Weird CRD problem ??...

Liberty02sport · **Posted:** Fri Jun 14, 2019 5:56 pm

Have an '06 CRD that we've had for about a year now and I'm having a problem I just can't figure out. Jeep has 189K on it and the motor sounds good. Just replaced the timing belt, water pump, timing idler pulleys,etc. with the timing belt kit from IDparts, also has the Weeks stage 1&2 kit for EGR delete. Also the fuel filter was recently replaced in Feb. Oil used is shell Rotella T6 for the diesel.

OK, now onto the problem...Coming home from a shopping run I noticed the Jeep didn't seem to be responding to throttle input from the pedal...Step on the gas pedal, all the way to the floor, and the engine S-L-O-W-L-Y starts to climb the tach. & it doesn't seem to pick up any speed. It's like it has no turbo or passing gear and this is with the pedal buried to the floor. It just turns into a absolute dog on throttle response with no power ???...I was driving down the highway and had let off the throttle as I was going downhill, as the road leveled out I stepped on the throttle and it just seemed to ignore the input. The engine very slowly started to go from about 1600rpm to 2500rpm with the pedal pressed to the floor. When I stopped to turn onto my road it accelerated smoothly to about 30mph and despite burying the pedal again it would only sluggishly respond and wouldn't increase speed. The motor doesn't race, it just slowly starts to increase it's RPM with little to no increase in vehicle speed. You put it in park and give it throttle & motor responds quickly as it should, only seems to exhibit the slow throttle response problem under load

It did this one time before but after looking around under the hood I found a sensor that had I must not have gotten plugged all the way back in after swapping out the airbox for the gasser model airbox. It wasn't the MASS sensor, it was the other one on the side of the airbox lid, that was unplugged. So after plugging it back in & driving the Jeep the next day it all seemed fine again...

Today when it did it on the way home I again checked the sensor plug and it was tight so I'm guessing it wasn't the original issue after all. After getting in the driveway I put it in park and blipped the throttle a few times to check throttle response and the engine responded by quickly climbing the tach as would be expected. It revved smoothly & cleanly each time I pressed the pedal.

Not sure if the engine isn't getting the fuel to it fast enough (no lift pump installed) to rev when under load, or if it's having trans. issues, or a MAP sensor problem feeding the PCM bad info. or what is going on.....Anyone else run into this ?? I tried the search function and couldn't come up with anything that fit the problem. Thanks.

flash7210 · **Posted:** Fri Jun 14, 2019 6:36 pm

Sure sounds like limp mode.
You need to scan for codes.

Liberty02sport · **Posted:** Fri Jun 14, 2019 8:44 pm

flash7210 wrote:

Sure sounds like limp mode.
You need to scan for codes.

Had a buddy who runs his own shop doing a lot of diesel work run the codes the first time it did this and came up with only the EGR codes due to the Weeks kits install. When road tested with him in the passenger seat monitoring it it ran fine with no issues...Got on the throttle and it responded as it should, went into passing gear and took off down the road like the devil was chasing it. Buddy thought I was nuts for bringing it in since it behaved normally.

This is what has me so flummoxed...it's not easily repeatable. When searching it seems this can be caused by anything from the Mercedes sensor being unplugged to turbo gone out to TCM issues ??? Really driving me batty trying to get a handle on this.

Just went out to bleed the filter head...After pumping it up it started leaking fuel around one of the electrical connectors. Could this be the problem ??

flash7210 · **Posted:** Fri Jun 14, 2019 9:50 pm

Yup.
Leaking fuel filter head will definitely do that.
A well known problem identified at least 10 years ago.
Get a new fuel filter assembly with wiring.
You should also consider installing a lift pump.

Liberty02sport · **Posted:** Fri Jun 14, 2019 10:22 pm

flash7210 wrote:

Yup.
Leaking fuel filter head will definitely do that.
A well known problem identified at least 10 years ago.
Get a new fuel filter assembly with wiring.
You should also consider installing a lift pump.

