12.7 detroit studders and knocks

I have a series 60 that has a loud knock. Seems to be injector issue. Installed new injector on hole #1 still knocking. Unplugged injector harness at hole #1 and knock goes away. Why???!!!

 

Did you do the work? Thats an important piece of infor to make sure it was done right with injector height and etc.

 

Have a knock on hole #1 changed injector and still knocks. When I unplugged the injector harness from hole #1 the knock goes away. Compression test passed. Checked oil pan and lower engine for anything funny.

 

Nope. Came in on the back end of this one. Set injector height and valve lash myself when I got to it. Didnt do the swap of injectors. Checked with mechanic previously over the job to make sure no orings were cut.

 

sounds like possible o-ring issue from the install then

 

What about injector cup damage? Any idea how it looked. If damaged, did you install a graphite crush ring, along with a the big fat O ring, to seal it up?

 

The orings look good. And after all injectors were install a compression test was performed. Held steady for over 3min.

 

If you have a scanner, see what the engine coolant temperature sensor is showing. I had one that had a horrible knock that was there 95% of the time when warm. Every now and them it would straighten out and sound great. Coolant sensor was sending to the ECM the engine temp was 75 deg, throwing the injector timing way off.

I put in all new injectors, two at a time, chasing it.

 

Are u suppose to install graphite crush ring along with fat auxiliary ring on a N2 injector 12.7 ddev 4?

 

Yes,

 

How about injector calibration if i installed new sets?