ideas to negate knock retard only at cruise

[chevypower101]

ok heres my problem I only get knock retard cruising when I go to get on highway get to like 55 mph knock retard just kicks up to 2 or 4 last time it was 7 kr. I've tried removing a little timing from the areas it gets it at from the main octane table didn't seem to help. What table should I remove it from which sensor? I cant find where to add fuel to normal driving just the wot adder. This truck isn't a race truck and has no forcefed applications. I get none at wot im talking tire smoking full throttle 0-70 I get nothing. One thing I do see is my iat always at 120* florida weather thought about cutting an hole in my airbox and running ducting to just behind my grill for more ambient air. I am using 93 octane and I am pretty sure I ruled out all the likely causes for false knock (exhaust not hitting, all heat shields are tightened down, nothing smacking around under hood everything is tightly secured and maintained! I have cleaned egr and know its working ill leave a picture of the main octane table where I highlight the only areas I get kr. Also I don't beat on this truck and throttle position is always like 18-35% when kr shows up at full throttle its fine and idle is all good. I also don't hear any noises or pings I just see it on my scanner. Any areas where I can remove timing or add fuel I looked thru the tables but was unsure where exactly to reduce it but I did notice the egr table was a little high in the area where it does this left a picture where I highlight the areas I need to retard but I don't think this is the tables where it should

[chevypower101]

ok had to pull little bits of timing now im getting very minimal kr seems like I don't have as much power and my bank 2 seems rich..gona check that but it seems like im lacking some power maybe I can remove some tm from the engine section(untouched so far) to get back a few ponies anyways heres my altered timing table compared to stock first pic. Second picture is timing values for alter timing. Are these common areas to have knock retard on stock 5.3 sierras? also everyone has their own opinions I want to change the knock retard attack and decay tables what are safe number everyone changes to them too? couldn't paste a picture of what my timing table is right now but its stock minus the values in the first attachment.

[WS6FirebirdTA00]

Knock is load dependent. Just because WOT is good it doesn't mean it should be ok everywhere else.

Start with fueling curves, is the MAF and VE dialed in? Actually, start with basics, what is the vehicle? Mods?

If you pull timing and it goes away - and you lose power, I would check the fueling. Also make sure you have a good set of plugs at the proper gap. If fueling is great, adders aren't screwing you up and pulling timing doesn't make any change, then I might start looking at your knock sensor settings.

[chevypower101]

ok truck is a 99 gmc sierra 5.3 Ive been reading around about 99 - 2000 year ls1s pcms having crappy settings having tons of false kr picking up engine and transmission noise so I decided to look a little more into it and checked out the repository and looked at some of the settings used to configure 2002 and up. I compared files with my stock file and the settings for the knock sensors are way different I mean its crazy im thinking if I just take all the settings for the 2002+ trucks and copy it to my tune ill be in good shape and I wont see any kr just like the 02+ don't. I took 2 screenshots and posted to paint since that's only way I know how to do pictures but it shows how far apart my table is from what I would think would be a more updated file. 02 has same knock sensors and everything I do believe correct me if im wrong but I should be able to use these tables(there were a few more than I couldn't fit in picture) Any advice or comments let me know I feel I could be possibly picking up outside noises as my truck is nearing the 100k (92k atm) i get up to 6kr and run tr6's gapped to .60 everything is maintained and seems fine no air leaks exhaust leaks and truck never goes over 196 degrees coolant is full clutch fan works. edit -->93 octane used and i don't beat on this truck its always low rpm i see it never over 2.2k rpm...

exp file is the repository 2002 stock Silverado (i checked another one to make sure someone else didn't switch numbers around in tables)

[MikeOD]

If removing timing has caused it to have less knock retard...then I don't think it's false knock...so I wouldn't get too concerned about 99-2000 having a "crappy settings"...I haven't personally ever seen that.

You said it looks like 1 bank is rich...is the other bank lean? Is there a fueling problem from bank to bank? Are your injectors all clean and spraying evenly? Do you have proper fuel pressure? How do the plugs look? Are the wires OK?

The area in the timing table that you highlighted isn't exactly "light load"...it's not heavy load, but it's a decent enough amount of airflow to warrant checking for a mechanical issue before you change the PCM to ignore it.

[chevypower101]

