88 4.2 issue, help please. - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > 88 4.2 issue, help please.

Light up the holidays with LED lights from JeepHutIntroducing MONSTALINERô UV Permanent DIY Roll On Bed LineRuffstuff Axle Simple Swap Kit!

Reply
Unread 05-18-2011, 05:52 PM   #1
JeepJon15
Registered User
1994 YJ Wrangler 
 
Join Date: Jun 2009
Location: Ohio
Posts: 173
88 4.2 issue, help please.

Hey everyone, thanks for taking the time to read about my issues.

First I wanna list what i have done recently to try to solve my problems.

Nutter
new ignition coil
new spark plugs
new cap/button
new starter
battery connections/wires

Like i mentioned in the title, its an 88 4.2l, after i nuttered the engine it did help, it wouldnt even idle before.
Issue #1
Now i get an unreliable start some days. It will turn all day if i want it to (but dont for the starter's sake) but often times it wont fire up. Now there is never a day where it wont start at all, usually i can wait 5-15 minutes and it will start. This could be a side note, but i had to jump it a few days ago (left the lights on) and for some reason when i fired it up i had a large puff of smoke come out of the carb. Thats the first and only time i've ever seen anything remotely close to smoke come out of there.
Issue #2
This very well could be connected to the first issue, but this is more troublesome, cuz it leaves me stranded in traffic often times. The jeep will cut out in the middle of driving, without warning. It doesnt act like its run out of gas, it just cuts out, leading me to thinking its electrical? After it shuts off sometimes it will immediately start back up other times 5-15 minutes later it will fire up. It will always crank. The starter is only a few months old. I should also mention... when it dies i think i've always be decelerating or taking a turn. I dont remember it ever happening when i've got my foot on the gas very hard or at all. NOTE: this seems to happen only on rainy days, or more often on rainy days for sure.

It idles very weak when first started, i have to let it sit for about 10min before putting it in gear or it will usually stall out (cold start, if its been driven recently its usually good to go). Often times once it does fire up in the morning it goes from a strong 1300 rpm to quickly die off, and it will do that 3 or 4 times before i can get it to stay on. I dont know if this is to be expected from the old carb or what, but i thought i'd throw that in there too. Any help would be awesome

p.s wheni did the nutter i did not twist the orange and purple wires OR take the actual ecu out. Just tonight though, I went out and twisted the wires and reinstalled them. Is it necessary to take the actual ecu unit out to get the full effect of the Nutter?

I know theres a lot of random info there, i hope someone can help make since of it.

Thanks a million
Jon!


Last edited by JeepJon15; 05-18-2011 at 05:55 PM.. Reason: Additional info
JeepJon15 is offline   Reply With Quote Quick reply to this message
Unread 05-18-2011, 06:30 PM   #2
Nickabis
Registered User
1990 YJ Wrangler 
 
Join Date: Jul 2010
Location: Portland, Oregon
Posts: 371
Just saw another post with similar issues you can check out.

http://www.jeepforum.com/forum/f12/4...rible-1215318/

I have a 2.5, so I'm not much help but maybe this post will point you on the right direction
Nickabis is offline   Reply With Quote Quick reply to this message
Unread 05-18-2011, 07:19 PM   #3
mark1305
Member
 
mark1305's Avatar
1989 YJ Wrangler 
 
Join Date: Nov 2010
Location: Merritt Island, Florida
Posts: 200
Check for clogged idle fuel pickup tubes. If looking down the venturis with the motor running you see fuel dribble or squirt in one side and really see it when cracking the throttle, time to clean them out.

Mine was running good, then started dying at stops and idling weird(poorly). Before I found the info on here about idle fuel pickup tubes, I tried the Nutter when I didn't really need to. (But will leave it nuttered).

My misfortune was that when I cleaned the tubes the carb worked great again, but I had pulled the top of the carb off to remove the venturi cluster for cleaning and tore the lip on the accelerator pump plunger when putting it together again. So it idles and pulls great, but stumbles when pushing the gas pedal at first. So there is a rebuild kit on the dining table waiting for me to finish some fix-ups in the cab and exterior.

