tank is approximately at the same temp, or another possibility I mentioned above, the filter has had a prolonged thermal soak sitting next to a hot engine.

Over on the tdi forums, word is that the '08 common rail VW diesels will be pumping upwards of 30,000 psi, and that pumping fuel up to these pressures will heat it up in excess of 200 F. Therefore, VW has said that you won't be able to use any form of biodiesel, as it will break down at these temps and end up gumming up injectors and such. Wonder what those beasts will see for fuel temps with 200 F fuel getting recirced to the tank.

To me, the easiest and most certain method of protecting that $3K injection pump is to make sure the fuel temp never gets to those levels on the supply side. Given everything I've seen on this beast over the past 2 years, instead of relying solely on a 25 cent thermistor and DC's software in the ECM, I'll put my faith in good old-fashioned heat transfer and fluid flow - insulation on the fuel filter and supply lines, and a fuel cooler in the return line.

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

retmil46 wrote:

Let's see. 80 to 85 C is 176 to 185 F. You said you've experienced at least one instance of fuel/engine cutback due to this. For that matter, myself and several other people have experienced similar reductions in power. Either the reduction in fueling/power actually begins at a lower temp and is only really noticeable once it hits 80 to 85 C, or the conditions where fuel temp can reach these levels is not as rare as you believe.

The problems haven't been when starting cold initially. For my part, it has been in stop and go operation - restarting after it's been driven enough to be fully warmed up, then shut down for a period of time where apparently the fuel filter has time to heat soak next to the engine. Also on a long interstate trip during warm weather - after driving for 2 hours or more, then a 20 minute rest stop, then restarting to get back on the interstate. I've noticed a definite reduction in power and performance under these conditions, and prolonged cranking (twice the normal interval) required to restart the engine. Others have mentioned similar symptoms, particularly out west with the recent high ambient temps, up to and including stalling.

Ditto what he said. It gets above 110 here routinely. Sometimes the thing became gutless-- under the circumstances described above, Filling the tank usually cured it or drastically improved it. This summer I unplugged the heater and life is much better.

tigafila · **Posted:** Sat Jul 28, 2007 11:50 pm

The fuel temp sensor does turn the CEL on if disconnected. Tigafila

cumminspilot · **Posted:** Sun Jul 29, 2007 2:30 am

unhooking fuel temp sensor reduces power --confirmed

actually pulling the temp sensor out while wondering why the plug is so tight --is a good reason to replace a leaking housing

BBB · **Posted:** Sun Jul 29, 2007 9:49 am

Is there simple a fuse/connector one could pull out to just imobilize the filter fuel heater alone (for summer months) or would that fuse/connector also power the sensor and others and cause a CEL? If the heater leads could be isolated, a simple bi-metal inline thermostat could be installed to let the heater be powered on below a specific user adjustable tempurature set point for winter months. Is the computer is looking for the heater resistance 100% of the time? If so what is the resistance so a resistor could be wired series-parrallel with the new themostat?

BiodieselJeep.com · **Posted:** Sun Jul 29, 2007 11:13 am

Mother Fu@%rs! My pregnant wife drives this vehicle with my 2 year old son. Been having trouble (stall after start-up, Electronic Thottle Control light flashing). Pulled the heater plug and actually heard air sucking into the hole! I'm gonna make somebody BLEED for this:

I need to plug that hole today before I bring it in to the stealer. Any caulk suggestions?

I am so angry! This is a HUGE hazard, can't imagine the consequences. To quote a favorite old song: If I had a rocket launcher, some son-of-a-b!+@h would die.

Cowcatcher · **Posted:** Sun Jul 29, 2007 11:54 am

Well obviously it is burned out since the pin is stuck in the plug so the whole head will need to be replaced since the puck isn't available by itself so anything you do to it to make it driveable won't hurt it. I think I would just fill it with silicone and make sure it has time to dry before you drive it.

You do need to report it to the feds!!!

The New Fuel Filter, Filter Head, Lift Pump Thread

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