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Unread 04-09-2004, 10:07 PM   #1
amg61
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1990 YJ Wrangler 
 
Join Date: Apr 2004
Posts: 290
90 YJ cold idle blues

first of all, i am not a mechanic, but i have read as much as any sane person can on the topic of the YJ wrangler and the carter 258 idle problems. i have a 1990 yj, 6 cylinder, 4.2L, 5-speed manual transmission. from the MOMENT i bought this jeep 14 years ago, in feb. 1990, i have had idle and stalling problems. to give further details, i bought this car in California, with all their extra emission standard nightmares, though now i live on the other coast, 3 thousand miles away. the first week i owned it, every time i came to a stop at the bottom of my VERY steep driveway, the jeep would stall. back to the dealer it went, and adjustments were made that cleared this problem up, though i think the jeep then continued to idle no lower than 1000-1100 rpms. anyway, fast forward to the present. over the past 8 years, the jeep has seen very LITTLE driving, and was basically stored for future enjoyment. this past summer, the jeep was brought back to full use. a friend of mine, a mechanic, cleared all the cobwebs, and brought the jeep up to speed. in fact, after some research, i had him install the "Juicebox", TFI upgrade from www.driveajeep.com. start-ups are much better now, but here is the problem. the old idle problems have resurfaced, but only in COLD weather, before the engine has heated up. once the car heats up, the stalling and idle problems seem to minimize, returning to the old 1000-1100rpm idle baseline. i know this rpm level is high for this jeep, but it has always seemed to work and was a decent compromise. i know that there are different cold idle and warm idle "components" in the carbureter. basically, until the car warms up, i have to goose the gas upon slowing down to keep the car from stalling. i think my mechanic friend has given up on this frustrating situation, and despite my TFI upgrade, when the car is cold, in Northeast cold weather, i still stall at any slowdown or stop, unless i coast to the stop, out of gear, with my left foot on the brake and my right foot tapping the gas. i have read various articles, as i mentioned previously, and before i find a mechanic to consider the carter carb fix mentioned here: http://www.jeeptech.com/engine/carter.html or any other ideas i have read here, i wanted to poll the forum.

as i said, the idle curb seems fine, if 1100 rpms is fine, when the car is warm, but stalling is plentiful in cold weather when the vehicle is cold, so do all the classic carter carb problems apply in this situation???? at this point i am not willing to have installed a new Weber, or the nutter bypass. the carter stays, so how best to deal with this specific problem? THANKS

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Unread 10-23-2004, 11:12 AM   #2
el guapo
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2004 TJ Wrangler 
 
Join Date: Oct 2004
Location: Newark, DE
Posts: 286
hey, I'm sort of a newbie jeep owner, and mine seems to be doing the same thing - stalling when cold. it starts fine with one pump on the gas pedal, and high-idles fine, but when you put it in gear and drive away, it will stall at every stop sign/light until it has thoroughly warmed up. i have an '87 with a factory rebuilt carb and new plugs/wires. was just wondering if you ever solved your problem...
Thanks!
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Unread 10-25-2004, 11:59 AM   #3
Tshark299
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1987 YJ Wrangler 
 
Join Date: Mar 2004
Location: Upstate NY
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Well curb idle for the 4.2 with a 5-speed is supposed to be about 650 RPMs... intersting that you're Jeep was like that from day one. I always wondered if these 4.2s had all these problems when they were new... guess I found my answer!

I would say that carter fix would be your best bet if you don't want to get a Weber/.
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Unread 10-25-2004, 12:15 PM   #4
kg6mti
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1987 YJ Wrangler 
 
Join Date: Sep 2004
Location: Sacramento, CA
Posts: 676
My 87' 4.2L had all the same problems. I bought it a little over a year ago; it ran great for a little while but quickly developed all the problems that I have heard others describe. Problems with the idle, dying at stop signs etc.

I am currently in the process of installing the Mopar MPI fuel injection kit. Everything I read has said this kit is the route to go. I will keep you posted as to the results if you are interested.

Thanks!
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Unread 10-25-2004, 12:16 PM   #5
Alex70
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I don't know if my problem is exactly like yours....my Jeep not only will stall up until completely warmed up, but when it's cold and I put it in gear, no matter how high I rev it, even 3,000 rpm, it will still go off, like there's a mysterious force holding it to the ground.....is it a ground for some Jeep Curse....?????
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Unread 10-27-2004, 11:56 AM   #6
amg61
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1990 YJ Wrangler 
 
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FINALLY SOLVED this problem with a cleaning and drilling-out of the venturi idle tubes in the carburetor. that along with an old emission recall i never implemented and everything is good to go !!!!!
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Unread 11-06-2004, 04:14 PM   #7
AV8RsJeep
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Quote:
Originally Posted by agoldtree
FINALLY SOLVED this problem with a cleaning and drilling-out of the venturi idle tubes in the carburetor. that along with an old emission recall i never implemented and everything is good to go !!!!!

I have a 1990 4.2L with the same problem and was wondering what was the recall that you had?
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Unread 11-11-2004, 07:36 PM   #8
bradleyrl
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I also have a 90 model YJ, the best two things that I did to help was the "NUTTER BYPASS" and a HEI distributor from an early 80's Chevy truck with an inline 6. The NUTTER BYPASS I found some where on the web. This is where you disconnect the carb from the computer. This helped a bunch and is cheap, FREE! The HEI distributor was done about a year later. It was out of a Chevy truck with a inline 6 I think it was an 80 model. This was a fairly simple job. I jut had to swap the gear from my oem distributor to the HEI, regap the plugs, and replaced the plug wires. I found the HEI at a local wrecking yard for $10.00. These mods really helped my jeeps performance and won’t break the bank.
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Unread 11-17-2004, 11:43 AM   #9
amg61
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1990 YJ Wrangler 
 
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Posts: 290
Quote:
Originally Posted by AV8RsJeep
I have a 1990 4.2L with the same problem and was wondering what was the recall that you had?

There are a number of recalls, in fact if you check with your local jeep dealer and give him your VIN #, he can look up which ones which were performed. The one i am talking about is recall #589 which affects the emissions system. The PCV shutoff solenoid is removed; the EGR and Decel valve are replaced with new ones, as well as the choke diaphragm, and the emissions harness is replaced. All for free, and this recall, though OLD, is still valid. The other one I tried, 323T which affects the Carb, is no longer valid and will not be performed. But go for recall #589.

But MORE IMPORTANTLY, this did not cure my Cold idle Blues. I had to clean and drill out the Venturi idle tubes as noted in these two links:

consider this carb fix:

http://www.jeeptech.com/engine/carter.html

with these pictures:

http://www.yellowjeep.org/Carb.html

and consider drilling out the venturi idle tubes to 0.040" with a #60 drill bit (by hand).


And, as important, add a TFI ignition upgrade as demonstrated here:

www.driveajeep.com

then do the recall.

or vice versa.
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