KJ Died, but runs fine, whats up!

Franko · **Posted:** Fri Apr 10, 2015 4:12 pm

Back story, last Monday buddy and I are taking the kids out to the woods to play. Turn onto the HWY and throttle down, jeep hiccups and starts to run real rough.
So I pulled over, and shut her down right away, got out looked under the hood everything looks fine.
So i jumped back in and flashed her up, bam! purrs like a kitten and runs great. We set back on with our trip and the jeep runs great the rest of the day and from then on forth.

So the nagging question is, what the heck went wrong. I wanna get to the bottom of it before it happens again. Could it have been the trans acting up?

06 KJ Diesel with 145KM not Miles.

flash7210 · **Posted:** Fri Apr 10, 2015 4:19 pm

Sounds like the typical air in fuel problem.

dan86 · **Posted:** Fri Apr 10, 2015 4:23 pm

Does sound like it. But odd how it just started working fine instantly without any intervention. do you ever have issue with starting?

2003 KJ Liberty 2.5 CRD

flman · **Posted:** Fri Apr 10, 2015 4:38 pm

dan86 wrote:

Does sound like it. But odd how it just started working fine instantly without any intervention. do you ever have issue with starting?

2003 KJ Liberty 2.5 CRD

That is how it usually happens. You already threw a bad condition at the computers, so restarting it puts every thing back in sync for the time being that is.

UFO · **Posted:** Fri Apr 10, 2015 4:59 pm

I had a similar symptom once, sounded like it was running on two cylinders. I had freaked out the engine or tranny computers by coasting in neutral. We all know how the CAN bus in these vehicles can hardly tolerate an OBDII analyzer. Once I turned off, it re-started and ran fine.

geordi · **Posted:** Fri Apr 10, 2015 6:14 pm

OBD scanners cause the transmission computer to "throw up its hands" and reboot suddenly - since the overdrive is electronically activated, this rebooting while driving causes the transmission to slam down 2 gears into 3rd gear. Usually quite violently. If it happened while you were coasting, the likely result was the transmission computer also lost count of where the selector was, and that threw off the fuel map for the engine.

To the original poster: When was the last time you replaced the fuel filter? What you describe is also the symptoms of a clogged filter.

Franko · **Posted:** Sat Apr 11, 2015 12:19 am

Thats just it! I only just replaced the fuel filter like 2 months ago.

So it seems weird that it would be the fuel filter??

It sure seemed like a couple of cylinders dropped died, or that's what it sounded like.
Got my heart pumping real good lol

Anyway hope it doesn't happen again, maybe I should flush out the trans and change the fluid.

geordi · **Posted:** Sat Apr 11, 2015 1:01 am

Unlikely that it has anything to do with the transmission. Engine stumbling is entirely a separate issue and 95% plus that it is fuel related.

With the changeover from winter to summer fuel it could also be fuel contamination, the stations may have contaminated their own fuel (not on purpose) and the fuel filter can easily suffer because of that. Drain from the bottom of the filter into a small glass container and let it sit for a bit - see if anything separates out and there's your answer. Pre-filling your filter with Power Service silver (summer) will help clean out your fuel pump and injectors and the excess will push back to the tank and help there.

Power service is never a bad thing to dump into your tank in large dosages.

flman · **Posted:** Sat Apr 11, 2015 7:58 am

Usually a filter can be changed on calendar and mileage. All it takes is one bad fill up and you need to change it again. Mine gets a new filter with each oil change. If the engine gets a hiccup before the next oil change it gets a new filter, unless I am sure it was an air related problem.

KC-CRD · **Joined:** Wed Jan 28, 2015 2:20 pm **Posts:** 47

This sounds exactly like what mine did a few weeks ago. For me I had driven less than 1/4 mile from home. Stopped at a light and it started running really rough. When it didn't settle down after a few seconds, I shifted into reverse planning to turn around and go back home and it died. I restarted it and haven't had any trouble since. I have a 90 mile commute so I've driven at least 1000 miles since with no problem.

Before it died I was wondering if I pushed my luck too far on the timing belt. I have 175k miles on it and no records if the belt has ever been changed. But once it restarted I started considering air in the fuel or an electrical problem. I had a new windshield installed by an idiot a couple years ago, and it leaks letting water run across the relay panel under the dash. I've had to replace the horn relay and occasionally lose cruise control when it rains. And it was raining the day I had the problem.

I'm adding Diesel Clean when I get fuel and I'm going to replace the fuel filter as part of normal maintenance. But unless it happens again I don't think I'll spend much more effort trying to chase it down. One anomaly in 30k miles.

geordi · **Posted:** Sat Apr 11, 2015 12:39 pm

Uhm... 175k miles, and you haven't gotten the belt replaced? :shock:

You DO know that I'm the traveling mechanic that works on these, right?
I'm also WAY cheaper than a dealership, and have worked on over 40 of these - and changing the belt is cheaper than having to replace all the rockers if the belt snaps.

