Limp Mode -> running VERY rough on 1 Cylinder -> died

Endurance · **Posted:** Sun May 04, 2008 3:17 pm

Yesterday I had something REALLY strange happening. This happened to me only ONCE before, about a year ago.

I was driving down the road and as soon as OD kicked in at 50mph the Jeep had zero throttle response. I coasted to a stop and the entire Jeep started shacking because it was running so rough. I turned it off and back on, same thing. After trying to restart it again, it wouldnt even turn over. I popped the hood, looked for loose connections and plugged MAF in (up until then I had been running ORM). Surprisingly, the Jeep fired right up and ran like nothing ever happened.

I left the MAF plugged in to see if I get any codes, nothing. What I noticed though was that the engine is running smoother with the MAF plugged in. Also, when I turn it off, the engine used to shake kinda rough for the last 2 revolutions, which is normal I guess. When I turn it off now however it hardly shakes at all. WEIRD

Cowcatcher · **Posted:** Sun May 04, 2008 4:39 pm

Air in fuel.

warp2diesel · **Posted:** Sun May 04, 2008 5:56 pm

I second Cowcatcher's motion.
No CEL no limp mode, just air in fuel, CRDs run on #2 not air.

dgeist · **Posted:** Sun May 04, 2008 6:18 pm

I've had this happen twice on me, once just after filling up on B100 that had been stirred-about quite a lot and got a lot of O2 mixed up in it. I was running the ORM at that time and plugged it back in just for kicks. A few rough start/stop cycles later and it was fine. It happened again not too long ago and I have the SEGR, now. Same circumstances, same fix (stop/bleed/start, repeat if necessary).

Dan

BlackLibertyCRD · **Posted:** Sun May 04, 2008 9:19 pm

I think it's time for a lift pump to keep air out of the fuel head. Fuel under vacuum equals air at high point of fuel head. Try it, you will like it.

Endurance · **Posted:** Sun May 04, 2008 11:08 pm

Thanks for the help guys. I will bleed the lines first thing tomorrow.

Endurance · **Posted:** Tue May 06, 2008 11:13 pm

What I dont understand though is why my CRD idles MUCH smoother with the MAF plugged in. If I unplug it, the engine sounds like its under more strain and the diesel knocking sound is much louder.

warp2diesel · **Posted:** Tue May 06, 2008 11:28 pm

The EGR is used to lower the flame front temperature and reduce NOX emissions, this also slightly reduces the diesel clatter. The reason we do the ORM is to not reduce the oxygen level in the cylinders and increase fuel economy by 2-3 MPG. With $4 + fuel cost, 2-3MPG helps the bank account and putting up with a tiny bit more noise is a small price to pay. As far as NOX goes, most members feel that the jury has not had time to evaluate the Facts Vs Theory about NOX and the ULSD or Biodiesel may lower the NOX emissions enough to make the EGR useless.
Since you had your CRD die on you, it would be smart to install a lift pump. On my CRD it got rid of the mid to high RPM loss of power and stumbling. The VM 2.8L is a true diesel designed to run with out the EGR as well as with it. The load you put on the pistons, connecting rods, and crank under even normal acceleration is much more load than what the diesel clatter creates on these components.
Like the song goes, "Don't worry, be happy" after all you have a CRD.

Steve

dieseldawg · **Posted:** Wed May 07, 2008 9:43 am

I had this rough running happen once a couple weeks ago. I was sitting at a stop sign waiting to make a right turn. Seemed to be idling fine, hit the accelerator and had normal throttle response then as I finish making the 90 degree turn, I lost all power and had to coast to the side of the road. It continued to run, but idling real low, 500 rpm, and very roughly. Turned it off. Restarted. Still running rough. Turned off, Restarted. Still running rough. Third time, turned it off, let it sit about 10 seconds, then started, ran like nothing happened for 2 hours no problem driving through the hills of PA leaving for a camping trip. It has not done it since, and there were no codes thrown. I am running ORM all the time. I also have had the Cummins fuel pump installed for about 3500 miles with no problems. I'm at a loss for what happened. It was definitely bizarre.

dgeist · **Posted:** Wed May 07, 2008 5:33 pm

dieseldawg wrote:

I had this rough running happen once a couple weeks ago. I was sitting at a stop sign waiting to make a right turn. Seemed to be idling fine, hit the accelerator and had normal throttle response then as I finish making the 90 degree turn, I lost all power and had to coast to the side of the road. It continued to run, but idling real low, 500 rpm, and very roughly. Turned it off. Restarted. Still running rough. Turned off, Restarted. Still running rough. Third time, turned it off, let it sit about 10 seconds, then started, ran like nothing happened for 2 hours no problem driving through the hills of PA leaving for a camping trip. It has not done it since, and there were no codes thrown. I am running ORM all the time. I also have had the Cummins fuel pump installed for about 3500 miles with no problems. I'm at a loss for what happened. It was definitely bizarre.

How old is your fuel filter? Might be partially blocked and cycling it a few times and letting it sit knocked enough CRuD free. The slow idle sounds like fuel starvation to me.

dieseldawg · **Posted:** Thu May 08, 2008 8:40 am

The fuel filter was put on new when I installed the lift pump. So the filter has about 3500 miles on it. It is the CAT 2 Micron filter, so maybe I got a tank of dirty fuel, but I fuel at the same places. To me it seemed like it was starving for fuel. I have a fuel pressure gauge installed after the filter, and while it was doing this, I looked at the gauge and I still had 9 psi like I normally do. I'm just wondering if I picked up a pocket of water or something, sitting in the fuel filter. Just a guess.

Limp Mode -> running VERY rough on 1 Cylinder -> died

Who is online