Stumped! & pulling hair out! - 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 04-03-2011, 01:58 PM   #1
Jeeper
 
_Bubba_'s Avatar
 
Join Date: Mar 2011
Location: Seminole county, Florida
Posts: 23
Stumped! & pulling hair out!

new here to the forums, been looking over them for the last few days, but i have come into some really aggravating trouble, and looking for some guidance. hoping maybe someone else has ran into this before.

Vehicle: 91 YJ 2.5l EFI, 5 spd

started out missing & stumbling real bad @ 2500 rpm, so i replaced the fuel filter, filled up with 93 octane, & added a can of sea foam. runs fine at start up, but when it gets to operating temp (170-190) will start idling @ higher rpm's, sometimes stall out, on its own, or die by pressing throttle pedal, sometimes backfiring when it does die. let it cool down, runs fine again, until it gets up to temp.

this morning, i took a video of it when it got to operating temp.



after you shut it off, or it dies, whichever comes first, it will not start until it cools back down.

after the video, i replaced the MAP sensor, replaced the Coolant Temp Sensor. replaced the coil, coil wire. havent done the intake air temp sensor yet, they put a coolant temp sensor in the box, so i have to run back to the parts store to exchange. got up to operating temp., ran it for 8-10 mins, everything seemed fine. but it still does it. if you do get it to run, it will idle fine, but if you touch the pedal, it just dies, like turning the key off.

codes ( given with the key on-off-on-off-on method):
12- battery (self explanatory)
33-a/c circuit (no a/c)
55- end of diagnostics





i looked at the cat. converter, its a very dark gray on the bottom side, wondering if maybe it plugs up when hot? idk, never had one do this.

thanks for your help.

Bubba

_Bubba_ is offline   Quote Quick Reply
Old 04-03-2011, 02:09 PM   #2
IITYWTMWYBMAB

WF Supporting Member
::WF Administrator::
 
4Jeepn's Avatar
 
Join Date: Apr 2005
Location: Florence, KY
Posts: 10,147
Images: 5
Have you replaced or checked the Throttle position sensor?

__________________
79.96.85.00.01.97.00.97.93.97.95.94
CJ.XJ.CJ. TJ. TJ.ZJ. TJ.TJ. ZJ.ZJ.YJ. XJ
4Jeepn is offline   Quote Quick Reply
Old 04-03-2011, 02:14 PM   #3
Jeeper
 
_Bubba_'s Avatar
 
Join Date: Mar 2011
Location: Seminole county, Florida
Posts: 23
Quote:
Originally Posted by 4Jeepn View Post
Have you replaced or checked the Throttle position sensor?
no i haven't, i assumed (and you know what they say) that because it ran good until it got to temp., it wasnt it. but i will give it a shot too. i have to go return the coolant temp sensor thy gave me in place of the air intake sensor.

thanks for the reply
_Bubba_ is offline   Quote Quick Reply
Old 04-03-2011, 02:17 PM   #4
Jeeper
 
Square_Eyes's Avatar
 
Join Date: Oct 2010
Location: Hayden, Idaho
Posts: 1,428
Had an xj with the 2.5 and it did this same sorta thing, turns out it needed a new fuel pump, might wanna check that too.
__________________
Gettin' Stuck Like A BOSS

Darkproximity- Sometimes I wonder if your jeep was assembled by 8 year olds with nail guns and a lot of caffeine
Square_Eyes is offline   Quote Quick Reply
Old 04-03-2011, 02:52 PM   #5
Jeeper
 
_Bubba_'s Avatar
 
Join Date: Mar 2011
Location: Seminole county, Florida
Posts: 23
Quote:
Originally Posted by Square_Eyes View Post
Had an xj with the 2.5 and it did this same sorta thing, turns out it needed a new fuel pump, might wanna check that too.
already checked, but forgot to mention it. fuel pressure is 37-39 lbs. and fuel pressure regulator is good as well, pressure increases 9 lbs. when its unplugged.

this was actually my first thought, and the first thing i checked. i had a suburban that ran great at idle, or out of gear, but spit, sputtered n popped under load, & after i replaced every electrical part on it, i figured out it was a bad fuel pump, not giving enough pressure.

