Coil test -
LinkBack Thread Tools
post #1 of 2 Old 04-29-2009, 04:30 PM Thread Starter
Registered User
2004 TJ Wrangler 
Join Date: Nov 2008
Location: Bremerton, WA
Posts: 379
Coil test

Is there a testing procedure for the DIS 4.0 coil pack? I've been having an occasional idle miss for the last month or two that finally came to a head today, and the engine is running terribly. No codes except for cyl #4 miss. I've pulled the plugs (Champion 4412) which have less than 15,000 miles on them, and the only thing noticable on #4 is that the insulator is slightly darker than the rest - a possible rich condition?

Since I've never been fully satisfied with these plugs, I will be replacing these in a few minutes with APP985 plugs. When I installed them, they introduced a ping that wasn't present before. They are gapped correctly.

I would like to test the coil if at all possible, but I don't see any obvious testing methods. Lack of wires or individual coils makes pinpoint testing slightly difficult.

P.S. Pulling upstream/downstream O2 sensors didn't help at all, and neither did a full PCM reset and reset of adaptive fuel tables.

incredibull is offline  
Sponsored Links
post #2 of 2 Old 04-29-2009, 07:47 PM Thread Starter
Registered User
2004 TJ Wrangler 
Join Date: Nov 2008
Location: Bremerton, WA
Posts: 379
Could not find APP985 anywhere, so I went with the equivalent Champion 7034 double-platinum. Problem was solved immediately and the engine is running perfectly. If this turns out to be the problem, I must say that I've never had plugs go bad so quickly. I don't know what the problem could have been with the Champion 4412s.
incredibull is offline  

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


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.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
4.2 coil test grimjeeperyj14 YJ Wrangler Technical Forum 1 09-26-2009 11:09 AM
How do I test a ign coil wire 91-2.5l dynamic098 YJ Wrangler Technical Forum 6 03-03-2009 06:33 PM
Compression Test on Newer TJs with coil pack 02tjsport TJ Wrangler Technical Forum 11 10-04-2008 11:43 AM
Test a coil? drmaxdc YJ Wrangler Technical Forum 1 08-09-2004 12:29 AM

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 On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome