i have several questions. i just got my 6.2 back in the truck and running and it is still knocking. its not an oil prob, and the main and rod bearings were replaced. what could make it do this? could it be bad fuel or the injector pump? any suggestions on where to start?

 

Inj pump, wrist pins loose, rod journals out of spec, valve train, fuel pump (if it's mechanical), clutch (if it's stick shift). Take your pick!

 

does anyone know how much pressure the fuel pump(mechanical) should put out? also do yoh have to remove the intake to replace an injector pump?

 

Normal fuel pressure 38-45 kPA (5.5-6.5 PSI)
Normal fuel volume 237 ml (1/2 pint)

 

how can i check that? should i go ahead and replace the injector pump or try something else first? i know it isnt the wrist pins becuase i checked them when i had the crank turned and replaced the bearings which i initially thought was the problem. now that i have eliminated all except for injector pump, injectors, or bad fuel(if that is possible).

 

I am in the same spot with my Cummins, only I have replaced the fuel system and head also. Discribe the knock, I am just curious, I have no answers for you.

 

Is it your first 6.2? Those things always rattle something awful, are you sure it's abnormal?

 

Yes, this is my first 6.2 but it is definantly abnormal. when I first got the truck it ran fine. I was driving to school one morning when it started I was sitting at a stop sign. I thought I lost oil pressure and I had already come to close to locking up the engine so I parked it and started the rebuild from then till now. now that it is all back together it still knocks. I put a pipe to the valve cover and listened to the rocker arms and everything is fine. it sounds like rod bearing knock but it is coming from the cylinders. I went and bought a haynes manual today and it has a troubleshooting guide that specifically says rapping noise coming from one or more cylinders sounding like rod knock, and its saying it could be the injectors. That leads me to my next question. Where do I get them tested?

 

I don't know if they all can test injectors for light trucks, but most 18 wheeler repair shops have injector testing equipment. One down here tested the injectors off my 3 cyl Perkins.

 

any GOOD diesel shop should be able to either test em or tell you where to take em. You sure it isn't piston slap?

 

yes i'm pretty sure that it isnt piston slap. when i had it apart the pistons felt how they should have, and the wrist pins weren't loose, so like i said its either the injector pump or injectors.