Hooked up my AutoXray EZLink Scan tool the other day and cruised around checking out my Knock Retard values. Weather was high 70's and kinda humid. Ran 89 octane, beat on it a bit around town and on the highway. At WOT it was always at 0.0*. I would see 1.2 to about 2.4 during normal part throttle driving under light acceleration and up to about 6.8 when cruisin on the highway between 55-65mph and lightly accelerating. But most of the time 0.0. That sound about right? I've heard that the 99's have been known to have issues with false knock, but I'm pretty happy with with all of the zeros that I see.

 

is this a stock pcm ? i', thinking yes since you are running 89 octane. guessing most of the kr is from the lower octane fuel. seems like under certain conditions you will get some kr no matter how mild your tune is. there seems to be some discussion about whether to tune for low or no kr. i've noticed, from messing with it, that if i back the timing out just enough to eliminate it, the pcm will run more timing. in other words, it seems like if i get any kr at all it pulls more timing than necessary to compensate. but anyway as long as there is no audible detonation, you should be fine. try running higher octane and see if that affects it. e

 

Stock tune, stock cam for the time being.

 

ok. anything else ?

 

I just did my sig...hope it worked. Just in case - K&N FIPK, Gibson shorties, Gibson dual out back, factory .373 posi, BFG All Terrain 285's on stock wheels. Cam waiting for springs on back order 206/212 .515 .520 114 lsa. Considering a custom tune, don't have the $$$ right now. It's my daily driver, so I don't want to go to crazy. I like the fact that I can run 87 octane when funds are short.

Any suggestions?

 

That sounds JUST like my truck, except I'm running 93 octane.

 

Oh god. Another 99 gremlin PCM! The way I see it, the KR battle on a 99 PCM is never ending. Has your PCM been updated by a dealer at all? I fought my 99 PCM and KR till I was so pissed off I wanted to break something. Nevertheless, I had to take te 99 PCM out of my truck because it ran so bad.

 

Ran the tank down until the light came on and put in 12 gallons of 93 octane and a can of Techron. Weather was a little cooler, engine temp around 197-199, same driving patterns, same exact numbers. Runs great though and always see 0.0* KR at wide open throttle blasts.

Gonna try to get down to the track Friday night and make some passes. First time ever.....I'm pretty frickin excited!

 

have fun, like i said if you don't hear it, it's not a problem. your truck will pull better with the higher octane fuel. it can advance the timing further, just because the kr numbers look similar does'nt mean your truck isn't running more timing and making more power. as far as the 87 option, if you want to be able to keep using it i'd forget about the cam and the tune. e

 

I guess I'll have to start buying Budweiser on sale so I can afford the 93, cam's definitley goin' in as soon as I can find the time, hopefully before summer's over.

To answer 99Silver's question, the ecm was supposedly updated a couple of years ago under warranty during on of the dealer's 3 attempts to cure my driveline clunk that I was finally told was "characteristic to this vehicle".

Still debating the tune...also trying to decide if I want to switch the factory 195* stat for a 180* stat...should I start a new thread to get some input on that?