engine knock

[ScottWA]

looking for ideas on engine noise(aka knock) I have changes injectors they were done by ddp, I put a fass on the truck. I have changes the fca and had the dealer do an injector kill test. I have an edje juice with attitude air intake and 4 inch mbrp exhaust. I cant seem to track the knock down. I have had oil analyized nothing there fuel filters. The noise is loud and somedays its there and others quiet. Its had the knock since I have owned it and its been about 35k. I have tried fuel additives nothing. So im asking for a sugestion as to any ideas on my knock. the motor has 93k on it now.

 

[04 Diesel Power]

96,000 miles on mine and has knocked since about 30,000 miles, runs great so I just keep driving. I noticed that when I pull long hard trips seem to quiet it down for awhile.

 

[MMeier]

Mine started doing that after I changed injectors... seems only to do it at a certain throttle position with a light load. Will not do it if I'm on it hard, more pronounced when warmer out also, sound like yours?

 

[ScottWA]

actually the engine knocks at an idle mainly. Off idle it goes away or isnt noticiable i guess. really loud like a jackhammer on the block. Sounds like a 99 24 valve

 

[jmorse]

Injection timing can cause a knock . Does the engine knock when run stock, without mods ? Were your old injectors tested to see if one was faulty (on a test stand) ? Poor fuel atimation due to a faulty injector nozzle can cause a knock. Just my . 02.

Jim

 

[ScottWA]

the engine has knocked since new. I sent the injectors to ddp and they changed nozzles and whatever else. With or without mods engine has knocked. I wonder if I modded the crank sensor to change timing if that would help.

 

[Lonestar]

sounds like a faulty injector to me. If you had new nozzles installed, but didn't test the injectors, they would still be bad.

 

[cerberusiam]

Have you tried timing the injection pump?

 

[MMeier]

Mine were tested, 2 were bad. All 6 nozzles were changed. Even with the boxes disconnected, it still knocks.

 

[jjdiesel]

Issue 56, page 38, "Injector Woes"... more than likely has your answer.

 

[Lightman]

Third Gens don't have a timed injection pump all the pump does is pump high pressure fuel





Have you tried timing the injection pump?

 

[cerberusiam]

Third Gens don't have a timed injection pump all the pump does is pump high pressure fuel





Have you tried timing the injection pump?

Ahh, but that is just not so!



The CP-3 is timed to the engine. It runs one-to-one with engine, when the engine is on a compression stroke the pump needs to be on the pressure stroke with one of its 3 pistons. Failure to have it timed correctly creates rattles, knocks, and other strange noises that take many posts and much head scratching to resolve.



Do a search, this has been addressed many times and most times has solved the noise problem. Not saying thats what this is, but, it is a definite rattle/knock that is misleading.

 

[cerberusiam]

Issue 56, page 38, "Injector Woes"... more than likely has your answer.

Hey!! You guys blindly suggesting injector problems PLEASE READ the posts. DDP rebuilt them, they are not generally known for screw ups. Others are posting the same experience.





Sheesh, least little knock and the "bad injector" band wagon gets crowded.





:-laf:-laf

 

[jjdiesel]

Hey!! You guys blindly suggesting injector problems PLEASE READ the posts. DDP rebuilt them, they are not generally known for screw ups. Others are posting the same experience.





Sheesh, least little knock and the "bad injector" band wagon gets crowded.





:-laf:-laf

The article is not all about 'bad' injectors... many times a carboned-up injector is the problem though, not necessarily a bad injector. Many a truck has been worked hard after experiencing these symptoms and the knock goes away.

 

[ScottWA]

is there a post about timing the cp3 or any pointers on how to time it?

 

[sag2]

Do a search because I seem to recall it was posted before, but here is the Readers Digest version.

Remove pump drive gear nut and break gear loose

Mark and rotate pump shaft 30 degrees clockwise

Reinstall nut and fire up. If better stop, if not rotate 30 degrees more.

If the noise is still there, it is not pump rattle

 

[cerberusiam]

The article is not all about 'bad' injectors... many times a carboned-up injector is the problem though, not necessarily a bad injector. Many a truck has been worked hard after experiencing these symptoms and the knock goes away.

Please, please, PLEASE read the posts! :{



He had the injectors rebuilt. Do you think they were still carboned up after that? Mmeir posts the same experience after REPLACING the injectors. We KNOW they can carbon up. We also know putting clean injectors in will get rid of the noise if it is carbon on the tips.

 

[RobertP]

i had my injectors gone through twice and new nozzles installed, and still have the knock. i plan on putting a different set of bigger nozzles on when i get back to full strength.

 

[jjdiesel]

Please, please, PLEASE read the posts! :{



Thanks for the tip! I happened to have my injectors done by ddp as well, had the exact symptoms afterward Thought maybe it would help to reference the article. He did not say the knock started as soon as he had the injectors done... . how long has it been? Do you think they could carbon up later? Oh, by the way, that's rhetorical. Just trying to help, he asked for any suggestions.

 

[cerberusiam]

I happened to have my injectors done by ddp as well, had the exact symptoms afterward Thought maybe it would help to reference the article. He did not say the knock started as soon as he had the injectors done... .

Then I apologize for any semblance of dogging you.



Since you had the same problem did you finally resolve it? What seemed to be the problem?