After all of the new perspectives on the injector knock issue have been brought up here recently, including the sound file kindly provided by CADan, I decided to take my truck back to the dealership for them to take another look. It had been making the injector knock sound for a while and it sounds exactly like that sound clip under the same conditions.

To make a long story short, they said that noise is normal. When I asked if they did the injector cancellation test or power balance test on my truck, they (the service engineer manager) said they can't do that with my truck, they can only on the new 600 engines. I've read information from several sources that definitely states the opposite is true, and I really believe they are feeding me a pile of BS.

Anyways, is it possible to rent this diagnostic scan tool so that I can do this test myself? Alternatively, can I take my truck to a non-Dodge diesel shop and can they do this for a small fee? Thanks for the feedback.....

 

Have you tried any diesel fuel additives to see if the knock goes away?

MikeyB

 

Seeing you have an 03 to tell you the truth I'm not sure if you can run those tests on that truck. I've done an 04 and an 04.5 for sure. I do know that you can cancel each injector manually by removing the line from the rail and installing a special tool that basically "caps" the pressure. DO NOT...DO NOT loosen lines while the truck is running!!!!!! We're playing with some incredibly high psi on these things.

 

Hmmm.... maybe he was correct after all. Funny that an 03 would be different from an 04 for doing diagnostic tests.

I have Power Solution's Diesel Kleen in there now, and after 1/2 tank, there's no change of the knocking sound.

 

The scan tool should be able to shut down each injector individually on the '03.
If the fuel additive doesn't cure the knock take it in and have the injector bolts re-torqued. A few '03s got out of the factory with improper torque which will loosen up over time.

MikeyB

 

Thanks for that suggestion, but I already heard about that and checked for any loose injector fittings. Cylinder #1 at idle and in gear is either not firing it's pilot injection or putting too much fuel into that cylinder. The knock is a pretty standard diesel sound that the other cylinders do, but more quietly. Also, I can even feel the combustion event by touching the fuel injector line of the #1 cylinder that corresponds to the knock sound.

I might ask Autozone if their ODBII code reader will do this.......I doubt it though.

 

It's not the fuel fittings, it's the injector hold down bolts (2). The valve cover has to be removed to access them. BTW, I believe it was the #1 injector that was coming out of the factory loose.
To control the injector firing the DRB III scan tool will be needed.

MikeyB

 

Before you waste your time chasing the "thump" on the #1 injector line they ALL do that. I've already chased my tail on that one a long time ago.....

 

MikeyB, good info about the hold-down bolts. I get the truck back today, and I'll check er' out.

JBODY, do you mean all #1 cylinder fuel injector lines on different engines or all the fuel injector lines on the same engine make the "thump"? I grabbed the other the fuel injector lines for cylinders #2-6 on my engine when I notice the pulsing in the #1 fuel line, and I hardly felt anything in the others.

 

The #1 line on the common rail systems have a thump. The rest do not.

 

BTW, the hold down bolts for the injectors need to be torqued to 89 in. lbs.

MikeyB

 

do you mean the full valve cover has to be removed or just the black plastic cover over the valve cover

 

Its also important that you alternate a quarter turn when torquing to 89 in lbs. so never turn more than 90 degrees till you reach that setting.

 

Let me clarify that a little better , there are two bolts for the injector hold down , with the CR engine , alternate between the bolts a quarter turn.

 

surely they can't be that loose.