Injection Pump Rattle

[GreasySub]

I have a 90 Suburban with a 6.2L NA motor. For several months now there has been a terrible rattle coming from the injection pump. It is most noticable at idle and it is not constant. Sometimes it goes away almost completely. I'm relatively new to diesels, so I'm not sure what is "normal" for an IP. However, it didn't rattle when I first bought the truck a little over a year ago. I notice no performance problems, the pump seems to function normally -- the engine has plenty of power and no smoke.

I would appreciate any suggestions. Thanks

[BobND]

Check to see if brackets attached to IP are tight.

(Some rattles are related to engine harmonics, and if your idle is set to a certain speed, they will be worse.)

Also, a worn timing chain can make ALL KINDS of noise.

[GreasySub]

Thanks. The brackets all seem to be tight. Its been so hot here that I forgot - The rattle doesn't happen at startup when its cool outside. Only becomes apparent when the motor has been running a little bit. Even then intermittent. A light tough of the accelerator makes the racket virtually disappear. Does that point more towards timing chain issues or something else?