88 k-series, 4x4, 5.7.
During acceleration it knocks. Kinda like like low octane knock, but
not as deep as bottom end knock (thank God). Problem is I've never had
low octane knock in 250K miles. A friend who is a mechanic for UPS said
it might be timing. Makes sense because of the way it sounds. It's not
throwing any codes though. All suggestions welcome.
Rockfish
SnoMan - 29 Mar 2006 14:06 GMT
>88 k-series, 4x4, 5.7.
>During acceleration it knocks. Kinda like like low octane knock, but
[quoted text clipped - 3 lines]
>throwing any codes though. All suggestions welcome.
>Rockfish
If you have not had any ping/knock in 250K, you are very lucky as
those engine are linda prone to knock on 87 octane unless the timing
is retarded a lot. GM got it to tolerate 97 by used a spark knock
retard circuit with a sensor on engine. You might check its operation.
The sensor is usually in the block drainplug hole on bottom
passangerside of block. I have a 89 4x4 burb with 176k on it and it
does not ever knock but it has not had 97 octane in it for 16 years
either as I discovered early in its life that it could be made to run
much better with better gas and a little "tweaking"
The SnoMan
www.thesnoman.com