UPDATE: please read! Dieseling? What causes that?

[porkchop]

As many of you know I just put in the new engine and it is running great :D . I drove it to work today for the first time and it was great going there no problems. After driving home, about 12 miles, I shut it off and it dieseled for about 2 seconds. Hmmmmm... I drove up to the store to get gas and it didn't do it at the gas station but then when I got home it did it again. I am sure it has something to do with a warm engine. This engine has NO emissions and it has the performer 2131 and 1405 carb. Any suggestions.

[ June 04, 2002: Message edited by: porkchop ]</p>

[nightflyers]

When mine was diong it, it was because the idle was a little high.

[shadowfax101]

same here, when my idle was set to high I would have that problem

[PhilSine]

Funny thing about that.......

Mine just did that today too. I just called my Jeep Mentor and asked him why. He said it's because the butterfly on the carb is not closing all the way when I shut it down. Sure enough, That is it. Now I just need to figure out what I did in the rebuild a month ago to make it so the carb won't shut all the way (I noticed it immediately but it all ran great so I left it). Also, as a result of the butterfly not fully closing I can't get my idle down to normal.

[jeepbob]

That is why there is an anti-run-on solinoid that will keep the idle up when the key is on and then drop it down real low when the key is turned off. Just lower your idle speed and you should not have any more problem.

[Lindel]

Timing that is advanced too far can do it, also. But the most common cause is too high of an idle.

It never really used to be a problem, until the Feds demanded that pollution controls be installed on all vehicles. Not that we need pollution, but the engineers of the time didn't really know what they were doing, and to keep the engines running, after installing all the pollution junk, they upped the idle speed, only to find that run on became a common problem.

[Eric S.]

Caron buildup in the cylinders is another common problem that causes dieseling. The junk that builds up in there stays hot after you turn off the engine, and that causes fuel to detonate without spark.

The fix for that is pretty simple: add some detergent-type fuel cleaner in your gas tank every so often. Also, don't be afarid to run some high rpms from time to time (i'm not kidding). It tends to loosen the crud inside your engine.

[PhilSine]

I don't have an anti run-on solenoid on my Holley. I can feel a mechanical obstruction in mine. Timing is good. Idle set screw is out as far as it can go. I just have to pull the carb again & figure out what is hanging up the butterfly.

[Midnightwagon]

hey porkchop give me a call i dont know much about jeeps but i can tune a motor it sounds like to me your idle mixturs screws on the edelbrock are not tuned correctly so to get to idle the idle speed screw is cranked to fer in

[dennis w helt]

my jeep doesnt do that but my truck does its cuz of carbon and a fast idle use a high octane and it will go away

[porkchop]

Thanks for the replys guys. I am pretty sure that it is due to the timing being off. I am also getting this wierd sound when I first start out in the jeep. It will only do it until it gets warm. It sounds like metal squeaking like if you had a loose bolt. It would only do it under load. If I take my foot off the gas it goes away. I know it is not a bearing because it would do it all the time, and/or get worse with the heat. I ask the local mechanic on base and he was telling me that the timing being to far adavanced can cause that sound. When I get home today I checked the timing and it is good at idle,10 btdc but at 3000 rpm's it is at advanced about 51*. Is this normal? So I am going to go over it tomorrow and check everything out real good and see what is going on.

[irbob]

PC...did you get my email?

Thats why you set your timeing at normal idle with vac advance off and pluged and at running temp. It will advance at higher RPM's. That engine looks sweet. I like the red. Give it some time to break in to get all the bugs outa it.

[porkchop]

I got your email but haven't had a chance to fire one back yet.

I did set my timing in that way. I am also suspecting water pump bearing.

[irbob]

Do you have a Mechanics stethiscope? It goes in your ears down to a long rod that you touch engine parts to listen for grinding noises, ticking and such. If not you can use a looooonnnnggggg screw driver. Touch the suspect parts with the tip and put the handle up to your ear. Kind of like putting a glass on a wall to listen whats going on in the appartment next door. :D A seasoned mechanic can tell the sound of a bad bearing/bad valves in what cylinder, etc.

I like to get my stethiscope out some times and listen to my 360's heart beat. :D :rolleyes:

[porkchop]

Yes I did that. I used a broom stick. works just as well. The only bad thing about it is that it only really happens under load. I would need a loooooonnnnnnggggggeeerrr screw driver for that.