Search on here for some good tips on cleaning the idle fuel tubes.
mark1305 is offline   Reply With Quote Quick reply to this message
Unread 05-18-2011, 07:24 PM   #4
ChevyBlazerBoy
Registered User
1988 YJ Wrangler 
 
Join Date: Mar 2009
Location: Augusta, Maine
Posts: 116
Also verify your fuel filter has the return line at the highest point and the feed line to the carb at the lowest. Otherwise you will vapor lock it and it will start hard and cause some weird issues.
ChevyBlazerBoy is offline   Reply With Quote Quick reply to this message
Unread 05-18-2011, 08:05 PM   #5
UnFocused
Registered User
1989 YJ Wrangler 
 
Join Date: Sep 2008
Location: Colorado
Posts: 412
Hi Jeepjon, I suspect you have multiple issues non-related. Itís best to do the simple things first because theyíre cheap and fast.

First check for vacuum leaks. Get a can of carb cleaner and spray it around all the vac lines and the base of the carb. Do this slowly (spray in an area and wait) as it takes a little time for the cleaner to get into the engine; if thereís a leak youíll hear a distinct rpm change. Donít forget to spray along the intake manifold as well in case the bolts are loose. Fix whatever you find and then retest everything. This will be a lot easier if you remove the air cleaner assembly - plug any open vac ports caused by the removal.

This link will be valuable to you. In the center column there are instructions on how to tune the carb:

http://home.sprynet.com/~dale02/list.htm

Tune the carb according to the instructions and see if that helps. If that fails, then itís probably time to rebuild the carb. Donít be intimidated, itís very simple. You can get a rebuild kit at any local parts store for about $20 (includes instructions) and get another can of carb cleaner as well, one that has a tube for precise targeting. Thoroughly clean every orifice and channel in the carb, let it soak for a while and blow out with compressed air or your breath. If the carb is filthy inside clean it twice. Reassemble and adjust the settings per the rebuild kit instructions and then tune it per the link above.

If, after that, then thereís probably a non-related electrical issue involving the Ignition Control Module (ICM) located under the wiper fluid reservoir or the ignition switch located on top of the steering column. Letís wait on those two issues until the former have been addressed.
UnFocused is offline   Reply With Quote Quick reply to this message
Unread 05-18-2011, 08:20 PM   #6
timatoe
Registered User
1990 YJ Wrangler 
 
Join Date: Aug 2006
Location: Grass Valley California
Posts: 13,821
I think you have two seperate issues here.

Quote:
Originally Posted by JeepJon15 View Post
This very well could be connected to the first issue, but this is more troublesome, cuz it leaves me stranded in traffic often times. The jeep will cut out in the middle of driving, without warning. It doesnt act like its run out of gas, it just cuts out, leading me to thinking its electrical? After it shuts off sometimes it will immediately start back up other times 5-15 minutes later it will fire up. It will always crank. The starter is only a few months old. I should also mention... when it dies i think i've always be decelerating or taking a turn. I dont remember it ever happening when i've got my foot on the gas very hard or at all. NOTE: this seems to happen only on rainy days, or more often on rainy days for sure.
This sounds like a bad Ignition Control Module.

The rest sounds like clogged venturi tubes.
__________________
Quote:
Originally Posted by George Orwell
We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm.
timatoe is offline   Reply With Quote Quick reply to this message
Unread 05-18-2011, 09:33 PM   #7
faaantastic
Registered User
1989 YJ Wrangler 
 
Join Date: Dec 2009
Location: MA
Posts: 52
I second a faulty ignition module.
Probably clogged tubes as well, might be more than just that. But since cleaning them out only takes five minutes, definitely start there.
I took the whole computer out when I nutter'd mine, but I doubt it makes a difference. Bypassed is bypassed as long as the computer isn't hooked up to anything that it would otherwise send a signal to.
faaantastic is offline   Reply With Quote Quick reply to this message
Unread 05-19-2011, 02:09 PM   #8
JeepJon15
Registered User
1994 YJ Wrangler 
 
Join Date: Jun 2009
Location: Ohio
Posts: 173
Hey guys, thanks so much for all the responses. I've suspected my idle tubes, and looked up the cleaning procedure last night. Its been raining on and off here in ohio all week but i have 3 sunny days coming up tomorrow to sunday, so i'm gunna get those cleaned out and ill check the vacuum lines as suggested.

