i have what sounds like a rod knock. i really don't think it is though bc it only happens under a load at 1700+ rpm. never idling or on decel or even engine braking. it's pretty noticable and has me worried. can anybody tell me *** this noise is? thanks
mark

 

Oil analysis will tell you if youve worn through any of the bearings.
Does the truck smoke oddly when its making the noise? Does it misfire?
Could even be a fuel problem in the pump or an injector.
Id just go through the truck and look for other things that might play into it. Make sure the turbo isnt leaking oil, check your timing and valve lash, check for leaks in the air intake plumbing, etc.

 

My bet is bad/worn injector.
I'd pull and have them tested or just swap for some different ones.

 

truck isn't doing anything out of the ordinary and runs strong. from what i've read, it seems like a lift pump or injector. which one should i do first? also, if my injectors are bad, should i have them reworked or get aftermarket ones? do aftermarket ones make $500+ worth of difference? i already have a fuel plate. thanks

 

Check the oil and coolant to make sure they are not mixing and also is it still carring good oil pressure, if not you might have a crank barring going out.

 

everything is normal other than the noise it's makin. almost positive it's a lift pump or injector. is there any way to tell which before i tear it down. i wish it would do it at idle so i could listen to it under the hood but it doesn't start til higher up in the rpm range. thanks

 

well the injectors are not hard to pull so just pull them out and you might be able to see which ones bad if one is real sooted up on the tip if not send them out to don m and get him to check them and make them big!

 

Might be time for an upgrade, heh heh.
Its nice when you get an excuse to add a few horses. Maybe some DDP's?

 

Only good way to check the lift pump is to measure the fuel pressure.
Instructions> https://www.dieseltruckresource.com/...41&postcount=9

Once you have a gauge in place pressure should be 17-22psi at idle and 25-35 at 2500 rpm, no load.
If you aren't getting that pinch the rubber return hose that passes behind the fuel filter with pliers. The pressure should shoot way up. If it doesn't the lift pump is bad. If the pressure shoots up but doesn't reach spec when the return isn't pinched then the problem is your overflow valve.

 

update..
pulled injectors and had them cleaned. shop said they were perfect. put 'em back in and no go. it's getting worse and driving me nuts. is there any way it could be an exaust leak? everything is so **** noisy anyways, it's hard to tell exactly what it sounds like. it only does it under throttle with a load. for some reason, even if i try, i can't get it to do it in 4th gear. 1,2,3 and 5 yes. any help would be appreciated. thanks

 

Exhaust leaks can make for some terrible noises but are easy to track down by looking for soot.
Also make sure no part of your exhaust system is touching the frame or body.

 

Post a Video clip.

 

turns out, it's my tranny. it was getting louder and louder and finally i realized it wasn't the motor. tranny is going to the shop tomorrow after i drop it but i pulled the pto cover and there was a bunch of teeth broke off the front gear set.