This may be a stupid question, but here goes. I've read plenty of threads about injector problems, dirty or leaky, etc. One of the early symptoms seems to be noisy or 'knocking' injectors.

What does injector knocking sound like - and where would the sound be coming from? Should I be listening under the hood? In the cab? Behind the exhaust? At idle or under load?

What causes the actual knocking noise?

 

You will know it when you hear it....

If you go to a drive through or some place where you can hear the echo of the truck and idle it in drive there will be a distinct knocking sound..

WIth mine if I put it in netrual or park the knocking would go away...

I used 5 cans of Sea Foam. 1 can each 16 gallon fill up and it quieted it down quite a bit..

Mine has been knocking for almost 9 months or 9000 miles.. Milage is still good and no noticeable adverse affects so far. Dealer claimed there was no problem and normal diesel sound until last time in.. then he told me oh yea I hear it.. thats not right.. do you want to leave it and I'll tear down the engine to see what wrong.. I left quick!!!..

GERRY

 

How fast will the knocking be? In time with the engine stroke or is it faster/slower?

I can hear the usual diesel engine sound, which could be classified as a slow 'knocking' as the engine strokes - does this just get louder with a bad injector or is it a totally seperate noise?

Also, if there is injector noise, how can you tell whether it's just one more more than one - and how do you figure out which injector is knocking?

Thanks for the help - I'm pretty new at this.

 

MikeyT,

First of all, be sure & remove your Predator Stage II module before you take it to the dealer. Don't want to kill your warranty.

I had the "injector knock" in my '03, HO. Took it to the dealer numerous times complaining. The dealer acknowledged hearing the knock but, according to DC's tests, nothing was wrong with the injectors. So, they wouldn't do anything. I even filed a complaint with DC & got a file number.

Later, I read about a TDR member that had his injectors removed & that they were all carboned-up. He started running an injector cleaner additive & eventually cleared up the problem. I did the same thing he did & it worked for me, also.

I used Primrose Power Master 405 & a bit of Marvel Mystery Oil (4 oz./10 gals. of fuel). It took awhile & a 400 mile trip, towing my 25' travel trailer, to clear up the fouled injectors. But, it did work. I think most of the additives that include injector cleaners will do the same thing. Working the engine hard, as in towing heavy, works well, also.

My injector knock sounded like one injector came out of an older Cummins engine. It only knocked when you put a load on the engine & quit at anything over 1400 rpms. My truck has a 6-sp. & the knock would not occur at idle. But, if you put it in gear & let the clutch out just enough to start to engage the clutch (putting a load on the engine), it would start knocking. It's quite audible & you can hear it, easily. There's no mistakening it!!!

Unless you have an extraordinary dealer that you do business with, you may try solving the problem, yourself ( with additives). It might not be a bad idea to register a complaint with the dealer so that you have a "paper trail" regarding your problem, just in case it turns into something more serious.

The problem seems to be that most of us are not "working" our engines nearly hard enough to burn off the carbon that builds up on the injector tips.

I've read that what member Gerry does with the Sea Foam injector cleaner works well, also. I tried it after "fixing" my problem. So, I didn't realize any dramatic change.

Basically, with the Sea Foam, you pull out your fuel filter, drain the fuel bowl, add Sea Foam high enough that you can re-install the fuel filter. Turn the key to the "ON" position to start the fuel pump to eliminate any trapped air in the system. Then, start the engine & run the "crap" out of it. Previous to doing this proceedure, I warmed the engine up a bit so as not to run a cold engine at high rpm's.

If my problem re-occurs, I will do the Sea Foam treatment, first.

Hope this helps.

Joe F.(Buffalo)

 

MikeT
as with Buffalo my early '03 HO had the number six injector started making the "cackle-clack" noise , just off idle, at 6000-7000 miles. The dealer changed mine and no more injector noise.

JIM