engine knock, worse when put into gear??

[Bailman]

I have a knock in the engine compartment, really notice it more when truck is put into gear- but it will also knock while in neutral or park. I can really hear it well when I am at a drive through- noise bounces off the wall real well. Any suggestions? If I go to the dealer, will trouble codes come up if there is no light on? I would like to go in there with a thought as to the problem. Thanks- by the way- 2003 quad 4x4, so w/47re, stock except for AFE, BD X monitor and 4" exhaust.

 

[RACE427]

Diesel Knock

Is your knock a normal diesel knock or do you suspect a connecting rod bearing knock? Most diesels will sound louder when you put the auto trans, i equipped, into gear. Diesels are also louder on cold winter days when first started after a cold soak.

 

[Scrappy]

check the codes and are there any other symptoms? White smoke @ startup?

 

[nickleinonen]

sounds like an injector imbalance issue... some here have had similar problems... there is one thread with sound clips too... if you search you can find them. . those that have had the imbalance noticed the slight knocking would increase when you went into gear [slushbox trannies] as the engine speed drooped a bit and the ecm increased fueling to maintain idle speeds...

 

[B.G. Smith]

If there is no noticable miss or smoke from the engine it could be the flex plate. I have read where injector malfunctions can cause knock in the 3rd gen. trucks. bg

 

[betterthanstock]

I have a knock in the engine compartment, really notice it more when truck is put into gear- but it will also knock while in neutral or park. I can really hear it well when I am at a drive through- noise bounces off the wall real well. Any suggestions? If I go to the dealer, will trouble codes come up if there is no light on? I would like to go in there with a thought as to the problem. Thanks- by the way- 2003 quad 4x4, so w/47re, stock except for AFE, BD X monitor and 4" exhaust.

Mine starting doing the same about 1000 miles ago, noticeable at very light throttle, up to about 14-1500 rpm. Goes away under heavy throttle.

It's likely the spool (shuttle) inside the injector is a little slow, and does not respond quickly enough to close after the pilot injection, giving too much advance in one cylinder. I've been running 2 tanks of diesel cleaner + 30w non-detergent oil, one quart per tank. Seems to have gone away but i'm keeping an ear on it. Also it may help if you drive it really hard, full power/rpm to give it full rail pressure and wash away the dirt, rust or whatever is causing the stickiness, and clean out the injector nozzles.

 

[Buffalo]

I have an '03, HO, 6-sp, with the same problem. Took it to the dealer, twice, now and they cannot fix the problem.

DC has a series of tests and if the engine does not "knock" during these tests, it's OK as far as they're concerned.

You will have to call DC and get a case/reference number which will, hopefully, put you in touch with a district serv. mgr. , & then, maybe, you're problem will be fixed.

This is the point where I am at. Got the case # & am waiting to hear from the district serv. mgr.

I think what is happening is that one of the injectors is not doing the "pilot injection" thing. Squirting multiple shots of fuel into the combustion chamber during each firing event. It's squirting one, large, shot of fuel and creating a large explosion, like the earlier Cummins engines, therefore, creating the rattleing, knocking sound. I could be wrong about this diagnosis but, that's what it sounds like to me.



Good Luck.



Joe F. (Buffalo)

 

[DBurkhard]

I have a knock in the engine compartment, really notice it more when truck is put into gear- but it will also knock while in neutral or park. I can really hear it well when I am at a drive through- noise bounces off the wall real well. Any suggestions? If I go to the dealer, will trouble codes come up if there is no light on? I would like to go in there with a thought as to the problem. Thanks- by the way- 2003 quad 4x4, so w/47re, stock except for AFE, BD X monitor and 4" exhaust.

Bailman, go to this thread I started a while ago and listen to the clip. Your problem sounds very similiar to the knocking I had. It started as a light tick and progressed to a very pronounced knock. My truck was like yours in that the knock was very pronounced when put into drive, but as it would also knock to a lesser degree when in park. The truck had to be fully up to operating temperature before the knocking started. The dealer replaced one injector and about 6 months later, an additional one. After the second injector all is fine and no more knocks.



https://www.turbodieselregister.com/forums/showthread.php?t=108510



Dan

 

[Johnstra]

It's almost certainly a bad injector. When I owned my 03 I had the same knock. Service manager put a scan tool on the truck and killed each injector in turn until he found the one causing the knock. It's very obvious when he gets the right one. You'll be able to put your truck in park and there'll be no knock.

-john

 

[RAMINSPEED]

I have the same problem. I took it in and they couldn’t hear it of course. On the way home I heard it and took it back the next morning. I pull up and first thing out of there mouth is "that doesn’t sound right" no kidding, that’s why I was here yesterday :-{}. The truck has to be hot and it's real noticeable with the AC on and in gear. I have an appointment to get it looked at (fixed ) in the near future.