Assassin

iTrader: (3)

ok so periodic kr still present, I'm boosted @ 5.5psi, stock bottom end, wideband a/f ratio 11.0, timing is down to 10* @ 4000 and going up to 12* @ 4800 , the timing was higher but I tried to drop it to get rid of the kr, dosent seem like it made a difference, weather I'm useing 91octaine, 91/100 mix or straight 100octaine fuel, the kr is still very similar, happening at 4000 to 4600 rpm, sometimes 1* sometimes 6*, I know w/100octaine and 10* timing there is no way I should be having kr, but again its not all the time maybe 1 out of 4 times, the compression is between 155-160psi on ALL cylinders, got new tr6's gaped @ .035, I dont think its the tune anymore,
so far I'm left w/ the belt tentioner on my 99 vette or the knock censors are fk'd and giving me goofey readings.... would this be your next move to change tentioner and knock censors?... anything else I should try first?

Assassin

iTrader: (3)

also the iat is in the high 70's

jimmyblue

iTrader: (11)

Have you tried messing with the sensitivity thresholds
at all?

Is this something that happens at closed loop (think
about the proportional fueling periodically swinging to
the lean) or just open loop WOT?

With 5PSI you are well past the stock MAP sensor,
would expect some tip-in ping issues there. Also the
IAT being 70F seems awfully low at boost, unless you
are talking nice winter air. Is there anything modal
about the ping? Can you see signs in the O2 readings
that it's getting lean dips preceding the KR?

Assassin

iTrader: (3)

its just under wot, its intercooled and yeah ambient was in the 50's, I'll check the stock o2 logs but the wideband was reading good...

ESR

iTrader: (7)

If you put race gas in it and it still knocked its false knock especially with 5.5 PSI and 10 degrees of timing........your not getting any check engine codes are you ? like I did the knock sensor low voltage code which will cause it to knock........ but your tune is definitely safe.

Zombie

iTrader: (2)

I agree, it's false knock. I'm dealing with the same issue on a turbocharged 98 z28 right now. We still need to do the 100% 100 octane test, but i'm 99% sure it's false since we had a mix of 100 in it before + alky and it would still pick up random knock with 10 degrees timing. We also see some BIG knocks at part throttle which is odd since the timing is the same and the fuel is reading even richer. It will always see knock 1 frame after the map sensor pegs in the log.

Assassin

iTrader: (3)

I'm thinking its got to be the knock sensors toasted from washing my engine, I'm going to change them and do the rvt moat around them, even though I use a blower to dry the engine and dont start it for another couple hours the water must have puddled in there.... if this dosent do it I'll try replacing the belt tentioner next...., keeping fingers crossed...

frcefed98

iTrader: (16)

I got persistant KR readings when both of my knock sensors went bad. I replaced em with the newer harness and sensors(I have a 98 ) and the KR issues went away.

Do you feel a slight stumble or hesistation(sp?) when getting into boost? Next time out logging get the ol butt dyno tuned to sensitive and feel for that stumble or hesistation...if you feel it getting into boost, thats real knock happening.

J

Assassin

iTrader: (3)

no hesitation going into boost, it feels like it has good power every time going into boost, but after its full psi for a while is when it just feels like it didnt have as much power as the last time.... when the kr isnt there it goes like a raped ape, 1st gear is useless and it starts to light um up at the top of 2nd and sometimes in 3rd @ 80mph, but then I do it again and same stupid problem, just a loss of power... and I'm listening to the engine real close to see if I can hear anything and it sounds just as smooth as you would want it to be... again though, I have washed my engine quite a few times before and after being boosted, I wouldnt doubt that water found its way in there especially that there was an accual gm buliten on something like this..... glad to hear I'm not the only one w/this problem....

WS6FirebirdTA00

iTrader: (33)

you can get knock from being too rich as well, ive seen that on pleanty cars. wheel spin can also give knock and you can get tip in knock wiht too hot of spark plugs. my friends 99 had knock issues and then it threw a code for a bad on, could have one on the way out?

RedWS6 00

Old engine or transmission mounts could cause false knock too.

Assassin

iTrader: (3)

when I had the oil pan out I checked the engine mounts and they looked perfect, its a c5 so no tranny mounts, but the rear diff mount is also in perfect condition....

obZidian

iTrader: (2)

hey guys, got a "new" set of knock sensors, been having tons of what i suspect as false knock.

So, as im doing my fast 90mm install, i have access to the sensors and noticed somthing interesting...

They looked exactly like the new ones i just bought!!! If they are, DOH!!!... and they are the new issue, than im stumped becuz i got a whole lot of random knock. I have logged and logged until i cant anymore and i cant seem to find a pattern...

So, in my sig is a link to my car domain site....plez check it out, on page one i have a pic of the sensors i have in car right now and they are identical to the ones i just recenlty purchased. They have a ACdelco #213-3521 and Gm# 12589867.

thanks!!

Also, the rvt moat mode, this is pretty much just add a ring of rtv/rvt or some sort of silicone sealant around the sensor pocket so water wont get it, right? Isnt that what does stupid foam things are there for?

SmokingWS6

iTrader: (1)

Late model 98's have the 99+ sensors. I found this out swapping out my sensors as well. I wash my engine all the time and when I went to replace my sensors while doing the ls6 swap they were bone dry. I'm not sure why some suffer so much from water damage.

obZidian

iTrader: (2)

when you say late model 98'z, how can i figure this out? Do you happen to know the VIN break or how i can find my build date...i hve no idea unless by looking at the vin, and figuring out the numbers...

Yeah, mine where dry too, i guess. I thought that the foam pieces in the front and back of the valley were there to stop water from getting into the sensors....

Assassin

iTrader: (3)

so did the new knock sensors fix your random kr problem???

obZidian

iTrader: (2)

well, i haven't replaced them yet but i will today...when i get here buttoned up and ready to go, i also got to replace a valve springs, i'll get back to ya...

obZidian

iTrader: (2)

real quick guys, what are the trq. specs for the knock sensors...i know this is important but i cant find through the search..

thanks!!

DrkPhx

iTrader: (15)

The torque spec for the Knock sensors is 11-lb ft. The build date is shown on the sticker located on the inside of the driver door.

obZidian

iTrader: (2)

ok, update...ripped the old sensors i had in and they are part number 10456603/5274-2f They new ones i got are #12589867/4185-1s

Wat gives? Are the ones i had in the car the new design? I think they are...

And wat about the new ones i got? Anyone see this part number before?

UPDATE: If i did have the new ones, than i think i found my problem.. the rear sensor and harness is COVERED in this chalky, whitish yellow/orange residue. Could be water or maybe even some coolant. You guys think i can use the new part number sensor to replace these?

Sunday:

Yesterday, i replaced the sensors i hd, the "new" part number with th eold ones. THe rear sensors was HORRIBLE...that should of been my problem. I added some rtv huigh temp in the pockets along the grommet and added a bit around the top to give it a better seal. They threading in nice and i torqued them done to 13lbs...i was told anywhere in between 12-15 so i opted for 13lbs to be safe...dide want to hurt the sensors of over do it. Hopefully, i'll get the manifold on today and get her started and scanned soon...let see how these new sensors hold up..

over an out!!