injector knocking

[maverick_935]

At what point do I put the truck in the shop. 230, 000kms and I can hear what sounds like knocking at just off idle sometimes. Other times you hear it acccelerating until you back off for a second.

Once in awhile the idle is also really rough.

Any thoughts?

[Kennedy]

This can be a tough one, but I'd not delay checking it out as a knock can become a cracked piston in short order.

If the injectors are original I'd suggest you consider a set.

[maverick_935]

Well, I took it to the dealer and the what do you know 2,5 and 7 are beyond spec, and a couple more are at their limits. This is not going to be cheap.

Going to replace all eight and be done with it. I figure another 200,000kms and the injectors should be cheaper by then.

No problems with them until now.

[More Power]

I agree with John. If the injectors are all high-time units, and you have multiple injectors with out-of-spec fuel rates, it's time for a full set. On the other hand, we hear from owners who have their second set in the engine, and only one is out of spec. In those cases, as an owner myself of an out-of-warranty Duramax, I'd be inclined to change just that one.

Don't buy your injectors off eBay or Craig's List. Get them from a reputable source that rebuilds them using only genuine OE parts, validates them on a test bench after the rebuild and offers a guarantee.

Jim

[maverick_935]

Mine were new from the dealer, and if I only had one out of spec and I would have considered changing just one but too many were wrong.