if it was real kr i figure id hear pinging knock something at least. i don't have a wideband and your pretty much limited to what you can do hear without one. I didn't know id get a non hpvi scanner had thought u could buy the wideband later but nah now i have the original scanner with with no where to hook up the wideband....pretty nice should say DOESNT INCLUDE WIDEBAND OR PREOUTS FOR WIDEBAND but it didn't just like 99% of the crap i buy..it feels like when i screw around on the main timing table its fine then i come back with kr in different areas ones i didn't even touch or even worse its weird like driving for 20 minutes you think you solved the issue. I don't see why everytime i have a problem why i never get check engine lights for anything doesn't matter what it is i don't get them. Oh and have you seen the aggressive egr table? i looked at other years and nothing comes close thing adds +14 degrees of timing in certain areas seems a high.. ill check fuel pressure but everything else is good think ill set it to where 02 is at and if it blows up atleast i wont spend money trying to chase down something that probably isn't there. il just save and if i need a new motor atleast i have it instead of trying to chase down the silent phantom knock. Also i tried once i got some knock retard doing 65 i gave it more just just enough to accelerate without unlocking converter withing a few seconds went from 65 mph to 80 knock retard never went up was just slowly going down never went up and i would have been in the area where kr occurs not in the high rpm or high airmass table. also how common is it for these smaller injectors they run 99-2000 years to get sludged and plugged up. I always use techron fuel system restore. I have a whole can of b12 in it with 93. But just because i always run cleaner doesn't mean it can make desposits disappear thru the fuel injector screen. once i check fuel pressure on this i think all my other checks involve removal of the intake manifold...checking knock sensors, harness wiring, checking the fpr to see if its leaking. one more thing id like to add about 99-2000 pcms are i cant even program my door locks like you guys can by dooring the unlock lock thing after doing something with the key. Mine i have to flash with a tech 2 because all the door lock settings are programmed into my bcm instead of pcm..just something to think about how off they could of setting everything else up(other truck i own is a 2000 silvy wish it was 01 or 02 ill snag that ecm in half a heartbeat. k ill see what she reads on pressure

[chevypower101]

fuel pressure koeo 57 lbs
engine running i have 52lbs
under load it drops to like 50 lbs or goes up to 56lbs
seems a ok checks out with the specs for my shitty Haynes manual

if i really thought it was the fuel pressure i have the master test kit with enough hoses i could leave the gauge on my windshield for when i drive but i believe this to be good

[MikeOD]

I don't know what you're talking about...we can't use any tuning software for door locks...and the engines PCM doesn't control them...if you can adjust them in some trucks with the ignition key and something on the dash, that's the BCM.

As for which hardware you bought...on this link http://www.hptuners.com/order.php both the scanner and suite have a link that says "interface differences" next to the option of choosing standard and professional. That link goes to here http://www.hptuners.com/forum/showth...ce-Differences where it states that the pro interface is the one that adds the ability to log 0-5V signals.

[smokestack]

Did you tune the VE and maf yet? The trucks and SUVs can be so rich it causes knock. At least from what i have seen on mine......

[Markmx6]

I was having a similar issue with my truck (2002 4X4 silverado 4.8l)having what I believed to be false knock. It was always partial throttle usually coming off a harder acceleration between 2200-2800 rpms. Would show 8 degrees of KR.... Timing adjustments reduced it, but I was already using stock settings.

I also had a weird idle issue when the motor was cold <50 degrees is considered cold for AZ... That I was told had to do with the intake manifold gaskets not being changed in 260,000 miles... (I don't know if this is true, but I don't mind being thorough and gaskets are cheap) Sorry long backstory...

Important part, my rear knock sensor was heavily corroded. Replaced the sensor and had to also replace the harness to the sensors. Now running a more aggressive spark table I have 2 degrees of KR under heavy acceleration, so I will back it off a degree at those points.

It's worth checking into

[chevypower101]

I was having a similar issue with my truck (2002 4X4 silverado 4.8l)having what I believed to be false knock. It was always partial throttle usually coming off a harder acceleration between 2200-2800 rpms. Would show 8 degrees of KR.... Timing adjustments reduced it, but I was already using stock settings.

I also had a weird idle issue when the motor was cold <50 degrees is considered cold for AZ... That I was told had to do with the intake manifold gaskets not being changed in 260,000 miles... (I don't know if this is true, but I don't mind being thorough and gaskets are cheap) Sorry long backstory...

Important part, my rear knock sensor was heavily corroded. Replaced the sensor and had to also replace the harness to the sensors. Now running a more aggressive spark table I have 2 degrees of KR under heavy acceleration, so I will back it off a degree at those points.

It's worth checking into

ya my intake manifold isn't leaking I sprayed it down im sure my knock sensor isn't the greatest probably original but idk I get no codes or nothing and mine is always part throttle / just cruising anywhere from 1200 rpm to 2.2k otherwise its fine. I just think its weird how the 02 tunes has higher numbers in tables as far as I know everything is about the same as the 99 minus a few things but I don't think they changed knock sensors just the values now they probably figured out these trucks have a lot more false knock once they have been driving around instead of brand new getting tested at the chevy factory. I want to replace my intake gaskets knock sensors and harness and put a new fuel pressure regulator while im done there but kinda short on money for now. I found a few pages with ppl buying the newer computers 02+ and programing the 02+ specs in their I know they do it at the chevy dealer when you complain or complain enough so im going to try out the new settings for on the way to the store. Also one thing I forgot to add I replaced the plugs but they had no black peppered looking marks or pieces of anything clean looking so I cant say for sure that its not knock retarding but premium fuel with octane booster tr6's gapped to .60 stock plug gap and im not sure if it even made any difference. Ill drive and think something works and for a little while I wouldn't see any then bam back again I want to say mines false and if its not... well my new motor will have new knock sensors and harness ..ill report back to my findings after my drive