73 TD intermittent 'clack' and some power loss - Diesel Forum - TheDieselStop.com
7.3L IDI Diesels (Not Power Strokes) Technical discussion of topics related to vehicles powered by the 7.3 Liter In-Direct Injection Navistar engines.

LinkBack Thread Tools Display Modes
post #1 of 3 (permalink) Old 10-17-2019, 12:32 PM Thread Starter
Junior Member
Join Date: Oct 2019
Posts: 1
My Photos: (0)
Feedback Score: 0 reviews
73 TD intermittent 'clack' and some power loss

I have a '94 7.3 vin K turbo diesel. A while back it started losing some power on hills. As in I'd put it to the floor and get nothing sometimes, just plug along. Other times it would respond as expected and power up the grades. Two days ago it started sounding louder, both at idle and working, same general sound just louder. Yesterday it started the 'clacking' while at idle and power, jumping from normal 'quiet' operation to being really loud. It happened for various durations at various RPMs. For the last couple miles getting home it also started surging and coughing like a plugged fuel filter would do. Not bad or constant but noticeable. Until then it was performing fine just loud. I've been having an issue with bad fuel and have changed the filter multiple times in the last few months, including yesterday after the issues just to see. There was no change. The only other thing I've done is top off the oil. I'm not what you'd call a mechanic. I know how to do what I know how to do and am picking up more all the time. Not sure if this is something I'd want to tackle but need to figure out what the issue is first. Any help would be appreciated.
mainemtnmn is offline  
Sponsored Links
post #2 of 3 (permalink) Old 10-18-2019, 08:34 PM
Senior Member
Join Date: Nov 2008
Location: Salina, Kansas
Posts: 1,566
My Photos: (0)
Feedback Score: 0 reviews
It sounds like you're describing a fuel knock. Look at the top of the injectors for wet spots, that is where the most common place is for air intrusion is. That knock you describe is from the injectors getting a slug of air, or lack of fuel. From there it is anybody's guess. Air comes from many places and will leak in where fuel won't leak out. Usually the bonnets on top of the injectors (which are sealed with O-rings) will start leaking, and the knock is the first sign. After a while, it won't want to start.

1993 F-350 crew cab non-turbo 5 speed transmission
35 years a mechanic on large stationary engines natural gas and diesel fired, and other industrial equipment.
oldrebuiltdodge is offline  
post #3 of 3 (permalink) Old 10-22-2019, 08:40 PM
Join Date: May 2017
Location: Huntsville, AR
Posts: 56
My Photos: (0)
Feedback Score: 0 reviews
mine was doing that and it was a injector going out. changed it and worked and sound normal after that. the way i tested it was to have it running and break loose each line to the injector tell you find one that dont make a change in the sound of the truck and thats your bad one. not saying this is your problem just giving you something to try.

90 f350 2wd 7.3idi non T 5speed
DevilDog6154 is offline  
Sponsored Links

  Diesel Forum - TheDieselStop.com > Ford Diesels > 7.3L IDI Diesels (Not Power Strokes)

Quick Reply

Register Now

In order to be able to post messages on the Diesel Forum - TheDieselStop.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:


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
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