2006 UD

[Bsmith8464]

I have a 2006 UD 2000 with the hino engine. 218k miles. Lately I’ve been noticing a slight knock at certain rpms (usually around 1200). Could this be injector knock? I don’t have any check engine lights. I ran some Lucas fuel treatment in the last tank and it seemed better but the next tank without it was back (may be a coincidence). The truck runs fine and at higher Rpms there is no noticeable knock.

 

[greasytshirt]

That sounds like an injector to me, too. Unless it's nailing all the time, I wouldn't worry too much about it.

 

[Bsmith8464]

New discovery... I was putting the fuel treatment in and saw improvement, but later realized that it wasn’t necessarily the fuel treatment, but it was the full tank of fuel. When the tank got below 1/4 the knock would return, but after a fill up it went away. Is there a pickup tube that could be sucking air?

 

[greasytshirt]

There is a pickup tube. Might be worth a look though