oK, since nobody could diagnos my pinging sound with acceleration on my previous thread, My 2005 3500 with 170,000 miles decided to start making another noise. My fuel lines between the fuel rail and the injectors are knocking. From inside the cab it sounds like exhaust leak. But when I pop the hood you can feel knocking lines. some more than others.Also occasional fuel smell. Injectors right?

 

I had knocking fuel lines on my truck. Check the clamps that pinch the lines and make sure they are good and snug. I thought I had an injector going down or a dropped valve seat. I did an oil analysis and found all levels excellent and no power loss or codes, just the knocking fuel lines. Took it to the dealer because I still have warranty, and was a little embarrassed when they came back 20 minutes later and told me what they found. Just my experience, hope this helps.
Wood

 

Man, that would be great if that was the problem. that wouldn't make my truck stop pinging and running rough would it?

 

Man, I wish I had some better advice to give you on this one. Do you have power mods, ran some good injector cleaner lately, air filter, fuel filter? I used some Stanadyne and it's excellent. Might post this again in the 911 section, there are some Dodge techs that watch that one pretty close and have helped me pretty quickly in my posts. Probably wouldnt be a bad idea to get an oil analysis done, it will show if anything is starting to get out of whack. There might be one in one of the Semi truck lube shops, I got mine done for $15.00. Post some more info surely somebody has some better insight on this than I do. Hope this helps.
Wood

 

Yep, check the blue plastic clamps. I had the same problem and I would have never thought it could have been that loud.

 

so the blue clamp is located on the drivers side of the block? i might have to check mine, just noticed this sound 2 nights ago and its kinda go me concerned.

 

I have no mods, just stock. I am a little red kneck so I took an old broom stick and held it on the fuel line before each injector, and then held the other end up to my ear and had a friend push on the throttle. It was very easy to isolate the noise it is on #1 and #6 injector. I will update after posting on 911 thread. Thanks.

 

It's pretty simple to find, they are little metal clamps that have some blue insulating plastic(or something like that) in between them and the injector line between them. There is a small bolt or screw that tightens the tension on the clamp, which I'm sure over time will loosen a little or the blue material might wear in enough to allow the pulsation of the injector to telegraph through the line and make the sound.