Notices
JK Electrical, Lighting & Sound Systems Bulletin board forum regarding topics such as stereo head units, CD players, MP3 players, speaker systems, amplifiers, hardmounted GPS devices, computers, headlight upgrades, fog lights, off-road lights, general wiring and anti-theft devices.

Sometimes my Jeep won’t turn over

 
Old 05-22-2019, 05:09 PM
  #1  
JK Newbie
Thread Starter
 
Join Date: May 2019
Location: Rockton, Il
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default Sometimes my Jeep won’t turn over

I drive a 2008 Jeep Wrangler Rubicon and sometimes after it sits, it won’t turn over. For some reason to get it to start you have to push the transmission further into park, hold it there, then turn the key and it starts right up. We’ve taken it to the dealer multiple times and once even paid a lot of money for them to fix it and it’s not been fixed yet. Does anyone know what’s wrong with it and how to fix it?
dakota32580 is offline  
Old 05-22-2019, 05:28 PM
  #2  
JK Jedi Master
 
ronjenx's Avatar
 
Join Date: Feb 2008
Location: Maine
Posts: 12,537
Likes: 0
Received 49 Likes on 45 Posts
Default

When this happens, do you hear a "click" when you turn the key?
ronjenx is offline  
Old 05-22-2019, 06:50 PM
  #3  
JK Newbie
Thread Starter
 
Join Date: May 2019
Location: Rockton, Il
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default

Yeah it kind of tries to turn over but can’t fully do it
dakota32580 is offline  
Old 05-22-2019, 09:27 PM
  #4  
JK Jedi Master
 
ronjenx's Avatar
 
Join Date: Feb 2008
Location: Maine
Posts: 12,537
Likes: 0
Received 49 Likes on 45 Posts
Default

That sounds a lot like the "click- no start" problem quite a few people have had, especially with the early automatic JKs.

Try running a heavy ground wire from the alternator mount bolt to the battery negative terminal. That has solved the problem for a lot of people.
ronjenx is offline  
The following users liked this post:
OnBelay (05-28-2019)
Old 05-23-2019, 08:34 AM
  #5  
JK Jedi
FJOTM Winner
 
resharp001's Avatar
 
Join Date: Jun 2013
Location: Willow Park, TX
Posts: 4,484
Received 249 Likes on 238 Posts
Default

I can't help with the issue, but following along out of curiosity. I was originally thinking it sounded like maybe something in the transmission cable linkage.....like the vehicle is in "P", but you're having to hold the shifter with a little pressure for the computer to recognize it's in "P" in order to crank. Ronjenx, is there some sort of sensor that determines the location of the shifter, or is that all mechanical? This is not an area I've had to explore on my jeep.
resharp001 is offline  
Old 05-23-2019, 02:26 PM
  #6  
JK Jedi Master
 
ronjenx's Avatar
 
Join Date: Feb 2008
Location: Maine
Posts: 12,537
Likes: 0
Received 49 Likes on 45 Posts
Default

Originally Posted by resharp001 View Post
I can't help with the issue, but following along out of curiosity. I was originally thinking it sounded like maybe something in the transmission cable linkage.....like the vehicle is in "P", but you're having to hold the shifter with a little pressure for the computer to recognize it's in "P" in order to crank. Ronjenx, is there some sort of sensor that determines the location of the shifter, or is that all mechanical? This is not an area I've had to explore on my jeep.
With the 42RLE, it's mechanical from the transmission lever to the transmission range sensor, which is inside the transmission, awash in transmission fluid. It's possible the linkage/cable is out of rig, but usually it's a loss of good contact at the range sensor. That loss of good contact can be caused by inadequate engine/transmission grounding.
Here's the sequence of events as I understand it:
The transmission lever is in the Park position.
The transmission range sensor contacts are arranged properly to tell the computer the transmission is in Park.
The key is turned to Start.
The starter relay is allowed to close.
A jolt of electricity tries to go to the starter, but because of inadequate engine/transmission ground connections, some of that jolt finds its way through the transmission range sensor contacts.
The jolt through the sensor contacts causes a loss of continuity to the computer, which brings the start sequence to a halt because the computer no longer sees the transmission as being in Park.
Moving the lever to Neutral, or even further into Park, moves the range sensor contacts enough to reestablish continuity, and the JK is allowed to start.
The addition of a large ground wire from the alternator mount bolt to the battery negative terminal prevents this problem. Adding another one from the engine to the transmission helps, too.

If the OP has the usual click-no start issue, this will help.
ronjenx is offline  
The following 3 users liked this post by ronjenx:
BrandonKTM (06-10-2019), OnBelay (05-28-2019), resharp001 (05-23-2019)
Old 05-23-2019, 04:25 PM
  #7  
JK Jedi
FJOTM Winner
 
resharp001's Avatar
 
Join Date: Jun 2013
Location: Willow Park, TX
Posts: 4,484
Received 249 Likes on 238 Posts
Default

You're a wealth of information Ronjenx! Thank you for that thorough explanation.
resharp001 is offline  
Old 05-28-2019, 01:38 PM
  #8  
JK Super Freak
 
EHarris's Avatar
 
Join Date: Mar 2008
Location: HB, So Cal
Posts: 1,347
Likes: 0
Received 15 Likes on 15 Posts
Default

Originally Posted by resharp001 View Post
You're a wealth of information Ronjenx! Thank you for that thorough explanation.
I owe him lat least 40 beers.
EHarris is offline  
Old 05-28-2019, 07:27 PM
  #9  
JK Freak
 
OnBelay's Avatar
 
Join Date: Oct 2009
Location: Auburn, Alabama
Posts: 592
Received 5 Likes on 4 Posts
Default

Originally Posted by ronjenx View Post
With the 42RLE, it's mechanical from the transmission lever to the transmission range sensor, which is inside the transmission, awash in transmission fluid. It's possible the linkage/cable is out of rig, but usually it's a loss of good contact at the range sensor. That loss of good contact can be caused by inadequate engine/transmission grounding.
Here's the sequence of events as I understand it:
The transmission lever is in the Park position.
The transmission range sensor contacts are arranged properly to tell the computer the transmission is in Park.
The key is turned to Start.
The starter relay is allowed to close.
A jolt of electricity tries to go to the starter, but because of inadequate engine/transmission ground connections, some of that jolt finds its way through the transmission range sensor contacts.
The jolt through the sensor contacts causes a loss of continuity to the computer, which brings the start sequence to a halt because the computer no longer sees the transmission as being in Park.
Moving the lever to Neutral, or even further into Park, moves the range sensor contacts enough to reestablish continuity, and the JK is allowed to start.
The addition of a large ground wire from the alternator mount bolt to the battery negative terminal prevents this problem. Adding another one from the engine to the transmission helps, too.

If the OP has the usual click-no start issue, this will help.
All of this, 100%. The JK grounds are very weak, and the whole JK will benefit from adding additional grounds, and running grounds parallel to existing grounds wherever possible. Oh, and cleaning ground points and applying conductive (NOT DIELECTRIC) grease, etc. You'll amazingly have faster starts, less noise on your HAM/CB radios, and your lights won't dim when you turn the engine over.
OnBelay is offline  

Quick Reply: Sometimes my Jeep won’t turn over


Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: