idling issue - 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 05-01-2014, 07:04 PM   #1
Jeeper
 
Join Date: Jun 2011
Posts: 52
idling issue

I have a pretty stout vibration at idle that smooth up if I press the gas or raise the rpm above 900. It's driving me nuts, especially since it wasn't doing it before. It runs fine otherwise.

It's a used engine I dropped in, it has brand new
Lifters
Plugs
Wire
Rotor Cap and Finger
Injectors
Main and rod bearing
Fuel,air,oil filter
Clutch kit
Tranny
Motor/tranny mounts

I can take the serpentine belt out, doesn't change, no codes stored, balancer doesn't shake at all. Compression are fine, cam is alright.
No loose bolts/nuts, no vacuum leaks. I hooked up my timing light and it showed about 18* of advance at idle, though light hasn't been used in years and once I took it out, it wouldn't work until I popped it open, so I don't want to rely on what it says until I double check with another one.

If you guys can point something I forgot, that would be great.

__________________
/l , [____],
l---L--[]lllllll[]-
()_) ()_)--o--)_)
ilyes is offline   Quote Quick Reply
Old 05-01-2014, 08:34 PM   #2
jokerchief462

WF Supporting Member
 
jokerchief462's Avatar
 
Join Date: Apr 2012
Location: North Las Vegas
Posts: 9,294
Year and engine??? Carb, EFI or throttle body?

The tach is not exactly accurate

18 degrees at idle is a little much thought it should be about 8.

__________________
89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.

AF Jeep Club Tail Number 184
jokerchief462 is offline   Quote Quick Reply
Old 05-01-2014, 08:36 PM   #3
Newb
 
YJ94YJ's Avatar
 
Join Date: Apr 2014
Location: Virginia
Posts: 10
see if your throttle bore and blade are coked up(black carbon deposits on edge of blade and bore walls) you could also check the pintle on the IAC motor
YJ94YJ is offline   Quote Quick Reply
Old 05-01-2014, 10:21 PM   #4
Jeeper
 
Join Date: Aug 2011
Location: north of St.Franisville La.
Posts: 2,006
Send a message via Yahoo to Nubby55
If that don't do it clean the injectors.
__________________
The Government can not give anything to anybody that it does not first take from someone else !
Nubby55 is offline   Quote Quick Reply
Old 05-02-2014, 05:06 AM   #5
Jeeper
 
Join Date: Jun 2011
Posts: 52
It's a 95 2.5L, mpfi. I cleaned the throttle body about a 150 miles ago and swapped in new injectors. I'm gonna clean the IAC and MAP today, hope it helps.

Thanks
__________________
/l , [____],
l---L--[]lllllll[]-
()_) ()_)--o--)_)
ilyes is offline   Quote Quick Reply
Old 05-03-2014, 01:00 PM   #6
Jeeper
 
AllMudd's Avatar
 
Join Date: Apr 2013
Location: SoCal
Posts: 1,437
I swapped in new injectors and the connectors on the wiring were so brittle. I ended up needing to push on the connectors and then super glue them in place so they made a good connection.
AllMudd is offline   Quote Quick Reply
Old 05-03-2014, 01:27 PM   #7
Jeeper
 
0III0forlife's Avatar
 
Join Date: Mar 2012
Location: Ridgway, Pa.
Posts: 3,152
Did you use the flywheel from the donor motor, or the original flywheel?

2.5L are externally balanced. Harmonic balancer on the front and the flywheel on the rear.

Or possibly the flywheel has come loose and is causing the vibration. Everything has to be "clocked" correctly when setting up a 2.5L because of the external balancing.
__________________
'87 YJ, 4.2L built and bored, 8.5" of lift, 8.8 rear, AX15/NP 231, Tom Woods drive shafts, Flat fenders, 12,000LB winch, Custom bumpers, Rattle can paint job. Never completed...
0III0forlife is offline   Quote Quick Reply
Old 05-03-2014, 02:03 PM   #8
Jeeper
 
Join Date: Jun 2011
Posts: 52
Injectors are all spraying fine, I check the connections twice.
I kept the original flywheel, but I took it out to clean it up while replacing the tranny. It is on torque and I still have the same vibration. I just cleaned up a spare throttle body from the old engine and will swap it out monday.
I need to get somebody else timing light to double check my result. If it is my problem, I guess I can only get a new ECM.
__________________
/l , [____],
l---L--[]lllllll[]-
()_) ()_)--o--)_)
ilyes is offline   Quote Quick Reply
Old 05-04-2014, 04:00 PM   #9
Jeeper
 
Join Date: Jun 2011
Posts: 52
Well, I checked the MAP sensor and it is on specs, tried a new one for the heck of it, same result. I also swapped the throttle body, TPS and IAC for a different unit and still the same.
I'm going to get a different timing light to double check the advance.
When I pay attention, I can tell the idle wave up and down slightly. Also, it takes a few engine revolutions to start it, but it may be the way all 2.5L starts.
__________________
/l , [____],
l---L--[]lllllll[]-
()_) ()_)--o--)_)
ilyes is offline   Quote Quick Reply
Old 05-08-2014, 09:14 AM   #10
Jeeper
 
Join Date: Jun 2011
Posts: 52
I just checked the timing with another light, It shows 14 to 16 of advance. It hoovers between the 2 aa the idle goes up and down. I also find I have a partially clogged cat, thanks to that sweet whistle and smell of rotten eggs in the cap when I take the rear window down.

At 8* of advance on the harmonic balancer, the dizzy gear is past number 1 plugs, but not by much. I'm trying to take the dizzy out but the nut won't budge.

__________________
/l , [____],
l---L--[]lllllll[]-
()_) ()_)--o--)_)
ilyes 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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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




» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 01:45 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