Idle surging in gear - EGR problem?

Glend · **Posted:** Thu Feb 18, 2010 6:45 pm

My KJ has developed a annoying habit of surging at idle in gear. It has a surging sort of miss happening at idle in gear. Its fine in Park or neutral but when in gear (and thus a little loaded) it displays an annoying stumbling surge. As soon as I take off from a traffic light or stop it goes away. In idling crawl situations offroad this is really annoying. Anyone have any ideas?
I have a new fuel filter, the fuel system has been bled several times now, and this happens on multi tanks of fuel. The vehicle is obsessively maintained and runs a Provent. When the Samco hoses were put on I inspected the FCV. My EGR pipe was replaced under warranty a couple of months ago. My scanner picks up no codes and no CELs at any time. At last minor service at Jeep dealer I reported it and they could find no codes with their system.

Is this evidence of an EGR valve failure or sticking? Injector problems? I can't work it out but want it fixed. :banghead:

MrMopar64 · **Posted:** Thu Feb 18, 2010 7:15 pm

Can you correlate when it started to some other activites with the vehicle? The idle is closed-loop controlled and the most important factors to the idle stability would be fuel system related, namely injection and rail pressure.

Does it it:
• warm idle in park?
• cold idle in park?
• cold idle in gear?

cmohr · **Posted:** Thu Feb 18, 2010 7:18 pm

What sort of RPM's Glen, has it always done it, or is it just a new thing??? Could be low revs, and the turbo boost not kicking in, then kicking on and out.??

Glend · **Posted:** Thu Feb 18, 2010 7:46 pm

It happens whether the vehicle is cold (first start) or warm and simply sitting at a traffic light. It only happens when in Drive or Reverse (never in Park or Neutral).

It has normal idle rpm (@750rpm) and this does not seem to change although there is a little wobble in the rpm when surging.

It does not do this above idle rpm it smooths right out, but as you can imagine when idling along in gear it is very annoying.

Boost has nothing to do with it as at idle there is actually abit of negative manifold pressure. When manifold pressure turns positive it goes away.

BTW all sensors are clean (MAF, MAP, etc).

linewarbr · **Posted:** Thu Feb 18, 2010 8:07 pm

Mine was doing something like this. . . sort of. It was a trans issue in mine. It happened when both the engine and trans were cold and I was idling in gear during a long wait at a McDonald's drive thru. It kept feeling as though the engine was kind of straining (not really lunging or stumbling) against the brake. At one point I let off the brake, heard a pop, and the Jeep started running weird, like it was in limp mode but with no CEL. Turns out I had too much trans fluid in it, I got a DTC for too high of line pressure in the trans. The pop I heard was my trans dipstick forcefully removing itself against the underside of the hood.

Unless you are convinced it is the engine, then check your trans fluid level, mine was high. FWIW, I find that the best way to get a reading on fluid level in this trans is to check it when it is dead cold. I had overfilled it by about a quart.

cmohr · **Posted:** Thu Feb 18, 2010 8:17 pm

Yeah, I was going to say, it sounds a little like the transmission , I have had similar in my auto, sort of like surging. Only other way I can discribe it is like being "Pumped" along.

Glend · **Posted:** Thu Feb 18, 2010 9:19 pm

Maybe making some progress. I disconnected the battery for one hour. After reconnecting it I did a test drive around the block a few times - idle surging problem has seemingly disappeared (and I knew that as soon as I put it in gear). Did a few test stops and started in gear and yep its gone (for now).

So WTF? I'm very leary of declaring it resolved but would like to know what was causing it. I'll keep a close eye/ear on the situation over the coming days. :5SHOTS:

cmohr · **Posted:** Wed Feb 24, 2010 10:47 pm

Hows it going Glen, any return of the symtoms???

linewarbr · **Posted:** Thu Feb 25, 2010 8:03 pm

I'm interested to see what ended up being the resolution as well. Here is a link to my issue. viewtopic.php?f=5&t=50040 I scanned the code immediately after it happened; I never had a CEL but still had a code.

