So after finally getting my truck retuned for deleting the egr and the worked over and ported heads, I through the tech 2 have discovered that I am getting all kinds of knock retard. My timing under WOT goes down to 18 degrees which would explain why my truck feels like it doesnt have the ***** it should. My thought is that the knock sensor is picking up vavle train noise and detecting it as knock. Anyways I just wanted to see if anyone else has any problems like this. I think Im just about done with this mail order tune crap and its time to go dyno tune or HPtuners or EFIlive. Thanks

Alex

 

with your own tuning software and im sure with a mail order you can turn the sensitivity down on the sensors. do a search for knock retard there are many posts about this.

 

It could be that or maybe some of the Spark multiplier tables are pulling timing.

 

I know nothing about big blocks but that's a common problem with small block LS engines after a cam and/or valve train work.

With HPT, it's a snap to reduce the KR sensitivity. I assume the others are just as easy.

My HPT is licensed for all '02 Avalanches. If you were close to me I would be glad to do it for you.

 

my opinion is if you are going to spend that kinda money on engine work, the extra cash forked over for HPT or (what I have) EFILive is worth its weight in Gold. Really is nice to be able to dig in and make adjustments and record the results immediately to find out whats going on. The 2002 and older 8.1L OS's I have looked at have a table to desensitize the knock sensors (B6228 in EFILive), the 2003 and up 8.1L OS's do not. Just be absolutely sure its false knock before you go making adjustments. Throw some 110 in there and see if it effects the KR, if it doesnt, its most likely false. Download the EFILive software from thier site (its free and the same as if you bought it) then go to the "holdens" site and download (also free) a few 8.1L stock tunes and have a look for yourself.

 

The easiest way to prove that it's false knock is to fill up with high-octane unoxygenated unleaded racing gas. VP Street Blaze 100, for example, is about twice the price at the pump as 91-Octane Premium Unleaded is out here. You just have to find it...

The fuel will definately prevent real knock.

 

James, ya I was thinking about doing that. I milled the heads .040" which made the chambers about 105cc bringing the compression up to about 9.5-9.6:1 which isn't all that much compression but you never know with gas these days. I pretty much always run mobil 93 octane to keep things consistant but Id still like to rule it out. When I get back from FL in july and take the truck out of storage I will pick up either Efi live or HP tuners but I gotta do some research to see which ones best for me.

Alex