KC-CRD · **Joined:** Wed Jan 28, 2015 2:20 pm **Posts:** 47

175k miles and an unknown maintenance history. I've had it for 30k and the timing belt has been on my todo list for a while. If someone has already been in there then I'm probably good. If not, it was 45k overdue when I bought it and I've been rolling the dice since day 1. The parts are sitting here, but the garage is full of the other things life throws at you. Its looking like once I get my hubs/halfshafts replaced (and the garage cleaned so I can reach my tools) there will actually be time to finally do the belt.
Now I'm just praying none of the lawn equipment breaks before summer. :juggle:

HER_CRD · **Posted:** Sat Apr 11, 2015 8:45 pm

I had this exact same thing happen yesterday. My wife has noticed a hiccup or two herself but never had it shut down.

Does anyone have a lift pump on their tank? Been thinking of putting one in.

dan86 · **Posted:** Sun Apr 12, 2015 2:38 am

It would seem a lot of people do. I'm going to be fitting one in the next 4 weeks.

2003 KJ Liberty 2.5 CRD

gmctd · **Posted:** Sun Apr 12, 2015 5:36 am

HER_CRD wrote:

I had this exact same thing happen yesterday. My wife has noticed a hiccup or two herself but never had it shut down.

Does anyone have a lift pump on their tank? Been thinking of putting one in.

REPEAT FUEL DELIVERY PART # QUESTIONS

Revised Fuel Filter Head kit - 68043089AA with filter and wire\plug adaptor
Wiring\Adaptor Plug - 68043086AB
Fuel Filter - 52129238AA (NAPA: FIL 3647, WIX: 33647)

Cummins in-tank lift pump
CARTER P76148M
AIRTEX E7181M
DCJ (P)52121447AD

12v external in-line lift pump
AIRTEX E8251 3-5psi for pre-filter mounting near fuel filter head
FACET 40109 12-15psi best for pre-filter mounting near fuel tank

All items can usually be found on eBay

Pictorial showing replacement to upgraded filter head:
- viewtopic.php?f=5&t=64260

Pictorial showing installation of Cummins in-tank lift pump:
- http://www.auerbach.ca/kj/lift_pump/

Posted R&D of factory in-tank lift pump installation
- viewtopic.php?f=5&t=25447
__________________________________________________________________________________________________

WWDiesel · **Posted:** Sun Apr 12, 2015 10:02 am

HER_CRD wrote:

I had this exact same thing happen yesterday. My wife has noticed a hiccup or two herself but never had it shut down.

Does anyone have a lift pump on their tank? Been thinking of putting one in.

There are a bunch of us on this forum who have installed a lift pump; some went the in-line route while many others did the in-tank install. Both options will cure air in fuel problems if installed properly. I personally like the in-tank option as it puts everything under pressure from inside the fuel tank all the way to the injection pump. Any leak of any kind will show up real fast as a fuel leak!!! :wink:

Be sure that what ever kind of pump you opt for that it will allow fuel to pass through it if it fails or loses power!!!

As to hiccup's; if it is happening during the engine warm up periods, it could possible be a crank sensor going bad? They are notorious for going bad with age and causing problems as they go from cold to normal engine temperature... There is information on this forum on how to test and / or replace the CS. Just do a search.... :idea:

HER_CRD · **Posted:** Sun Apr 12, 2015 10:14 pm

Thanks for the info guys. I'd much prefer to do the in tank pump to avoid the leaks on the suction side. All three options would fit an 05 CRD?

Haven't noticed any hiccups during warm-up yet so thanks for the tip.

gmctd · **Posted:** Mon Apr 13, 2015 12:04 am

HER_CRD wrote:

Thanks for the info guys. I'd much prefer to do the in tank pump to avoid the leaks on the suction side. All three options would fit an 05 CRD?

Haven't noticed any hiccups during warm-up yet so thanks for the tip.

All three are oem CARTER - AIRTEX and DCJ are merely peddlers..............

HER_CRD · **Posted:** Mon Apr 13, 2015 6:22 am

Awesome. Is there a physical difference between the first and second generation filter head? I'm not sure this has been changed.

papaindigo · **Posted:** Mon Apr 13, 2015 8:36 am

1s gen filter head has 2 upper electrical plugs one noticeably smaller than the other; small one is heater element. 2n gen head has same 2 plugs but both about the same size and the new electrical plug is bright blue; see bleeding how to and video at viewtopic.php?f=5&t=54207

KJ Died, but runs fine, whats up!

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