Engine/Transmission (1994 - 1998) 97 Knock at Idle speed only

[Stark_Ent9802]

Hey Guys..I have been getting my 12 valve ready to go to the body shop to get painted etc.. In the past couple weeks i have installed a new turbo and fuel solenoid, and today got a couple new batteries. I have fired this truck only a dozen times if that in the 10 months i have owned it and NEVER have I heard what i heard tonight when i started it and that was a Clear KNOCK at idle which is set at 1000 rpm. Hard to tell where its coming from... only knocks at idle..as soon as i start to rev it goes away. Oil is full, clean, and pressure is good. Let the ideas fly...what am i lookin at??/ er what am i hearing? Thanks.

Truck is 97 with 293k, Stock...bought it last october for a work truck, but turns out it turned into a project truck which myself and many more Have helped over the last year with cab mount replacement , floor repair ,ect...

 

[hsmith]

Hopefully it is the lift pump.

 

[Cummins12V98]

Isolate the sound with a short pc of hose to your ear.

 

[GAmes]

I'm thinking injector. Crack the fuel fittings one by one and see if one of them stops the knocking noise.

 

[ata]

GAmes, Has got the right place to start. It could also be air getting the fuel system too.