1988 YJ 4.2L I6 Very rough idle and no power - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 11-28-2010, 03:42 AM   #1
Newb
 
Join Date: Nov 2010
Location: TUSCALOOSA ALABAMA ROLL TIDE!!!
Posts: 11
Exclamation 1988 YJ 4.2L I6 Very rough idle and no power

I have replaced all the lines after my dad removed them all. I probably dont have them in the correct locations. Need a diagram very bad.
When it starts it will idle but very rough and smokes pretty bad white smoke. when you press the eccelerator it is very sluggish.

Has new accel plug wires 7mm, new distrib cap, new plugs, new vac lines, k&n filter, Flowmaster, new alt, new radiator, new belts, new control module, new batt, new starter.

b.rainey01 is offline   Quote
Old 11-28-2010, 09:55 AM   #2
Member
 
Join Date: Aug 2010
Location: 4wheel heaven
Posts: 211
check your timing if its off at all then it does that

yjforlife is offline   Quote
Old 11-28-2010, 09:21 PM   #3
Jeeper
 
Join Date: Nov 2010
Posts: 16
Images: 8
How did it run before working on it ?
mholloway1809 is offline   Quote
Old 11-29-2010, 10:20 AM   #4
Newb
 
Join Date: Nov 2010
Location: TUSCALOOSA ALABAMA ROLL TIDE!!!
Posts: 11
1988 YJ 4.2L I6 Very rough idle and no power

It had sat up for 8 years in our shop. Put all the new parts on and got it running. It ran smoked but had great response with no hesitation. It sounded great except for a little spuddering like the plugs needed replaced. Then it got hard to start and would run real rough. Part of it may be that the vac lines aren't all correct. The diagrams I've found mostly suck or they are missing lines that I have.
It's the 4.2 I6 factory air cleaner with K&N filter runs like crap with the filter on or off.

Forgot to mention i replaced the rotor button also.
b.rainey01 is offline   Quote
Old 12-01-2010, 04:49 PM   #5
Jeeper
 
Join Date: Nov 2010
Posts: 16
Images: 8
Set the engine to the top dead center mark on the crankshaft and check the postion on the #1 spark plug wire, If its off by half rotate the engine 1 more revolution and check that the number one plug wire is in the correct position.
then with the distributor cap removed turn the engine over and verify which way the rotor turns and insure the plug wires are connected in the proper order in the correct direction.
Then start the engine and check and adjust the ingnition timing as needed, remember to remove the vac hose from the distributor before checking.
__________________
88 YJ, 4.2 5spd, Hardtop, 6" Skyjacker Monoleaf, 33's on alloy, RockCrawler Bumpers, Tube fenders, Full wrap body armour, 4.88's, SYE W/CV.
mholloway1809 is offline   Quote
Old 12-01-2010, 08:57 PM   #6
Jeeper
 
Join Date: Sep 2009
Location: Colonial Heights Va.
Posts: 87
welcome to the fourm you might want to try a nutter bypass
drox is offline   Quote
Old 12-02-2010, 10:54 AM   #7
Newb
 
Join Date: Nov 2010
Location: TUSCALOOSA ALABAMA ROLL TIDE!!!
Posts: 11
Thank you for the response very much

I have not been able to try your suggestions yet. But, I will this weekend and let you know how it went. Again, thank you very much... If that works I owe you big time!
b.rainey01 is offline   Quote
Old 01-10-2011, 04:04 AM   #8
Newb
 
Join Date: Nov 2010
Location: TUSCALOOSA ALABAMA ROLL TIDE!!!
Posts: 11
Update

I'm working on both posts. I have started the Nutter Bypass. I only have the purple to purp and orange to orange and back in the loom. I need a good diagram on the vacuum lines post nutter. I've seen a few diagrams, one of them shows a line to the 4wd system off the manifold vac. Is this correct? Here is a pic of the one I found to be the best one so far. Which one of the two should I use for my 88 YJ 4.2 L I6 with carter bbd?
Attached Thumbnails
Click image for larger version

Name:	Nutter Diagram Best 1.jpg
Views:	404
Size:	33.7 KB
ID:	34490   Click image for larger version

