Hi there,

I am new to this forum for posting but have used the advice on here for some time now. I have an issue with my truck and was hoping to get a little feedback...I am getting a knocking sound from my truck when I accelerate hard. I have owned the truck for a number of years and always remember it being there but 3 people have made a comment on the sound in the last couple of months so maybe it is getting louder.

To give a bit of background, it is an '06 crew cab LBZ with ~170,000 km. It started blowing black smoke out the exhaust from what I can remember a few months ago but only when accelerating over 2000 RPM, which to me is normal for a diesel. I have kept up on the maintenance and just changed the oil, fuel filter, transmission cooler lines and did the stock air box mod. I also just installed the PPE standard level 2 tune on it. This was all done in the last 2 weeks. As well, over the last few months I have been adding seafoam to the fuel to help clean my fuel system out.

I have been doing a lot of research on this and can't seem to find what it is exactly. I don't have anything to read the injector balancing rates to see if it is an injector causing me problems. But at $100 a shot to have a garage hook up to it, it is probably worth getting an edge insight to monitor these things for me. Does this sound like an injector problem? Could it be the exhaust, or the transfer case? The sound seems loudest on the passenger side of the truck.

As well, I had a friend drive the truck to let me listen to the sound it make and he said that the truck seems to be lacking power with the 90hp tune on it. Not sure what to do. Any help would greatly appreciated!

 

this can defiantly be an injector issue. sounds though are a hard one to diagnose as none of us here can hear it. is this happening before the RPMs come up or after?

if one or more injectors are putting out too much fuel then that can work as if the timing was advanced and make a knocking noise.

this is where, as you already know, the balance rates can come in handy. the one(s) that are showing negative numbers are injectors that are putting out too much fuel and the ecm is trying to pull fuel to make them equal to the others. if there is one injector that has a real high negative number then this is likely the culprit.

i would first return the programming to stock and see if that does anything. an injector that is dumping too much fuel will only be worse with a programmer.

 

It seems to happening after the RPM's come up. If I accelerate slowly, there doesn't appear to be a knock.

I just tuned the truck a couple of weeks ago and the knocking sound was brought up to me well before that. So it does do it with or without the the tune. I will remove the tune when I am home next and see if it makes a difference.

I would video the sound it is making, but as everyone knows it doesn't do it any justice.

Thanks for the feedback!

 

So I took a video while driving this morning and put it on Youtube. I hope the knock is audible enough....any thoughts?

 

sounds like you need to check the balance rates on the injectors. one or more might be getting sick.

 

MY truck has the same noise and my number 2 injector is on its way out

 

My truck has the same noise. How do you check the balance rates? what do I need. HELP

 

I guess I should have posted what I found out regarding my dilemma last summer...

So I changed the odd bank of injectors and the knock stopped completely. It cost me about $2000 here in Canada and thats with purchasing refurbished injectors from Injectors Direct. All is good as far as I can tell until a few months ago...

The way to check your balance rates is to buy an edge CS or CTS...it has the capability to monitor a number of different things on your ride, or take it ot the dealership and have them use the TechII. They usually charge about an hours labour to do this, and it literally takes 10 minutes to read the balance rates, but they can also do a bunch of different diagnosing with it as well.

Hope this helps, and sorry for not posting my findings earlier!!