Since getting my trans fluid level right, this has not reocurred.

liberty2.8 · **Posted:** Thu Feb 25, 2010 8:22 pm

Quote:

Since getting my trans fluid level right, this has not reocurred.

linewarbr, how did you get the extra fluid out? I changed my filters and fluid last week and I think I overfilled. I checked dipstick when cold and it shows full to the hot level. Also a symptom I have been experiencing when cold is a slight hesitation, like the brake is on, when shifting into gear. I put in a full 5 qts. but maybe should have went with 4 1/2 qts.
Hopefully, there is a way to remove the fluid through the fill tube but I dont have a vacuum pump.

BVCRD · **Posted:** Thu Feb 25, 2010 8:49 pm

liberty2.8 wrote:

Quote:

Since getting my trans fluid level right, this has not reocurred.

linewarbr, how did you get the extra fluid out? I changed my filters and fluid last week and I think I overfilled. I checked dipstick when cold and it shows full to the hot level. Also a symptom I have been experiencing when cold is a slight hesitation, like the brake is on, when shifting into gear. I put in a full 5 qts. but maybe should have went with 4 1/2 qts.
Hopefully, there is a way to remove the fluid through the fill tube but I dont have a vacuum pump.

I have read of a guy putting a 1/4 inch plastic hose down the tube, and siphoning it out over night. It is slow going but might do the trick for you.

Glend · **Posted:** Fri Feb 26, 2010 6:05 am

After a few days the symptoms returned but not as often or as noticable.

Baffles me.

My transmission fluid level is spot on the mark. I was having my surge problem before I installed the auxiliary transmission cooler, so minor fluid level changes don't seem to be causing the problem.

My next step is to try and disable the EGR and see if that affects the problem. I am waiting for SAKJ to send me some info on how he did that in Adelaide.

BTW there are small hand pumps sold by boat shops that can pull oil out of the dip stick tube. Its used on inboard boat engines where you cannot get under the pan to drain the oil.

linewarbr · **Posted:** Fri Feb 26, 2010 9:38 am

Glend wrote:

After a few days the symptoms returned but not as often or as noticable.

Baffles me.

My transmission fluid level is spot on the mark. I was having my surge problem before I installed the auxiliary transmission cooler, so minor fluid level changes don't seem to be causing the problem.

Glen, as far as the tranny goes, you may be having problems with the pump. Since yours is an 07 (not sold here) I'm not sure what torque converter/ pump you have and whether or not it was subject to F37 recalls. Part of F37 was to install a different-style trans pump. I hope you identify whatever the problem is and get it fixed. Please keep us posted.

liberty2.8 wrote:

Quote:

Since getting my trans fluid level right, this has not reocurred.

linewarbr, how did you get the extra fluid out? I changed my filters and fluid last week and I think I overfilled. I checked dipstick when cold and it shows full to the hot level. Also a symptom I have been experiencing when cold is a slight hesitation, like the brake is on, when shifting into gear. I put in a full 5 qts. but maybe should have went with 4 1/2 qts.
Hopefully, there is a way to remove the fluid through the fill tube but I dont have a vacuum pump.

I did similar to what Glen said - I went to Advance and bought a siphon pump with an inline squeeze-ball and an included 6 feet of tubing for $5. I used the length of the dipstick to mark the necessary depth on the tube, since when I had the pan off I saw that the dipstick nearly touches the pan. I tried using the hand pump, but it didn't have enough suction, so I had to go the old-fashioned route - mouth-to-mouth resuscitation. I ended up removing just a little under a quart by sucking transmission fluid up into the squeeze ball, then putting my finger over the top opening where I was sucking, pulling the tube out of the tranny, and draining it into an empty quart container I had handy. It was slow going but I didn't have a whole lot to remove. If I had had more tubing I could probably have gotten a true siphon going, but I wasn't trying to drain the transmission, just remove a little fluid.

On a side note, you know how trans fluid smells? Yeah, it doesn't taste much better. And it takes some serious suction to pull cold tranny fluid up and out like that. My mouth and gums were sore the next day or two.