thanks for the reply though

Bubba
_Bubba_ is offline   Quote Quick Reply
Old 04-03-2011, 04:42 PM   #6
Jeeper
 
_Bubba_'s Avatar
 
Join Date: Mar 2011
Location: Seminole county, Florida
Posts: 23
Update:

changed: Manifold Air Temp Sensor

changed: TPS

will run a little longer, idles flawlessly at operating temp. but will just shut off at random. cranks right back up, idles smooth, has hesitation when you give it some throttle, & stumbles @ 2500, let off the throttle & sometimes it returns to idle, sometimes it cant recover & die, but will restart (didnt restart before when it was up to temp.)

i did find that the o2 sensor has an issue. the harness coming down to it has chafed wires at the pigtail & arcd out on me against the frame when i moved it. i cut the wires back behind the bad spots & taped them (leaving o2 sensor unhooked, & restarted engine. stills idles good at temp., still hesitates when you give some throttle, still stumbles around 2500 rpm, but no check engine light is on with the o2 sensor unplugged.

so now, i have changed the following:

Coil
coil wire
TPS
Manifold Air Temp Sensor
Coolant Temp Sensor
MAP Sensor
Fuel filter

unplugged o2 sensor

filled up with 93 octane
added 1 pint of sea foam


doesnt sound like exhaust is blocked, so i havent removed the cat. converter. but the bottom side is a very dark gray, unlike the top side.

any feedback or suggestions is greatly appreciated.
_Bubba_ is offline   Quote Quick Reply
Old 04-03-2011, 05:03 PM   #7
Jeeper
 
Join Date: Dec 2010
Location: ely, mn
Posts: 207
i had almost the same problem and changed the crank shaft position sensor and it fixed the problem. but it is a fairly expensive part so i would try to avoid guessing on it
abadoobi is offline   Quote Quick Reply
Old 04-03-2011, 06:18 PM   #8
Jeeper
 
Join Date: Jan 2010
Location: Las Cruces, NM
Posts: 2,291
Replace the 02 sensor..
__________________
2013 WRANGLER SPORT 2 DR., V-6 ,AUTO,HARD TOP
(Sold)1994 Jeep Wrangler 2.5L, Bestop top
/w steel half door and slider windows
5 speed, 2.5" lift, 31" tires,rack lights
Garyk is offline   Quote Quick Reply
Old 04-04-2011, 03:19 PM   #9
Jeeper
 
_Bubba_'s Avatar
 
Join Date: Mar 2011
Location: Seminole county, Florida
Posts: 23
Update: Problem resolved!!!!!!

after calling several auto parts stores to discover that while they do have a part number for the pigtail to go to o2 sensor, they do not stock it. dealer only item. call local dealer down in Orlando this morning, only to have them tell me "We do not sell the item, due to fire hazards, BUT, for $790.00, we will sell you the entire wiring harness, which will have the plug you need."

after regaining my composure, i drove 6 miles to one of the local junkyards, went on a search, found a "cherry" cherokee with no motor or trans. (very easy access) for a donor vehicle, clipped off the pigtail, payed 2.00 at the counter, and was on my way.

came home, butt connected together, taped heavily, rerouted, installed new o2 sensor, and once again, she runs like a champ!

electrical has always been my demon, dont like it, & get very, very frustrated dealing with it.

so now, on my way to return all the parts that i didnt need in the first place.

thanks to everyone for their help & suggestions

_Bubba_ is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum 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 email address for yourself.
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

Posting Rules
You may post new threads
You may 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
Pulling my hair out! HIGH SWR on my TJ's bumper mounted CB antenna StinkyMud Communications and Electronics 8 05-14-2011 11:00 AM
Pulling my hair out! HIGH SWR on my TJ's bumper mounted CB antenna StinkyMud Communications and Electronics 10 04-03-2011 05:13 PM
Please help im pulling my hair out!!! snag YJ Tech Forum 7 07-21-2010 03:31 PM
I'm pulling my hair out my_yj YJ General Discussion Forum 2 10-22-2008 11:17 AM
Hair pulling time pennybuy TJ General Discussion Forum 2 01-06-2006 01:25 PM



Download our Mobile App

» Featured Product

All times are GMT -5. The time now is 09:12 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