I seem to have a knock at mid throttle , no load. I'm not sure being a new 7.3L owner. Maybe a little at Idle, no knock under acceleration. Normal or problem?

2000 7.3L, 78,000 miles, bone stock

Luke

 

OK, let me change that; Once fully warmed up (heat soaked), it sounds like a single cylinder is "knocking". In park, much less; in drive, louder; coasting on the road, nearly gone; under some load, louder again; under full acel. quiteier ( or everything else is too loud to tell. Got any ideas?

 

Sounds like #8 injector Cackle. Do a search for Cackle and see if that is what you have.

 

Definitely sounds like fuel cackle. This subject has been covered many times, in great deal here and on other forums. If you do a fuel cackle search, you chould come up with a ton of information. In short, it is theoretically due to the incompressibility of the fuel in the fuel rail combined with the close firing cycles of cylinders 6 & 8. The common opinion, and Ford's stance, is it will not hurt anything. It can be irritating at times, though.

 

I KNEW you guys would have an idea. I'll do the suggested checking.
Thanks lots,
Luke

 

i have the cackle and i just keep on driving it, it comes and goes, when someone asks me what that noise is i just say that is is my high preformance engine i got and it is supposed to do that, its all that power, what did you think power is supposed to sound like, one of them three cylinder cars. lol

 

Yeah, I've pretty much decided that if I'm asked about it, I'll just look at them like they're stupid and move on.
Luke

 

Doing the Hutch mod and changing out the quick-connects at feed side of the fuel pump will greatly reduce the knock.

 

OK.... When you get time I'd appreciate a bit of explanation of those two procedures and what they do. New guy.
Thanks in advance,
Luke

 

Sorry for the quick answer before, I was heading off to work. Basically you have to remove the fuel tank and modify the fuel pickup like this: http://community.webshots.com/album/32614313yLKyrS
A picture tells a thousand words and this guy was the pioneer.
I also modified my fuel delivery system post filter housing to the cylinder heads with a very small oriface to bleed off the air bubbles that end up in the fuel rails on the cylinder heads. You can see some pics in my gallery.
The threads that I started on the subject are listed below. Some of the pictures that are supposed to be displayed are not there for some reason and I can't edit the original posts to restore them. Sorry.
Part of the reading that I did was on www.texastowncar.com
You must register with them to get in but they don't spam you or sell your email or anything like that. All they are doing is telling us thier experience on trying to fix the cackle and diesel knock. Very informative and well worth the time to read as they are very knowledgable and thorough in thier investigation and work.
All the work that I did made a huge difference. In the end I was able to completly clear up the idle knock with a strong treatment of Lubro Moly Diesel Purge. It cleans the coking and crud from the injector tips and restores performance. At this point I am very pleased with the way my engine sounds and runs. Mileage is still way down there but then again my truck is a 10,000 lb F-550 dually with 4.88 rear end. Waddaya expect?
https://www.ford-trucks.com/forums/s...d.php?t=260173
https://www.ford-trucks.com/forums/s...d.php?t=278697
https://www.ford-trucks.com/forums/s...d.php?t=277571

Hope this all helps. It really does make a difference. Once you do it all and get out on the freeway you'll wonder why you waited so long.

 

Now THAT'S information! I appreciate the trouble you went to.
Luke

 

Let us know how it goes.