Injector Knock?
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Junior User
Joined: Jan 2015
Posts: 95
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From: Texas
Injector Knock?
there seems to be an injector knock from #8 injector. I replaced the injector, with a Reman from Full Force and it solved the knock for a couple months then it slowly returned. any idea why? or am I looking at another problem some where else. The knock is not there for the first minute or so that the engine is started on a cold morning but quickly returns as the engine warms up. I also have a DP-Tuner, the knock is the same with and without the tuner.
Fleet Mechanic
Joined: Aug 2006
Posts: 1,465
Likes: 17
From: Jacksonville, FL
Have you re-checked the torque on the hold down bolt since the install? Loose injectors can knock. Some recommend "hot torquing" the injector, which is letting the engine idle up to operating temp with the valve cover off, then re torquing the injector once things are warmed up.
Junior User
Joined: Apr 2015
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the only sure-fire way to rid a 7.3L of the #8 injector cackle is to install single shot injectors with a proper tune. it seems to be an inherit flaw caused by split shot injectors creating a drop in fuel pressure/flow at the end of the fuel manifold in the cylinder head.
Senior User
Joined: Mar 2015
Posts: 320
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A regulated return system can help reduce cackle. I have regulated return on my flatbed and it runs much smoother than the work truck which i deadheaded. Not sure on why it would return but I did and injector swap and with FFD remans and it developed a knock after some miles had accumulated. I do not know the origin of the knock so who knows if it was injectors or something else.
How is fuel pressure?
How is fuel pressure?
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
The knock is most commonly air getting into the fuel because of the poor design of the fuel pickup system. I suggest you search the term "Hutch mod" and consider this mod. Oh... and injectors like to work loose once they've been messed with - popping the top to hot-torque the injector may very well help your case.
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Junior User
Joined: Jan 2015
Posts: 95
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From: Texas
I have rechecked the Torque all was good with that, all injectors were oiling fine or at least seamed to be. I haven't checked fuel pressure yet i do not have a gauge to do so at the moment.
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BigZ97
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
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Dec 17, 2014 07:37 AM
