88 yj running rough - 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 yj running rough

Want to be able to SEE? DOT Approved Headlights for under We have FLASHLIGHTS! Great for your Emergency bag!Flowmaster Overstock: Special Holiday Pricing!!!!

Reply
Unread 04-26-2013, 02:44 PM   #1
sloopie
Registered User
1988 YJ Wrangler 
 
Join Date: Feb 2013
Location: lamar, MO
Posts: 40
88 yj running rough

I have an 88 yj with 4.2 and Weber 32/36 carb. It has the nutter bypass. Under load it is missing and has got progressively worse in the past few weeks. It used to happen at higher rpms. Now it does it at any rpm. I put née cap and rotor plugs and wires. Along with a new fuel filter. It has a new coil also. Could it be the original exhaust plugged up or off time? Any help appreciated.

sloopie is offline   Reply With Quote Quick reply to this message
Unread 04-27-2013, 11:23 AM   #2
sloopie
Registered User
1988 YJ Wrangler 
 
Join Date: Feb 2013
Location: lamar, MO
Posts: 40
No?
sloopie is offline   Reply With Quote Quick reply to this message
Unread 04-27-2013, 12:35 PM   #3
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 15,633
It is only missing under load?
Que89YJ is online now   Reply With Quote Quick reply to this message
Unread 04-27-2013, 01:45 PM   #4
Old4X
Registered User
1990 CJ7 
 
Join Date: Nov 2008
Location: Ga
Posts: 5,152
Check for vacuum leaks, especially under the carb and at the intake to head mount.
__________________
418 miles on 19 gallons of gas. Can't beat the BBD !
Old4X is offline   Reply With Quote Quick reply to this message
Unread 04-27-2013, 02:44 PM   #5
sloopie
Registered User
1988 YJ Wrangler 
 
Join Date: Feb 2013
Location: lamar, MO
Posts: 40
Yes only under load. I'll check for leaks with some carb cleaner now.
sloopie is offline   Reply With Quote Quick reply to this message
Unread 05-09-2013, 10:02 PM   #6
sloopie
Registered User
1988 YJ Wrangler 
 
Join Date: Feb 2013
Location: lamar, MO
Posts: 40
No vacuum leaks. Maybe my ICM?
sloopie is offline   Reply With Quote Quick reply to this message
Unread 05-09-2013, 11:12 PM   #7
Old4X
Registered User
1990 CJ7 
 
Join Date: Nov 2008
Location: Ga
Posts: 5,152
What is your plug gap?

Are you using the Team Rush upgrade?

Skipping under load can indicate high voltage breakdown if vacuum is OK. Also, have you looked at the timing marks (with timing light) as you increase RPMs? Is it smooth or jumpy?

Ported or manifold vacuum for vac advance?
__________________
418 miles on 19 gallons of gas. Can't beat the BBD !
Old4X is offline   Reply With Quote Quick reply to this message
Unread 05-09-2013, 11:31 PM   #8
JeepingJustin
Registered User
1990 YJ Wrangler 
 
Join Date: Mar 2013
Location: Sylvia, Kansas
Posts: 100
Quote:
Originally Posted by old4x View Post
what is your plug gap?

Are you using the team rush upgrade?

Skipping under load can indicate high voltage breakdown if vacuum is ok. Also, have you looked at the timing marks (with timing light) as you increase rpms? Is it smooth or jumpy?

Ported or manifold vacuum for vac advance?
x2
JeepingJustin is offline   Reply With Quote Quick reply to this message
Unread 05-10-2013, 07:57 AM   #9
sloopie
Registered User
1988 YJ Wrangler 
 
Join Date: Feb 2013
Location: lamar, MO
Posts: 40
Vacuum advance is ported. Have not checked timing and no team rush.
sloopie is offline   Reply With Quote Quick reply to this message
Unread 05-10-2013, 10:29 AM   #10
Old4X
Registered User
1990 CJ7 
 
Join Date: Nov 2008
Location: Ga
Posts: 5,152
Re tune it for manifold vacuum and see if the problem is still there.

You can not run over .035 plug gap without upgrading wires, cap and rotor.
__________________
418 miles on 19 gallons of gas. Can't beat the BBD !
Old4X is offline   Reply With Quote Quick reply to this message
Unread 05-10-2013, 12:12 PM   #11
dtn8tr
Web Wheeler
 
dtn8tr's Avatar
1997 TJ Wrangler 
 
Join Date: Mar 2010
Location: Waconia, Minnesota
Posts: 1,276
After all is said and done, upgrade your cap, rotor and wires like Old4x said. That original 18,000volt coil sux. I noticed an immediate improvement when I changed all that out.
__________________
1997 TJ, 4" ProComp, 33x12.5x15 Firestone Destination MT, JKS Quicker disconnects
sold-1988 YJ, 4.2L, 2.5" OME, .75" boomerangs, 33x12.5x15 Cooper Discoverers, Herc'd,Nuttered, TeamRush'd
2001 WJ stock DD, 4.0l, Select-Trac

Most good stories start out "Y'all ain't gonna believe this ****...."
dtn8tr is offline   Reply With Quote Quick reply to this message
Unread 05-10-2013, 03:08 PM   #12
sloopie
Registered User
1988 YJ Wrangler 
 
Join Date: Feb 2013
Location: lamar, MO
Posts: 40
I've got new cap, rotor, plugs, coil and wires. Also new fuel pump and filter. Tried rejetting the Weber 32/36 but didn't help. My plug gap is right at 30
sloopie is offline   Reply With Quote Quick reply to this message
Unread 05-10-2013, 07:07 PM   #13
Old4X
Registered User
1990 CJ7 
 
Join Date: Nov 2008
Location: Ga
Posts: 5,152
Quote:
Originally Posted by sloopie View Post
I've got new cap, rotor, plugs, coil and wires. Also new fuel pump and filter. Tried rejetting the Weber 32/36 but didn't help. My plug gap is right at 30

I have gotten more junk, bad out of the box parts in the last 3 years than all of the previous 40. Make absolutelu sure yod don't have a bad plug or wire (or two).
__________________
418 miles on 19 gallons of gas. Can't beat the BBD !
Old4X is offline   Reply With Quote Quick reply to this message
Unread 05-10-2013, 07:29 PM   #14
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 15,633
You need to check the timing and see if your timing chain is loose. Do you hear any slap on the timing cover?
Que89YJ is online now   Reply With Quote Quick reply to this message
Unread 05-11-2013, 08:38 PM   #15
NonRubicon
Registered User
1990 YJ Wrangler 
 
Join Date: Nov 2009
Location: The southern armpit of California
Posts: 2,098
Plug gap specs for the 4.2L range from 0.033 to 0.038 for the stock coil. The gap on your plugs is a bit too small.
NonRubicon is offline   Reply With Quote Quick reply to this message
Reply

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






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.