Diesel Engine issue tracking thread... also please post if NO issues!

[Teqsand]

12234 miles and no issues so far. Started using Hot Shots EDT around the 8k mark. Changed fuel filter at 10k.

Wife 21 JLURD has 33k and didn't change fuel filter until 30k. lol

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[Almost]

Wife 21 JLURD has 33k and didn't change fuel filter until 30k. lol

How did it look? I changed mine out a tad before 15K and it was fine and will be going to 20K next. It seems Mopar was pretty conservative with interval which is a good thing.

 

[Teqsand]

How did it look? I changed mine out a tad before 15K and it was fine and will be going to 20K next. It seems Mopar was pretty conservative with interval which is a good thing.

It was grey (and wet), but reasonable honestly.... depends on the fuel more than anything i suppose, otherwise it's hard to get dirt in to tank.... I wouldn't have an issue going to 20

 

[Sprinkler-Fitter]

This is a well thought out poll. I don’t have the diesel but I’m watching the thread because I’m a stat nerd.

I wonder if any of it is any use though. I would guess more Jeep owners don’t use a forum than do use a forum.

 

[DailyMoparGuy]

I wonder if any of it is any use though. I would guess more Jeep owners don’t use a forum than do use a forum.

Yea it’s definitely a small sample size haha. Something is better than nothing though I suppose.

 

[StrictNine]

I had a cracked flange on the turbo fixed around 17k, 19k now. Didn’t throw any codes, but the exhaust would burn your eyes if it was started in the garage and the mileage seemed to suffer. Dealership suspected it was overtorqued from the factory. They had to pull the cab. Took 5 days to get it fixed when they finally had parts.

I still feel like the exhaust isn’t as clean as my Cummins. But maybe that’s just how these are.

 

[Zybane]

I'm about to replace my first fuel filter at 10K miles and had a thought. Since air in the lines can cause problems with the CP4, what if I pre-filled the filter housing with diesel when replacing the filter? This should really minimize air having to go through the lines.

I know the owners manual says not to do it because of risk of contamination, but I'm usually pretty good about stuff like that (wipe everything down, use only a new/clean container for the diesel fuel etc). The fuel filter housing has a surprising amount of volume for air to get trapped/compressed as the fuel tank pump tries to prime it after filter change.

 

[Bananaman]

I'm about to replace my first fuel filter at 10K miles and had a thought. Since air in the lines can cause problems with the CP4, what if I pre-filled the filter housing with diesel when replacing the filter? This should really minimize air having to go through the lines.

I know the owners manual says not to do it because of risk of contamination, but I'm usually pretty good about stuff like that (wipe everything down, use only a new/clean container for the diesel fuel etc). The fuel filter housing has a surprising amount of volume for air to get trapped/compressed as the fuel tank pump tries to prime it after filter change.

Interested in this question myself.

 

[Zybane]

Since the fuel filter "bottom cap" is quite small, instead of filling that cap with diesel before screwing the filter and cap back on, what if I were to slightly crack open the water drain plug while priming the system?

So it would go something like this:

1. Replace fuel filter.
2. Screw fuel filter cap tightly back on.
3. Without starting the engine, do one entire prime cycle for fuel to enter fuel filter housing from lift pump and increase pressure.
4. Crack open water drain valve slightly to let air (and some fuel) out.
5. Repeat a few times to get as much air out as possible.

My logic is that instead of having an entire fuel filters housing worth of compressed air having to go through the CP4, that possibly opening the water drain valve could let quite a bit of that air out.

Thoughts?

I've decided to let the fuel filter go the recommended 20K miles before changing it and just draining the water at my 10K mile oil change I'm doing this week. (Also replacing diff fluids).

Doing the fuel filter every 20K instead of 10K means half as much air being run through the CP4 over its life.

 

[IPRoutes]

Since the fuel filter "bottom cap" is quite small, instead of filling that cap with diesel before screwing the filter and cap back on, what if I were to slightly crack open the water drain plug while priming the system?

So it would go something like this:

1. Replace fuel filter.
2. Screw fuel filter cap tightly back on.
3. Without starting the engine, do one entire prime cycle for fuel to enter fuel filter housing from lift pump and increase pressure.
4. Crack open water drain valve slightly to let air (and some fuel) out.
5. Repeat a few times to get as much air out as possible.

My logic is that instead of having an entire fuel filters housing worth of compressed air having to go through the CP4, that possibly opening the water drain valve could let quite a bit of that air out.

Thoughts?

I've decided to let the fuel filter go the recommended 20K miles before changing it and just draining the water at my 10K mile oil change I'm doing this week. (Also replacing diff fluids).

Doing the fuel filter every 20K instead of 10K means half as much air being run through the CP4 over its life.

You would be better off changing the fuel filter every 20k miles but draining water every 5k miles.

 

[Jefe1018]

I think the pre filling or extra steps to purge are a good thought, but these are self priming system. If you follow the process for running the fuel pump a solid 20 times after putting the new filter in, you shouldn’t have an any problems.

 

[Zybane]

I think the pre filling or extra steps to purge are a good thought, but these are self priming system. If you follow the process for running the fuel pump a solid 20 times after putting the new filter in, you shouldn’t have an any problems.

Ya but that air has to go somewhere, no matter how much you prime. Just watched a Youtube video of a guy that primed 12 times, and had a good 4 seconds of engine turnover before starting.

 

[Jefe1018]

Ya but that air has to go somewhere, no matter how much you prime. Just watched a Youtube video of a guy that primed 12 times, and had a good 4 seconds of engine turnover before starting.

Isn’t that the point of a self air purging system though? Thought that meant it disposed of the air in the lines itself.

 

[Zybane]

Isn’t that the point of a self air purging system though? Thought that meant it disposed of the air in the lines itself.

Ya that's a good point... is there a return line from the filter housing back to the fuel tank. I'll see if I can find a schematic.

Not sure there could be, as it would fight with the return line from the fuel rail on the engine.

EDIT: This thread has a ton of pics:

https://www.jlwranglerforums.com/fo...on-trail-broken-fuel-separator-housing.76789/

So the fuel filter housing only has two connections, one way in and one way out. So all the air in that housing has to go through your CP4.

 

[Jefe1018]

Ya that's a good point... is there a return line from the filter housing back to the fuel tank. I'll see if I can find a schematic.

I’m mostly trying to speak logically from prior experience as I also don’t have any schematic or official procedures from Mopar. However, most forum posts I’m reading seem to indicate that there is a smart purge feature, one guy even said he’d forgot to let his off the brake and it cranked for 10-15 seconds before it started.

In my 24 valve Cummins you would run the fuel pump and leave the fuel cap off, you would hear the air come back up as the air is pushed backed out when the fuel lines were pressurized. I had a lot of experience with this, I’d rebuilt the engine from the block back up and getting the damn thing to start took me forever - mostly because I forgot the o-ring on 3 injectors somehow. I primed that sucker over and over to the point I knew that system inside and out before I realized my doh moment.

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