U7193 - 04 GMC SIERRA 5.3 (MAJOR WOT KNOCK)

[xxdabroxx]

I am experiencing a very bad WOT knock. I am running the 87 tune with 89 octane fuel. To get the truck not to knock at WOT i have to retard the timing 20%.

I tried to add some fuel at WOT and add some timing back, but it doesn't help. Could there be another issue with my truck?

I noticed, while watching the real time data, that part throttle timing goes as high as 50*. Is that normal?

Also, my speedometer is reading incorrectly. I have 285 75 R16's, and that is the tire size that is in the program. I am really scratching my head on this one.

More info: CAI - Gibson Exhaust - Bigger tires - Stupid Throttle body spacer

[jrmybck]

it is definatly not knock. u should not have to retard the timing. at stock settings the timing is at a correct and safe position. i have advanced mine almost to the max and have no knock. see the numbers at wot not part throttle. mine show 24 stock

[neonhomer]

IIRC, I have the same tires on my 04 Silverado. Ended up adjusting tire size by height instead of size. Works quite well...

Could have a wonky sensor....

[2sscamaro]

you might just have some funky gas. Try running the tank down close to empty and then getting a branded gas like BP, Mobile, Sunoco, etc. from a station that has fresh gas and does high volume sales.

[CANUCKPREDATOR]

Get rid of the spacer, relog and adjust LTFTs, then try the WOT Fueling.