I'm stumped here guys, really need help. - 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 > I'm stumped here guys, really need help.

D.i.y. Ford 8.8 tj,xj,yjSavvy Aluminum BumpersSwag Off Road BIG-HIT TJ-YJ Rear Bumper

Reply
Unread 04-23-2013, 07:34 PM   #1
fletcha221
Registered User
1988 YJ Wrangler 
 
Join Date: Apr 2013
Location: doylestown, pa
Posts: 36
I'm stumped here guys, really need help.

Hello all, new member here, great site! I'm working on my friends 88 yj. The thing has no low end in 3rd through 5th. If there is an incline at all in 5th, the thing won't stay above 60. Same deal in 4th and 3rd.

I know these are low hp Motors, but I thought the torque would make it climb like a billy goat. Here is what is driving me insane, she is lean, which explains the crappy low end. However, from all my research, the way this thing is setup, if anything, it should be REALLY rich. Here is the jeep in a nutshell:

Stock motor, exhaust, ignition.
New fuel pump
New holley fuel regulator, set to 5 psi.
New fuel filter.
Weber 34 dgec setup as follows:
-idle jets primary: 55 secondary: 47.5
-run jets: primary: 47.5 secondary 47.5
Idle screw is 1.25 turns from stop
IDLE MIXTURE SCREW IS 4 plus turns OUT!!!!

Timing is set to 10.

The thing starts right up, idles like a charm at 700 rpm. I checked all the vac lines. All the old stuff is gone, the vac advance is hooked up correctly to the distributor , as is the PVC and vent.

I bypassed the Holley thinking it wasnt supplying the needed fuel, runs the same.

The nutter bypass HAS NOT been done. Can the ECU still retard or advance the timing enough to cause this effect???

Im going to step up the primary idle jet to 65 and see if the thing just needs more juice?

Btw, checked for bad gaskets or cracks all around the intake side of the motor....nothing.

Any advice guys????? Please help me? Am I insane? Will this thing simply not climb hills above 35 mph????

fletcha221 is offline   Reply With Quote
Unread 04-23-2013, 09:38 PM   #2
NonRubicon
Registered User
1990 YJ Wrangler 
 
Join Date: Nov 2009
Location: The southern armpit of California
Posts: 2,093
Do the Nutter Bypass before tinkering with anything else. As long as the ECU is in the loop, it will play with the timing and screw things up. Just one more variable you can eliminate.

One thing to keep in mind is that tire size and differential gear ratio will impact the ability of the 4.2 to turn the wheels.
NonRubicon is offline   Reply With Quote
Unread 04-23-2013, 09:39 PM   #3
lestes94
Registered User
1994 YJ Wrangler 
 
Join Date: Aug 2011
Location: Harrison, Arkansas
Posts: 145
Have you considered a possible gearing issue? I know that with mine (4.0L HO/ 5speed) just bumping up to 33's cut my hill climbing power substantially. If your friend has large circumference tires, making it more high geared, he could loose his uphill power. I don't know if that is the case, but I know that that is an issue for many people including myself. Good luck.
__________________
'94 YJ: 4.0L HO fi, 5-speed AX-15, Daystar 1.25" shackles, 17" JK wheels, lined tub, custom paint, Bestop Supertop, etc..
'88 YJ: 4.2L carb, 5-speed, stock everything. Banana-ish yellow. hard top. 26,XXX original miles.
lestes94 is offline   Reply With Quote
Unread 04-23-2013, 10:21 PM   #4
rambo3489
Registered User
1989 YJ Wrangler 
 
Join Date: Feb 2011
Location: Albuquerque, New Mexico
Posts: 1,637
My guess is ignition problems. Or the tire issues talked about. How big of tires and what gears in the Diff? Do you know what your timing is set to? These things can be real dogs unless certain things are taken care of

Sent from my phone because I'm doing something "more important"
__________________
89 YJ.. My first jeep and I won't let it go. ▀||||▀

Current Project: None... I disgust myself.

