I recently put in a new fuel and timing table into the ecu, it works great on 3rd gear pulls... but in 4th around 3500-4000 it knocks... usually around 6s and 7 counts then fads off to 4,3,1 and 0 again. I attached the

here is the log. Any idea as to why?

And the maps are here also.

Any help would be great Thanks!

 

bump looking for some help

 

It might be beneficial to know what mods you have. Have you tried putting in an octane booster and seeing if this cures the knock first?

Failing that, you'd probably want to adjust your timing.

 

Mods are : apexi intake, logic upper and lower ICP, hks dp, UR HFC, tanabe ultra Ti catback, mbc set at 22psi.

I had the tune made for 93 octane... would suck if i had to run an octane booster just to use to tuine without knock..

 

Do you have a boost gauge? I notice that I boost about 1 psi higher peak in 4th gear wot than 3rd gear. My timing was tuned in 3rd, so to be honest I should probably check if I am knocking in 4th myself.

 

heat soak

 

The engine simply works harder in higher gears and is more prone to knock under the same circumstances. If the knock is consistent, you'll have to drop the timing advance.

 

hm i have notice that i spiked once in4th to 23 instead of the tuned 22. So that would make sense. The only thing consistant i've noticed is that when i get 6, 7 counts of knock, the ecu registers a lower ocatne level... even though its all on the same tank of gas. The knock seems to be consistant, so i may retard the timing a bit. hopefully htat helps

 

The octane value you see decreasing is just a value that the ECU uses as a measure of how the car is running. When the number drops from 100 the ECU begins to interpolate with the low octane maps a little. The further it drops, the more interpolation you get. The octane value usually drops after a knock count of 6 is reached.

 

interesting, so when it drops from 255 its because it goes to the low octane map and not the other way around. hm..

 

Double post

 

The octane value drops because of excessive knock ... Here is an example:

Engine: "Yo, ECU, I'm knocking a bit man ..."
Knock: "HAHA!! 1 2 3 4 5 6 7 8 9 10!"
ECU: "Yeah man, I see that ... that sucks. Hey Octane, you getting this?"
Octane: "Yeah, I'm taking note of it ... looks like High Octane Map is a little much right now"
ECU: "Octane is looking a little down ... I need to ease up some. Octane Maps, you guys awake?"
High Octane Map: "I think I'm a little much for this ... maybe Low should help a little."
Low Octane Map: "Why you gotta bother me man? Okay, whatever. I'll help you out a little, but only a little and I'm going back to sleep when Octane picks back up ..."

And SCENE!

 

the first thing I would look at is the fuel and determine whether or not it's right, if it's right and the boost is in check, then look at the timing and pull it back a bit in the are a where knock begins.

 

Agreed if the knock is consistant take a degree out right before the knock starts and you should eliminate it.

Taking a degree out before the knock starts, not where the knock is can make all the difference.

Now looking at your logs you run very low timing in that area.....i run 6-7 degrees at peak load and my afr is 12.0 and i have no knocking issues. I would say do more logs and see if its repetative before making changes.

 

thanks alot guys. i'm gonna run some more logs tonight when its a little cooler and see from there.