Thanks. It'll be the first thing I do Monday. The ones sold by NAPA do OK or should I look at a particular brand ?? Reason I ask is that some of NAPA parts line touts itself as "product improved" and my buddy uses NAPA parts at his shop exclusively and has very few returns for bad parts.

flash7210 · **Posted:** Fri Jun 14, 2019 10:29 pm

You’ll need a new filter head and wiring kit.
AFAIK, the mopar part is the only replacement.
It will come with a new filter.
https://www.idparts.com/updated-fuel-filter-head-liberty-crd-p-4723.html

Billua · **Joined:** Sat Nov 25, 2006 5:05 pm **Posts:** 64

If it was a dog with no black smoke, most likely fuel related. If Black smoke and no boost, turbo or vacuum line to actuator issue...

Lift pump recommended is the Carter in tank pump..

Liberty02sport · **Posted:** Sat Jun 15, 2019 2:31 pm

Well, just pulled the fuel heater connector from the filter head assembly. Sure enough half the connector is burnt as well as the corresponding socket on the filter head. Anyone have a link to the lift pump by chance ?? Thanks.

WWDiesel · **Posted:** Sat Jun 15, 2019 10:30 pm

Liberty02sport wrote:

Well, just pulled the fuel heater connector from the filter head assembly. Sure enough half the connector is burnt as well as the corresponding socket on the filter head. Anyone have a link to the lift pump by chance ?? Thanks.

Airtex E7181M or CARTER P76148M :google:

Plenty of them out there!

https://www.amazon.com/Carter-P76148M-F ... B001UCASNQ
https://shop.sasquatchparts.com/product ... 5143160aa/
https://shop.sasquatchparts.com/product ... berty-crd/

turblediesel · **Posted:** Sun Jun 16, 2019 6:14 pm

New filter head should be metal. Wiring is slightly different. ID Parts has a kit.

geordi · **Posted:** Sun Jun 16, 2019 8:44 pm

Temp fix in the meantime - Spray out that socket with brake cleaner, dry it, and fill it with any RTV you have laying around. This will form a solid plug that will block the air leak. When you get the new filter head, don't bother plugging in the fuel heater. It is NOT needed and the computer won't know anything is missing.

stp2136 · **Joined:** Sat Sep 29, 2007 8:30 am **Posts:** 35

Fuel heater in the filter head may not be needed in the summer but it is a good idea to have it functioning in the winter in case you have a tank of straight # 2 (non winterized) diesel and the ambient temp gets below + 20 degrees F where # 2 starts to wax up.

geordi · **Posted:** Mon Jun 17, 2019 2:50 pm

stp2136 wrote:

Fuel heater in the filter head may not be needed in the summer but it is a good idea to have it functioning in the winter in case you have a tank of straight # 2 (non winterized) diesel and the ambient temp gets below + 20 degrees F where # 2 starts to wax up.

You'd think so... But look at the size of that wiring. The max power that size wire (and the fuse on that circuit) is able to handle is only about 40 watts. The warming power of a 40 watt heater isn't enough to de-gel anything, certainly not before the battery would be completely drained - assuming that the filter had gelled and that was why you were sitting with the key on and not running the engine.

It isn't needed. It isn't large enough to be capable of much of anything.

gollygeemister · **Posted:** Wed Jun 19, 2019 11:39 pm

I measured with an amp clamp and the current in the fuel heater circuit levels off around 8 amps. At 14V running that's 112 watts. Think about how bad a 100W light bulb burns your fingertips. That's a lot of heat going into the fuel. IMO it should be thermostatically switched based on ambient temp or fuel temp, but hey, it's not the only thing that Jeep left up to us to fix.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

geordi wrote:

You'd think so... But look at the size of that wiring. The max power that size wire (and the fuse on that circuit) is able to handle is only about 40 watts. The warming power of a 40 watt heater isn't enough to de-gel anything, certainly not before the battery would be completely drained - assuming that the filter had gelled and that was why you were sitting with the key on and not running the engine.

