Cylinder 5 Misfire - JeepForum.com
 
LinkBack Thread Tools
post #1 of 4 Old 12-06-2012, 02:44 PM Thread Starter
crazyjz
Registered User
1997 TJ Wrangler 
 
Join Date: Jul 2011
Location: Westminster
Posts: 7
Cylinder 5 Misfire

I have a misfire on Cylinder 5 of my 97 jeep wrangler 4.0L Straight 6. I have replaced the distributor cap and rotor, i have replaced and gaped my sparkplugs i have tested the plug wires, i have done electrical testing on the wiring leading up to the fuel injectors, i even switched the fuel injectors from 5 to 3 and 3 to 5 but still i am getting a misfire on cylinder 5. my lack of knowledge and experience has me stuck, i dont know what else to do, other than take it to a mechanic, but i really would rather learn something new to try my self. does anybody have suggestions for a young new (jeeper?)
Thanks, Justin ZJ

crazyjz is offline  
Sponsored Links
Advertisement
 
post #2 of 4 Old 12-06-2012, 07:45 PM
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
2010 JK Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 6,880
Quote:
Originally Posted by crazyjz View Post
I have a misfire on Cylinder 5 of my 97 jeep wrangler 4.0L Straight 6. I have replaced the distributor cap and rotor, i have replaced and gaped my sparkplugs i have tested the plug wires, i have done electrical testing on the wiring leading up to the fuel injectors, i even switched the fuel injectors from 5 to 3 and 3 to 5 but still i am getting a misfire on cylinder 5. my lack of knowledge and experience has me stuck, i dont know what else to do, other than take it to a mechanic, but i really would rather learn something new to try my self. does anybody have suggestions for a young new (jeeper?)
Thanks, Justin ZJ
The ASD relay provides power to all the injectors on a dark green wire with a black stripe. The PCM provides a separate ground for the injectors to fire them. #5 probably isn't getting that ground. It should be a pink wire with a black stripe. Follow it back to where it goes into a splice...maybe the wire got broken.

It goes eventually goes back to pin B6 of the PCM plug (The white plug)

Do you know what was good about the good old days? I wasn't good, And I wasn't old!

Senators and Congressman should wear uniforms like NASCAR drivers so we could identify their corporate sponsors....
laybackman is offline  
post #3 of 4 Old 12-07-2012, 10:36 AM Thread Starter
crazyjz
Registered User
1997 TJ Wrangler 
 
Join Date: Jul 2011
Location: Westminster
Posts: 7
Well yesterday I decided to try and re-replace just the number 5 spark plug, and now it is running like new.. I never thought to check the very first thing I replaced. Thank you laybackman for your reply I still will take a look at those wires, am just starting to learn about the detailed workings of my jeep and it will be nice to know about grounds and the like.
Thank you again,
Justin ZJ
crazyjz is offline  
post #4 of 4 Old 12-07-2012, 01:18 PM
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
2010 JK Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 6,880
Quote:
Originally Posted by crazyjz View Post
Well yesterday I decided to try and re-replace just the number 5 spark plug, and now it is running like new.. I never thought to check the very first thing I replaced. Thank you laybackman for your reply I still will take a look at those wires, am just starting to learn about the detailed workings of my jeep and it will be nice to know about grounds and the like.
Thank you again,
Justin ZJ
Ok that is good to hear! But, here is how I think. Now that you replaced #5 cylinder spark plug with another new spark plug, was the plug NG or you tugging on wires and generally pushing stuff around that 'fixed' this problem?

I would get a multimeter and check the plug out.
Set it at the lowest Ohm setting and then check for resistance between the electrode and the sprak plug's threaded body. ANY resistance means the plug is NG.

Do you know what was good about the good old days? I wasn't good, And I wasn't old!

Senators and Congressman should wear uniforms like NASCAR drivers so we could identify their corporate sponsors....
laybackman is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com 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 e-mail address for yourself.



Email Address:
OR

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.




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



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