And please, no "that's what she said" posts. . . . . :roll:

BVCRD · **Posted:** Fri Feb 26, 2010 9:47 am

linewarbr wrote:

Glend wrote:

After a few days the symptoms returned but not as often or as noticable.

Baffles me.

My transmission fluid level is spot on the mark. I was having my surge problem before I installed the auxiliary transmission cooler, so minor fluid level changes don't seem to be causing the problem.

Glen, as far as the tranny goes, you may be having problems with the pump. Since yours is an 07 (not sold here) I'm not sure what torque converter/ pump you have and whether or not it was subject to F37 recalls. Part of F37 was to install a different-style trans pump. I hope you identify whatever the problem is and get it fixed. Please keep us posted.

liberty2.8 wrote:

Quote:

Since getting my trans fluid level right, this has not reocurred.

linewarbr, how did you get the extra fluid out? I changed my filters and fluid last week and I think I overfilled. I checked dipstick when cold and it shows full to the hot level. Also a symptom I have been experiencing when cold is a slight hesitation, like the brake is on, when shifting into gear. I put in a full 5 qts. but maybe should have went with 4 1/2 qts.
Hopefully, there is a way to remove the fluid through the fill tube but I dont have a vacuum pump.

I did similar to what Glen said - I went to Advance and bought a siphon pump with an inline squeeze-ball and an included 6 feet of tubing for $5. I used the length of the dipstick to mark the necessary depth on the tube, since when I had the pan off I saw that the dipstick nearly touches the pan. I tried using the hand pump, but it didn't have enough suction, so I had to go the old-fashioned route - mouth-to-mouth resuscitation. I ended up removing just a little under a quart by sucking transmission fluid up into the squeeze ball, then putting my finger over the top opening where I was sucking, pulling the tube out of the tranny, and draining it into an empty quart container I had handy. It was slow going but I didn't have a whole lot to remove. If I had had more tubing I could probably have gotten a true siphon going, but I wasn't trying to drain the transmission, just remove a little fluid.

On a side note, you know how trans fluid smells? Yeah, it doesn't taste much better. And it takes some serious suction to pull cold tranny fluid up and out like that. My mouth and gums were sore the next day or two.

And please, no "that's what she said" posts. . . . . :roll:

LOL. That's funny. Reminds me of a story. I was fishing in Alaska offshore, and we never took time out for meals. We would punch a hole into a can of tomatoe soup and suck it out with a straw. That'll make you pucker.

danoid · **Posted:** Fri Feb 26, 2010 2:19 pm

Glend wrote:

After a few days the symptoms returned but not as often or as noticable.

Baffles me.

My transmission fluid level is spot on the mark. I was having my surge problem before I installed the auxiliary transmission cooler, so minor fluid level changes don't seem to be causing the problem.

My next step is to try and disable the EGR and see if that affects the problem. I am waiting for SAKJ to send me some info on how he did that in Adelaide.

BTW there are small hand pumps sold by boat shops that can pull oil out of the dip stick tube. Its used on inboard boat engines where you cannot get under the pan to drain the oil.

Please define 'spot on the mark'. The fill level varies with the temperature of the oil.

Yes the hand pumps are a good way of removing excess fluid.

Glend · **Posted:** Sat Feb 27, 2010 9:30 pm

As outlined above I have had some recent problems with a rough stumbling idle and surging at crawl speeds in gear. Jeep couldn't find a problem (no codes). My KJ is still under warranty. I tried a couple of things, including a complete power down of the vehicle (battery disconnect), and this help for a few start cycles then the problem returned (slightly improved). Last night I did the ORM and in testing today the rough idle and surging is completely gone. Event through mulitple start cycles it runs great.

My question now is:

Is this a symptom of a failing EGR? Should I return it to normal and hope that it fails soon so that I can get it replaced under warranty? or just forget about it and leave the MAF unplugged until such time as GDE arranges their distributor in Australia?

Idle surging in gear - EGR problem?

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