Name:	Nutter Best 2.jpg
Views:	367
Size:	41.0 KB
ID:	34491  

b.rainey01 is offline   Quote
Old 01-10-2011, 04:36 AM   #9
Deaky

WF Supporting Member
 
Fweaky's Avatar
 
Join Date: Aug 2009
Location: Central Virginia
Posts: 2,204
Images: 18
Tie the 4wd vacuum line into the manifold vacuum like the top picture.
__________________
Nothing is foolproof to a sufficiently talented fool.
Fweaky is offline   Quote
Old 01-10-2011, 10:28 AM   #10
Newb
 
Join Date: Nov 2010
Location: TUSCALOOSA ALABAMA ROLL TIDE!!!
Posts: 11
Thank you Fweaky. I'm trying to see what all I can rip out of this thing now. there is a rat nest of vac lines. I replaced all of them with new lines. But, I'm dying to finish the Nutter and clean house under the hood.
b.rainey01 is offline   Quote
Old 01-11-2011, 01:48 AM   #11
Jeeper
 
90YJinPC's Avatar
 
Join Date: Feb 2010
Location: Panama City, Fl
Posts: 137
Sound like your carb. idle ports are plugged. Very common with stock carbs. The white smoke is a concern. Check your water and oil and make sure there is no mix between the two.
90YJinPC is offline   Quote
Old 01-15-2011, 08:38 PM   #12
Newb
 
Join Date: Nov 2010
Location: TUSCALOOSA ALABAMA ROLL TIDE!!!
Posts: 11
Exclamation Update 1-15-2011

Ok, today
1. Finished the wiring side of the Nutter Bypass and cleaned up harness real good.

2. Ripped out all the vacuum lines and used the above diagram keeping the canister.


Result = It starts a little easier but runs like crap same as before.

Concerns =

1. I have no vac lines from carb going or manifold going to 4x4 system.

2. There is a round ball looking object with 2 vac lines running out of it under the battery tray what is this? Can I rip it out?

3. I know I have to set the timing but I've never done it before.
Attached Thumbnails
Click image for larger version

Name:	DSCN0506.jpg
Views:	124
Size:	220.4 KB
ID:	34987  
b.rainey01 is offline   Quote
Old 01-16-2011, 02:23 AM   #13
Jeeper
 
90YJinPC's Avatar
 
Join Date: Feb 2010
Location: Panama City, Fl
Posts: 137
That is a vacuum resivor under the battery. Looks like it has been disconnected by your photo. Here is a site that may help answer some questions.

Table of Contents

More info that may help.

To move the fork, Chrysler decided to use a vacuum powered motor. A vacuum source line is run from somewhere on the engine (the location varies and can come from the brake booster, the manifold, etc) to a vacuum switch on the transfer case. When 4wd is selected, the switch sends the vacuum along several lines to the shift motor located on the front axle. The vacuum pressure is applied to a diaphragm inside the motor, thus sucking it one way or the other, depending on whether the axle is engaging or disengaging. The diaphragm is connected to the end of the shaft that the shift fork is attached to, thus moving the fork along with it. The problem with this system generally lies in the vacuum lines themselves. Over time, the lines harden and crack and dry rot. The older the vehicle, the more likely this will happen. As cracks form, air leaks soon follow, lowering the amount of vacuum pressure that is in the lines. After a certain point, there is no longer enough pressure to move the diaphragm, thus causing leaving the fork motionless. More often then not this is problem with the system. Included below is a diagram of the 4wd vacuum system.
Attached Thumbnails
Click image for larger version

Name:	Vacuum_diagram1.jpg
Views:	188
Size:	27.3 KB
ID:	35002  

90YJinPC is offline   Quote
Reply

Tags
1988 yj , 88 yj , vac lines , vacuum lines

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
rough idle dmwilson01 YJ Tech Forum 4 12-12-2010 11:16 PM
Recently developed rough idle and stall '87 YJ w/i6 Hardwater Kiter YJ Tech Forum 0 08-24-2010 09:53 PM
89 YJ 4.2L idle is rough, need your ideas :) jeepfan123 YJ Tech Forum 10 04-25-2010 04:48 PM
Strange Rough Idle djl7780 TJ Tech Forum 4 04-15-2010 08:08 PM
Runing rough, idle rough, cylinder #4 misfire spdrcrpete TJ General Discussion Forum 13 06-02-2008 02:32 PM



Download our Mobile App

» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 04:22 AM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC