mokboyd

I have an 07 5.9, at hot idle has a random almost fuel knock,when you rev up engine this goes away.Fuel mileage is very good no smoke ,idles smooth.Idle is louder than other new dodges I have listen too.When cold engine is very quiet,only does this when hot,2500 miles and no mods.Dealership put on computer you know the answer,checks ok!.any ideas would help alot,I am switching over from d-maxes.

MikeyB

Could be carbon build up on one of the injectors. Try running a heavy dose of diesel injector cleaner (Howes, Power Service, Redline, etc) and see if it goes away.

MikeyB

NCYZ1V

mine does the same thing....the dealer said their was tsb. but it did not fix the knock.
Then they sayed.. valve ajustment..(not covered) 400.oo they BE crazy!!!
I will ajust them one day for FREE!

Hairy1

If you swithed from a D-Max....your just hearing a different sound from the Cummins engine......My guess ...no problem

NCYZ1V

I came over from FORD but my buddy has te same truck (he sold me on it) his is much quieter...altho we found out his has 750 hr on it with 30k miles mine I GOT USED has 1400hr. on it with 30k miles.

Chubby

Mine had the same problem but it would come and go. It would get louder and then sometimes go away. 6 new injectors took care of it.

4x4 Neal

not sure if this will help on the 07, but it did on my 96 cumming when i had it, i was told to change the fuel filter, and it fixed the problem, and months latter the same thing, and change it again and the tapping went away. hope this helps.

mokboyd

Thanks for all the idea's I put in a quart of ps. and changed the fuel filter ,everything is still the same.Sometimes when truck is hot it does not bust right off when you turn on the key,which is not normal for these trucks.I am going to check with a different dealership in Wichita Falls tomorrow, they supposedly have a good cummins mech.Thanks again.

deerefarm06

I thouhgt my truck was the only one that did this!! Ive got 28K on her and it still does it, I just consider it a normal thing now...

Spooler

I would say this no doubt is a carbon knock. 1400hrs with 30,000 miles means a ton of idling time. Go hook up to the heaviest thing you can find and drag it around. Keep the EGT's up to 1000 for a while. This is the fastest way that I have found to clean mine out. I don't use PS or Howes Meaner Cleaner anymore. No need to. However, the Howes's Meaner cleaner did work.

00Dog

Running some bio-diesel with the diesel #2 made mine soooooo much quieter. It got rid of a tapping noise too.

Bookmaker

I got the same result adding 2 stroke oil.

05 CTD2500

I've got this same tapping sound too... about 800 hrs and 21,000 mi so a lot of idling on mine also, been running Power Service through every tank for the last probably 4-5. I hope its as easy as keeping the EGT's up for awhile.

gtstrkd

Several people have told me to add a bottle of sea foam when changing the fuel filter to help with carbon build up and injector noises.

mokboyd

Thanks everyone for help,I have an app. thurs in altus,ok.They have a good cummins tech,thier my truck only has 65 hours and 2800 miles on tap has been since day one ,I had 2 6.0's bought back before going to d-max,have always likd dodges,now especially mega-cabs,just do not like problems,d-mxes were trouble free as with the other 5 dodges I had before kiddos.
thanks again