It isn't needed. It isn't large enough to be capable of much of anything.

gollygeemister wrote:

I measured with an amp clamp and the current in the fuel heater circuit levels off around 8 amps. At 14V running that's 112 watts. Think about how bad a 100W light bulb burns your fingertips. That's a lot of heat going into the fuel. IMO it should be thermostatically switched based on ambient temp or fuel temp, but hey, it's not the only thing that Jeep left up to us to fix.

The fuel heater is not simply used to keep fuel from gelling. It is also used to make the fuel a consistent temperature - and therefore a consistent viscosity - for proper injection and more complete combustion in the cylinders. This is a common feature in a lot of diesel fuel systems.

geordi - as usual - postulates on things he knows NOTHING about. He uses his rather limited observation skills and assumes things - usually incorrectly. gollygeemister just schooled you, geordi... he actually MEASURED the amount of electricity going into that heater, and anything over 100 watts is plenty of power to do the job.

That said, gollygeemister is incorrect when he states that the fuel heater should be thermostatically controlled. As I stated above, the heater needs to be on 100% of the time to provide the diesel fuel with consistent temperature and viscosity for the best injection and combustion possible.

The REAL fix is the installation of an in-tank lift pump, and the upgrade fuel filter head if needed.... I have had no problems with my original filter heads... so far.

flash7210 · **Posted:** Fri Jun 21, 2019 11:43 am

I think the fuel heater is kinda useless.
Its only in the top of the fuel filter. Wont do anything for the fuel in the tank or lines.
It is thermostatically controlled but has to remain immersed in fuel to keep from overheating.
The fuel temp sensor is the important one and is used by the ECM to determine injection quantity.
If the fuel gets too hot, the ECM will reduce fuel (and power).
Some of us have installed fuel coolers in the return line.

WWDiesel · **Posted:** Fri Jun 21, 2019 1:08 pm

flash7210 wrote:

I think the fuel heater is kinda useless.
Its only in the top of the fuel filter. Wont do anything for the fuel in the tank or lines.
It is thermostatically controlled but has to remain immersed in fuel to keep from overheating.
The fuel temp sensor is the important one and is used by the ECM to determine injection quantity.
If the fuel gets too hot, the ECM will reduce fuel (and power).
Some of us have installed fuel coolers in the return line.

And that is due to the CP3 working the fluid being supplied to the high pressure fuel rail which can add a significant amount of heat to the fuel.
This heated fuel is returned by the fuel pressure controllers back to fuel tank where eventually over time it can raise the fuel temperature significantly in the fuel tank which is being supplied to the injection pump. The higher fuel temperature makes the engine less efficient.
You would be amazed how hot the return fuel can become leaving the fuel rail/CP3. :shock:

That in a nutshell is why some install a fuel cooler in series with the fuel return line.
It is not because of the fuel heater in the filter head.....

flash7210 · **Posted:** Fri Jun 21, 2019 1:33 pm

Quote:

It is not because of the fuel heater in the filter head.....

Correct.
The fuel will get plenty hot all on its own.

gollygeemister · **Posted:** Fri Jun 21, 2019 9:16 pm

flash7210 wrote:

Quote:

It is not because of the fuel heater in the filter head.....

Correct.
The fuel will get plenty hot all on its own.

Which is why I installed a 25C snap switch in line with the fuel heater relay coil supply. Now it is only active below that temperature, and I don't have to remember to plug it in when winter comes around.

WWDiesel · **Posted:** Fri Jun 21, 2019 9:37 pm

gollygeemister wrote:

flash7210 wrote:

Quote:

It is not because of the fuel heater in the filter head.....

Correct.
The fuel will get plenty hot all on its own.

Which is why I installed a 25C snap switch in line with the fuel heater relay coil supply. Now it is only active below that temperature, and I don't have to remember to plug it in when winter comes around.

Neat Idea! Where did you get the switch and what's it's amp rating?

Weird CRD problem ??...

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