Ok.. here it is, I have a noticeable tap /knock. Did not know for sure what was going on so I adjusted the valves tonite. Did not notice any out of adjustment real bad. I have a slight miss, and the tapping/knock noise is noticeable @ idle and goes through the rpm range but I can't hear it pass about 1700 rpm because of engine noise. Any thoughts : Dropping a valve, injector, I got the stethascope out and there is a loud tapping on # 1 Injector line..tanks for any ideas..

Scott

 

I'm no expert, but I'd guess that if you had a valve or valve seat going you would have noticed it to be out of adjustment, so I'd be thinking injector...

 

Well I hope it is a injector rather than a valve geting ready to drop.. any others got any ideas?

 

no one else got any ideas.. You can feel the noise and vibration in # 1 injector line does mean an injector?

 

i too have the same tick or vibration in # 1 injector line . 4 of the stock injectors went bad . all six replaced at 64000 miles. new ones installed and still have the tick. even the old stock ones had the tick. but goes away after a couple mins.

 

I have been chasing a mysterious whistling sound all over the intake manifold/rail zone with a stethoscope and all the high pressure lines have a tapping sound, seems loudest on #1 line. And my #1 line and relief valve return also whistle, anyone else ever heard of this before????

I don't think the valve seats are pressed in on the cummins, so if valves are not out of adjustment i would think injector. When i lost #1 injector i had a miss/knock at low rpm's and white smoke at start up.

 

Injector #1 does not have an isolator on it so it will vibrate more than the other lines. You could get a flow test done or if you have the time swap injectors around and see if the tick follows the injector. just ideas for you.

 

hmm what about taking to a dealer and having them do a cylinder injector kill test.?

 

that would work also but it may cost if not covered by warranty. just found out to do a flow test on my son's truck dealer wants about $360.00cdn and another diesel shop wanted $92cdn each.

 

Oh yeah I am out of warranty buy a long shot.. 269,xxx miles..okay The only thing i can figure out is it is an Injector.. unless somebody has any other ideas.