[URL="http://www.jeepforum.com/forum/f22/my-yj-build-adventures-thread-1356941/"][SIZE="3"][B]BUILDING THE YJ MY WAY[/B][/SIZE][/URL]
rambo3489 is offline   Reply With Quote
Unread 04-23-2013, 10:23 PM   #5
Anticanman
Follow me
 
Anticanman's Avatar
1994 YJ Wrangler 
 
Join Date: Aug 2009
Location: Ripon, California
Posts: 19,229
Need more info. Fill in a profile and lets go from there. Don't care if its yours on paper, you can be the owner on the Internet.
__________________
Luck Favours The Prepared
[SIGPIC][/SIGPIC]
Anticanman is offline   Reply With Quote
Unread 04-24-2013, 06:51 AM   #6
fletcha221
Registered User
1988 YJ Wrangler 
 
Join Date: Apr 2013
Location: doylestown, pa
Posts: 36
Hello all,

To answer a few questions:

1. The drive train is completely stock, trans through the diff. Stock gearing.

2. it DOES have larger tires than stock, I need to check what they are. (I'm at work now) I believe they are BFG mud terrain. The jeep does not have a lift, but the tires do just barely fit in the wells without rubbing. My buddy seems to think they are 30.5x 15x 9's.

3. Timing is set to +10 I believe. Would taking some timing out help?
fletcha221 is offline   Reply With Quote
Unread 04-24-2013, 07:51 AM   #7
yoter
Registered User
1995 YJ Wrangler 
 
Join Date: Feb 2010
Location: lawrenceville, il
Posts: 83
Quote:
Originally Posted by NonRubicon View Post
Do the Nutter Bypass before tinkering with anything else. As long as the ECU is in the loop, it will play with the timing and screw things up. Just one more variable you can eliminate.

One thing to keep in mind is that tire size and differential gear ratio will impact the ability of the 4.2 to turn the wheels.
^ x2
yoter is offline   Reply With Quote
Unread 04-24-2013, 07:54 AM   #8
yoter
Registered User
1995 YJ Wrangler 
 
Join Date: Feb 2010
Location: lawrenceville, il
Posts: 83
Are you timing it with a lite or by ear? Sometimes you can get the timing closer by ear on the older jp's.
yoter is offline   Reply With Quote
Unread 04-24-2013, 08:10 AM   #9
fletcha221
Registered User
1988 YJ Wrangler 
 
Join Date: Apr 2013
Location: doylestown, pa
Posts: 36
I'm timing it by light gun, Most people suggest +8 after the nutter bypass.

Is there any real difference between the motors in the CJ and the YJ? Most of the rich conditions I seen written about are with the Weber 34 DGEC on a CJ. Different head? Compression, etc?
fletcha221 is offline   Reply With Quote
Unread 04-24-2013, 12:01 PM   #10
zeus87gn
Automotive Neurosurgeon
 
zeus87gn's Avatar
1987 YJ Wrangler 
 
Join Date: Sep 2006
Location: Houston, Texas
Posts: 2,410
Something else you will need to check on once you bypass it -

Verify that the dist has the correct mechanical advance for your now bypassed ignition
It should be 15deg or more - just from your description you probably have the original type with only 6deg
Hook the vacuum advance up to manifold vacuum and cap the port on the side of the carb
__________________
Handicapped license plates are not for mentally handicapped people -

"Man has not yet evolved an inch from the primordial slime that spawned him." Mark Blankfield, Jekyll & Hyde... Together again

Holley Carb thread
zeus87gn is offline   Reply With Quote
Unread 04-24-2013, 07:51 PM   #11
fletcha221
Registered User
1988 YJ Wrangler 
 
Join Date: Apr 2013
Location: doylestown, pa
Posts: 36
She's only advanced to 10 degrees, I will move it closer to 14, as most people have.

Hey guys, the tires are 30's. They are the big mud terrain.
fletcha221 is offline   Reply With Quote
Unread 04-26-2013, 10:18 PM   #12
Flajeeper1
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2009
Location: Lakeland, FL
Posts: 726
Your tires are only slightly larger than stock and won't cause the power problems you're experiencing. Try Zeus's advice first and get back with us on the results.
Flajeeper1 is offline   Reply With Quote




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.