Hey guys I know nothing about KR, timing, tuning, or MAF

I am getting knock at WOT above 4k in 2nd, 3rd, 4th, and possibly 5th. At first I thought it was only 4th, but a little more testing revealed otherwise.

I have Stg 2, 2.8", Injen CAI, Interceptor
NgkBrk7e's set at .40 gap



Would the MAF Freq. off of the Interceptor have anything to do with my KR i'm getting?

What should the MAF be at, idle, or WOT?

Should I shorten or lengthen the gap on my plugs to help stop the KR???

How can i get rid of this damn knock?

What MAFF are you seeing at WOT?

The easiest way to correct this is bettr gas, less boost, or less timing. I would also try putting the stock airbox on and seeing if that changes things.

I was able to get another 2 degrees of timing by calibrating my MAF table. Do a run and scan the car, then take the MAF histogram, and put those values into your MAF table. I took the average of 3 runs for mine. It worked great.

how do u change timing? and how do you record runs with the interceptor

thanks for the help guys ive been trying to figure this stuff out for awhile now

and what are good MAFF numbers????

Helps your car to know how much air your car is sucking. You add timing by changing the spark map.

do u change the spark map with HP tuners?

and what are good MAFF numbers to be reading???

I don't know its car spacific! Yes you change the spark map with HPT.

hey thanks for the help blown

What are your typical LTFT. My first thought is that your maf is reading less air than is actually entering the car, this would result in a leaner afr and more timing since it thinks it's under less load than it is.

You want all your trims to be between + or - 5

Your better off getting your LTFT at 0 to -4. Positive LTFT means your adding fuel negatives mean the computer is pulling fuel. I got my car down to 0 to -3 just takes time to get them there.

Actually your BEST off just getting a wideband.

should know this by now but what is LTFT

Long Term Fuel Trim
and STFT is Short Term Fuel Trim

and those are viewable on the Interceptor right?

how can you change LTFT?

taking off my intake?

Long term fuel trims are minor corrections the PCM makes to compensate for things such as weather, wear and tear, incorrect fueling values, etc. It determines these values by fueling the car the way it has been tuned and then comparing the a/f by using the oxygen sensors and making adjustments to the values to achieve the deisred a/f.

Adding aftermarket equipment, ie. larger intake tube, will cause large trims if you don't recalibrate the MAF. Its a sort of countermeasure used to keep the car running at peak efficiency.

Yeah, thats why calirbating the MAF table helps so much. My LTFT used to be between +1 and -5. All over the place, recalibrated the MAF table and the LTFT went to between 0 and -3 :twothumbs

think of the maf table as the baseline that your ecm uses to find 14.7.

LT/ST fuel trim are the means to change that baseline.

You want those LTFT's 0 to -4 because when you goto PE, this baseline is used alone without LTFT's to correct it.

In a long about way, my calibrating your maf your giving yourself a strong stable baseline for fuel at PE/WOT, part throttle cruise is always balenced out by LT/ST fuel trims.

You want those LTFT's 0 to -4 because when you goto PE, this baseline is used alone without LTFT's to correct it.

In a long about way, my calibrating your maf your giving yourself a strong stable baseline for fuel at PE/WOT, part throttle cruise is always balenced out by LT/ST fuel trims.
Very true, however in PE fuel trims will be calculated into fueling if the trims in those cells are positive. If they are negative, they will default to 0 for that cell. As always, trim measurements/corrections will always lock anytime any type of enrichment is introduced.

and you adjust ltft with hptuners

You don't tune the LTFT directly, you tune other things so the computer knows how to make your car run more efficiently.

my "long trim B1" as read on the interceptor, was all over the place during normal driving....from -2 to 14

at WOT it was between 1.5 and 8

wtf????

You need some tuning.

definitely but i don't know enough about tuning to do it...and i don't know anyone around here that is knowledgeable enough for me to trust...dammit

maybe il just go back to stage 2 setup and take off my cai

Why don't you contact Tofu? I know he was planing on doing tunes and stuff.

Make sure you are using premium fuel, from a good source.

i use 93 from BP everytime... maybe i should try mobil?

two very important things to understand here...

1. octane doesnt change ltft/stft, you should only be worried about octane as a last ditch effort to lower knock retard or to run more timing.

2. when anyone talks about your ltft's being between 0 and -4, they mean an average over a given drive/run. you will always see some -+, whats important is that the average is correct.
its impossible to get this data from your scan gauge, you need a true datalogger or hp tuners.