I'll also verify i have the carb tuned correctly; i wouldnt be suprised if its not exact. My carb says "remanufactured carbs" on it, so maybe the PO did something to it? But i've been wanting to do a cheap rebuild as well... just to be sure its functioning properly. Is this something i could get done in a day if its my first time??

ChevyBlazerBoy: I checked the fuel filter just now... The feed line was slightly higher than the return. I took it off to insure it was free of clogs a couple weeks ago, so i corrected that. Is this really crucial to the car's performance? I never suspected that would cause problems. Anyway we'll see if that produces any improvements. Does it matter how much higher the return is? Or is the point to just let gravity do its job?

Thanks again everyone. I may have time to get some of these things tested tonight, if not ill get back with the results tomorrow afternoon for sure. In the mean time if theres anything else i should check while im in there let me know!

Got my fingers crossed, every suggestion seems do-able
Jon.
JeepJon15 is offline   Reply With Quote Quick reply to this message
Unread 05-19-2011, 02:12 PM   #9
JeepJon15
Registered User
1994 YJ Wrangler 
 
Join Date: Jun 2009
Location: Ohio
Posts: 173
I also should add... Today it didnt rain nearly as much as it has, and i didnt have any starting/stalling problems (besides having to try 2 or 3 times this morning, nothing annoying though). That being said, i went back and twisted my purple and orange lines from my nutter, which i had overlooked when first doing it. I also advanced the timing slightly to about 10 degrees.. it was right on 8. Both things were done last night, then the jeep sat till this morning. Anyway, i wanted to see if you guys thought it was the dryer weather, or those couple things, or maybe a combination of it all?

Last edited by JeepJon15; 05-19-2011 at 02:14 PM.. Reason: Additional info
JeepJon15 is offline   Reply With Quote Quick reply to this message
Unread 05-19-2011, 06:36 PM   #10
JeepJon15
Registered User
1994 YJ Wrangler 
 
Join Date: Jun 2009
Location: Ohio
Posts: 173
Hey guys... back. I got carb cleaner, did some spraying and immediately noticed some leaks. The most noticable is when i spray the middle or bottem, what look to be gaskets. I get an almost immediate increase in rpms, then it eases back down a second later.

I also did a little research and realized i didnt have my dist ported, i had it hooked to the manifold line still. I ran it ported, didnt seem to make a huge difference, i didnt really even have to mess with the timing much i did check it though, its at 10 degrees again. I have yet to take it out for a drive since though.

Anyway, looks like ill be buying that 20$ rebuild kit. Any key tips or advise i would benefit from before doing this for my first time would be awesome. Otherwise ill get back to you guys with my progress or failure lol.

Thanks guys
Jon
JeepJon15 is offline   Reply With Quote Quick reply to this message
Unread 05-19-2011, 07:18 PM   #11
ChevyBlazerBoy
Registered User
1988 YJ Wrangler 
 
Join Date: Mar 2009
Location: Augusta, Maine
Posts: 116
Hey regarding the fuel filter return line up top it is important. I made that mistake myself and had hell of a time starting it once in a while. Especially after i ran it and stopped and wanted to fire it back up again.

Jeep solved this vapor lock problem and put the return line at the top of the fuel filter to let the air out so the gas and vapor is pushed back down to the tank. If the return line is not the highest point above the feed line gas will siphon towards the tank if you let it sit, causing vapor lock which makes her start HARD.
ChevyBlazerBoy is offline   Reply With Quote Quick reply to this message
Unread 05-19-2011, 07:46 PM   #12
4.7stroker
Registered User
1988 YJ Wrangler 
 
Join Date: Apr 2007
Location: Rio Rancho NM
Posts: 4,299
The best setup I found is-----timing to 8*btdc, vacuum advance to manifold vacuum and tune the idle mixture screws for maximum vacuum?

