89 Wrangler, won't idle

For some reason, mechanics seem to forget (or they aren't old enough to know, LOL) that a carb is supposed to get a rebuild kit every time you change the spark plugs/cap and rotor.

A kit for that carb is about twenty bucks and is easy to put in.

While you are in there, you will find these two brass tubes with crimped ends that have plugged up. The crimps are too small and need to be physically reamed to get them clean, chemicals just won't do it. I use a set of welding torch tip files for cleaning them. These files are cheap and metered sizes.

Here is a decent write-up on cleaning the idle tubes:

You 'can' also disable the computer to get increased performance and to kill the governor that stops the rpms at 3500, but you should address the carb first.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

TSMaxel wrote:

I also have a 1989 Islander. Don't take the emissions junk out, you'll never get it to run right. Bring it to a shop to have a new carb put in. Mine's in the shop now, $300 for a rebuilt unit. My carb got so bad (leaking) that when I used the brakes the engine would die.

My carb was running rich also. When I took the air cleaner off while it was (trying to) idle, when you looked down the carb... the jets would spray fine when the gas was pressed, but one jet would leak at idle too badly. It would leak that bad even when it was set as lean as it could be. This made the Jeep run very rich.

When you have your carb put in, have them put in a new EGR valve as well. This should be replaced every 80k miles. There is a timer that sets the Check Engine light off to tell you to change the EGR, but I'm sure that was ripped out a long time ago.

-Mark

Where are you located? There is a great mechanic that does a great job with Jeeps in Schenectady New York.

Man, that is the typical plugged up idle tube that happens to 'all' of the Carter BBD's eventually.

It is an extremely easy fix that I can do on the side of the trail in less than 15 minutes.... for free.

Putting a carb kit in and giving it a good clean like you are supposed to do every main tune up does them wonders.

And the timer is only for the O2 sensor, not EGR.

And your 'mechanic' is 'only' good at seeing a sucker coming....

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Mark12211 wrote:

Oh man, where to start....

Your Jeep was running too lean. Most likely one or both idle tubes plugged. When this happens it idles rough and stalls. So, not knowing any better, you raise the idle, opening the throttle enough to start 'siphoning' fuel through the venturi. Then you mess around and lean it "as lean as it could be", making things worse. Then you open the throttle more, causing more siphoning. Seeing the fuel "leaking", you assume it's rich. Nope.

In steps 'super mechanic' and:

You've now paid for a new EGR valve that, if replaced solely because of mileage, you didn't need.

Congratulations, you've been had.

Replacing the carb will fix one problem, but if he's replacing it because he thought it was rich, he's fixing it by accident.

Thanks for the warning.

Springfield Ohio... A little far to drive for a carb rebuild. However, the info you have given is great. Sounds just like what we are seeing. Carb rebuild, EGR valve and we will go from there. Thank you very much.

TMax

Well, I never claimed to be a mechanic and this is good news / advice! The web sites are very helpful and I appreciate your help!

My son and I will be cleaning the carb and we are sure this is our problem. I am not a "mechanic", but my boys have race MX for year so I have learned all about 2 strokers and do all our work on the bikes. My oldest son is getting his license and the Jeep is his baby. We want to be able to do these types of things ourselves, but had no clue with this idle thing. These sites you passed along helped a lot!

If you don't mind me asking a couple more questions...

When you bypass the computer can the cat be removed? In otherwords, can we install a header, pipe, muffler and tailpipe eliminating the cat converter? If the computer stays "asleep", I would imagine some of the sensors could be eliminated or bypassed without effecting performance. True?

Again, appreciate your help.

TMax

When you do the carb, just don't unscrew anything that you don't need to to clean it.

My 86 CJ7 didn't come with a cat, not needed up here on a utility vehicle and it runs fine. I don't think you are allowed to remove a cat in the USA if it comes with one, but that really depends on your driving area if it would ever get checked I guess.

When I put the computer out of my misery, I removed about 2 miles of vacuum lines and related junk.

I still need to pass emissions, so I left in my EGR valve, air filter hot air flaps (prevents carb icing at freezing temps) and the gas tank vent or charcoal canister and PCV system.

Mike

TSMaxel wrote: