N14 cummins miss at idle - Diesel Truck Forum - TheDieselGarage.com
Thread Details Posted by jsbiohazard, this thread has received 1 replies and been viewed 193 times.

LinkBack Thread Tools Display Modes
post #1 of 2 (permalink) Old 02-21-2020, 08:26 PM Thread Starter
Junior Member
Join Date: Feb 2020
Posts: 1
Points: 230
Thanks: 0
Thanked 0 Times in 0 Posts
N14 cummins miss at idle

I am chasing a miss at idle again with my cummins n14. It is in a 98 fld120 425hp It will miss and sound like the motor is kind of loping after it warms up for a few minutes. It is pulling real good but sounds bad at idle. I have replaced the ecm, injector harness, and 5 injectors in the last 3 months. The 6th injector is 1 year old. When I unplug each injector, they all seem to make a difference in idle but I know that this is not the correct method since the Insite program isolates the amount of fuel going to each injector when doing the cutout test. I think that maybe I have an injector that is over fueling possible and causing the ecm to compensate fuel supply to other injectors but I dont know how to isolate this . If I set the idle up to 1000rpm it will run a little rough for about 3-4 seconds and then clear up and run smooth. I have been reading this forum for years and finding solutions from everyone's input but this is my first thread because I cant find where someone else has had this particular issue. Thanks in advance for any help
jsbiohazard is offline  
Sponsored Links
post #2 of 2 (permalink) Old 03-15-2020, 10:56 AM
Junior Member
Join Date: Feb 2013
Location: Nebraska
Posts: 188
Points: 21,403
Thanks: 48
Thanked 67 Times in 55 Posts
Have you made basic fuel checks like air in fuel, fuel restriction and rail pressure? Were the injectors you put in new or recon? Recon's don't exactly have a stellar reputation. Maybe try checking exhaust temps to isolate a cylinder. You're not wrong in suspecting one injector could be over fueling at idle. You didn't say if you've tried a cylinder balance test with insite. This can be a difficult problem to find.
techmech is offline  

Quick Reply

Register Now

In order to be able to post messages on the Diesel Truck Forum - TheDieselGarage.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:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

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 On
Pingbacks are On
Refbacks are On

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