Dwayne
4.7stroker is offline   Reply With Quote Quick reply to this message
Unread 05-19-2011, 08:37 PM   #13
JeepJon15
Registered User
1994 YJ Wrangler 
 
Join Date: Jun 2009
Location: Ohio
Posts: 173
So i drove over here to my brother's house about 5 min away after running it ported. At first i didnt think it to make much of a change. But after simply pulling out of the driveway i noticed a big improvement. It doesnt have the little bucking motion i had going slow or idleing before, and at low rpms and slow acceleration its running much smoother now.

I still have to address the vacuum leaks around the carb this weekend, but i just wanted to report back on that improvement.

I also seem to have an exhaust leak. I plugged my tailpipe with my hand and the jeep didnt stall out. I seem to smell it from the passenger side firewall from the engine, not cabin. Thats just a side note. If anyone knows the key problem areas to check first that'd be helpful.
JeepJon15 is offline   Reply With Quote Quick reply to this message
Unread 05-20-2011, 01:54 PM   #14
JeepJon15
Registered User
1994 YJ Wrangler 
 
Join Date: Jun 2009
Location: Ohio
Posts: 173
Hey guys, after i switched the dist to the ported nipple on the passenger side of the carb, i think i left a vacuum open. Where was the line that was originally hooked up to that nipple on the carb running to? I pulled on it to try and trace it down and it just popped off. I couldnt find what it was hooked up to after that, and it was running fine so i left it. Today it seemed as if i should have plugged something, i had to twist the idle screw pretty much all the way in to get it to idle right.

Anyway, i just got home from work and am preparing to do some testing, and just wanted to get that straightened out first.

Thanks
Jon.
JeepJon15 is offline   Reply With Quote Quick reply to this message
Unread 05-20-2011, 06:37 PM   #15
JeepJon15
Registered User
1994 YJ Wrangler 
 
Join Date: Jun 2009
Location: Ohio
Posts: 173
Sorry, scratch that last post...

I went out to the jeep, popped the hood, only expecting to check for leaks and i got a wild hair up my *** and decided it would be easier if i got rid of all the extra vacuums i didnt need around the carb and whatnot.. I think i got that down okay, or i hope so at least... I did my best to match it up with diagrams i found on this forum.

Anyway, i got to spraying around checking for leaks and... Jesus lol.
I definitely have some leaky lines, most noticeably the pcv set up (not the valve the lines) and the big tube running from the left side of the carb to the charcoal canister. I'm gunna go out and get some new lines for those... but the biggest leak seems to be coming from my exhaust manifold...

I got to looking at it and saw one of the bolts was about a 1/2 inch out! One or two more were loose... and i paid a mechanic to tighten these down less than 2 months ago for fear that i would break them (i didnt check them thoroughly after this was done, so i dont know if he half assed it or they worked their way back out that fast.) . Anyway, i got them tightened as much as i feel comfortable doing here by myself, but it still seems pretty leaky.
Advise on this? I'm expecting ill have to get either a new manifold or gasket or something... i dont know.

The Jeep is running and all, but a combination of the ported dist vacuum producing a natural low idle, and the leaks, i have to have my idle screw almost all the way tightened to stay at 850 rpm. We'll see what improvements come from replacing those few lines that are leaky. (a couple look cracked.)

For anyone who's been following from the beginning... i've had 0 turn offs on the road since i started the thread, its been starting consistently, but i havent seen the kind of RAIN i had the day it shut off on me 5+ times. So we'll see if the problem is corrected or just hiding.

And last but not least, i have not forgotten about cleaning the idle tubes. If i have any daylight left today i will do that. If not, tomorrow it will get done, no question. I understand that will help my idle greatly, i just wanted to see what kind of difference good vacuum lines alone would produce.

Thanks guys, hope someone who can help is still following lol.
Jon


PS! After i removed the various vacuum lines, i plugged 2 ports at the very bottom of the carter. Both on the far right (driver's side) of the carb, like i said, very bottom. Is this correct? Completely wrong? I just want a verification... If i did it wrong i know i can find the info to correct it, so a simple right or wrong would be helpful. I have, what i believe to be, all the lines connected that the diagrams on here show.
JeepJon15 is offline   Reply With Quote Quick reply to this message
Reply

Tags
4.2 , idle , stall , start problems , YJ

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.