Too much knock retard and not sure whats going on?

[Mep_q8]

Well I've tried almost everything to get rid of my KR, but nothing seems to be working... I took off all TM as i heard that by be a factor, but it didn't work out. I then decreased my Spark advance in both HO and LO tables and that still didn't do much for me...

Even on my stock tune from the factory I was getting KR, and more then what I'm getting now with a few tweaks... So I've come to the conclusion that the reason I'm getting it is because of the mods I've added such as Headers and CAI.

So I'm thinking now what I might porbably do is just go ahead and play with the VE tables... My idea of them is very limited, so i'll post up what i think I might have to change and plz let me know if I'm heading in the right direction or not...

Ok, well I'm gonna look on my KR histogram and see just whereabouts I'm getting KR. At this certain RPM on the VE table, I will decrease some values and start some logging, if I get more, then I will increase the values at this certain rpm... Would you guys say this is pretty much the whole idea based behind VE tuning???

I'm getting my WBO2 tmrw, so I'll weld in the bung and take my car out for a really loooong drive and see what happens...

Can I just ask, what is the Load % related to??

[Mep_q8]

well ive actually just taken most of my KR away...did a few logs and runs and I'm getting on average 1 KR to a few cells... I'm well happy!! i think this should be a safe enough tune in the long run, my stock tune was getting something like 3-4 on average!

I didn't change the VE, all I did was change the spark advance tables a tiiiny bit, took some more TM away and it did well!

My IAT is always in the red though, Its about 160-180F.. I guess that has something to do with the weather over here... its 10pm at night and i clocked a 43Celsius!! Might need to invest in some pipe wrap :P

[zq8bob]

I think you just pointed to the cause of your KR right there. Your intake temps are a good bit higher than what GM might have put the truck through when it was being deveolped. I know my truck, on a bad day is about 100 or so. Wrapping your intake pipe isn't gonna change the fact that your ambient air is still 120 to 140 degrees.

Hotter intake charge means a much higher instance of detonation... and detonation is what the knock sensor is looking for.

[jaronow]

i think your IAT sensor is no good then bro.... unless your intake is that crappy... my IAT sensor says i am pulling in 102-106 degree air down here in tucson during the day and it is 102-106 outside as well, and that does cause some problems.... is you intake enclosed under the hood??? i know when i added ram air to my colorado my intake temps went down considerably

also have you looked at the IAT Spark menu under the spark advance tab?? i know mine was set to start pulling 5-6 degrees and more once intake temps reached over 120

[zq8bob]

He's in Kuwait, and I can speak from experience... It's that damn hot there this time of year. 170-ish intake temps are beleiveable during the summer, mid-day in traffic.

[Mep_q8]

you intake enclosed under the hood??? i know when i added ram air to my colorado my intake temps went down considerably

yes it is under the hood, i am thinkiing about putting a TBSS type duct through the front grill to get that extra air in, or better yet something on the bonnet to suck it the cooler air, but so far its just money that stands in the way! being a student and all...

[jaronow]

i see.... i didn;t realize you were in Kuwait.... man those are some hot intake temps, my truck feels like a slug with 105-110 degree intake temps in the middle of the day. i don;t know how the intake and all is set-up under the hood of the trailblazer, but over at coloradofans.com we are making ram-air intakes for like 50 bucks in parts and a few hours worth of labor, you should go over there and check it out

[Mep_q8]

cool, im gonna head over there and take a look

[Mep_q8]

I've just taken a look at it.. the intake does look similar, but i know for a fact there is NOOO extra spcae under our I-6 engines round the front...I noticed how they took the radiator out to get the "ram" air effect... how on earth would he have space to put the radiator back in??

I would like to do this, I still have all the factory airbox housing left with bendable pipes... I might take the big plastic base where the air filter lies on off and see whats under neath, and do a "jap" style cold air intake

[jaronow]

well take a look at this.. this is how i did my set-up, the big diff is that you cut a hole next to the radiator and bring the intake down that way

https://shell7.tdl.com/~jags/Pages/P...ld-intake.html

[Mep_q8]

niiice, i'll take the car down to the garages tmrw and see if i can custom fab something up for this.. cheers for the link

[Rodimus_Prime]

One thing I did on mine to eliminate some knock was the CASE learn procedure, it especially helps if you have swapped cams

[DaFlyinSkwirl]

hey matt, what is CASE learn? i see it in the scanner, but i have stock cams.

I just filled up with super (still got a 1/4 tank of regular) and advanced my timing in my HO PE table 5 degrees from 4000RPM up. It pulls and feels and sounds great, but I was seeing at the worst 13 degrees of retard in upper RPMs. any ideas? will CASE learn help me out?

[Mep_q8]

but I was seeing at the worst 13 degrees of retard in upper RPMs. any ideas? will CASE learn help me out?

damn, 13 degrees of KR! that does seem a bit dangerous from what I know..I get worried when I have over 5degrees of KR...

[RomansDesigns]

Rather than mess with the main spark map, if the vehicle runs with out a lot of KR when it's cool outside, then I don't mess with the main map, I would use the Intake air temp map to pull timing. That way you get all the timing you can run when it's cool outside and just pull the minimum out required to keep KR at bay when it starts getting hotter.
Mark