Spark with KR help
08-07-2008, 11:08 AM
#1
Spark with KR help I am tuning with a AEM wide band and HPT and have been chasing KR the whole time I've been tuning, I have noticed that alot of the time a whole "string" seems to start with one cell and through the rest of the accelleration it stays.
I started out with a few more degrees of spark than in the stock table, which seems low in most places, and after looking at other tunes, people usually have more than in the stock table, and I have been removing spark chasing the KR and now most of my table is less than stock and I am still chasing it.
I am wondering if this is not false knock mabee caused by at least in part by the stall converter or mabee it needs the sensors replaced.
My car is a 2002 with only 20,000 mi. on the clock, could the sensors be bad or do they get more sensetive with time?
With picking up the KR, and it shows up on the scanner as such, even if it is false, is this messing up my tune via the VE that I have pretty much right on, "with more spark than I have now" and the MAF that is almost right on...is the spark KR messing up my tune of these tables?
My impressions of the car is it runs strong for the little that has been done to it, I don't hear and audiable knock, but the car is not quiet and it could be there and I just don't hear it.
Can someone help with what is going on and set me in the right direction?
Thanks..
I started out with a few more degrees of spark than in the stock table, which seems low in most places, and after looking at other tunes, people usually have more than in the stock table, and I have been removing spark chasing the KR and now most of my table is less than stock and I am still chasing it.
I am wondering if this is not false knock mabee caused by at least in part by the stall converter or mabee it needs the sensors replaced.
My car is a 2002 with only 20,000 mi. on the clock, could the sensors be bad or do they get more sensetive with time?
With picking up the KR, and it shows up on the scanner as such, even if it is false, is this messing up my tune via the VE that I have pretty much right on, "with more spark than I have now" and the MAF that is almost right on...is the spark KR messing up my tune of these tables?
My impressions of the car is it runs strong for the little that has been done to it, I don't hear and audiable knock, but the car is not quiet and it could be there and I just don't hear it.
Can someone help with what is going on and set me in the right direction?
Thanks..
08-07-2008, 01:08 PM
#3
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There is a knock retard decay rate which you would
want to increase for tuning purposes, and an attack
you should decrease. This will let you see more, what
is going on rather than slam-and-hang.
You should look at what is precipitating the initial KR
hit. Look at the NBO2 sensor voltage and if you see
it bottom out right before the KR then it's a fueling
(airflow accuracy most likely) problem.
There is also false KR like from exhaust banging or
internal engine clatter, which you might have to
consider if the KR is not follwing from a "lean hole".
want to increase for tuning purposes, and an attack
you should decrease. This will let you see more, what
is going on rather than slam-and-hang.
You should look at what is precipitating the initial KR
hit. Look at the NBO2 sensor voltage and if you see
it bottom out right before the KR then it's a fueling
(airflow accuracy most likely) problem.
There is also false KR like from exhaust banging or
internal engine clatter, which you might have to
consider if the KR is not follwing from a "lean hole".
08-07-2008, 03:06 PM
#4
Make sure that the knock software table that your using is the latter version, post 98. With the new sensors (post 98) the knock software GM used is less sensitive. Check tune archives to confirm. I had the problem you are having & this fixed the problem. However, I am using a 98 PCM & began w/ a stock 98 tune file. It's unlikely that your base tune is from a 98 file, but, wanted to note this just in case.
08-07-2008, 11:48 PM
#5
Make sure that the knock software table that your using is the latter version, post 98. With the new sensors (post 98) the knock software GM used is less sensitive. Check tune archives to confirm. I had the problem you are having & this fixed the problem. However, I am using a 98 PCM & began w/ a stock 98 tune file. It's unlikely that your base tune is from a 98 file, but, wanted to note this just in case.
08-07-2008, 11:55 PM
#6
There is a knock retard decay rate which you would
want to increase for tuning purposes, and an attack
you should decrease. This will let you see more, what
is going on rather than slam-and-hang.
You should look at what is precipitating the initial KR
hit. Look at the NBO2 sensor voltage and if you see
it bottom out right before the KR then it's a fueling
(airflow accuracy most likely) problem.
There is also false KR like from exhaust banging or
internal engine clatter, which you might have to
consider if the KR is not follwing from a "lean hole".
want to increase for tuning purposes, and an attack
you should decrease. This will let you see more, what
is going on rather than slam-and-hang.
You should look at what is precipitating the initial KR
hit. Look at the NBO2 sensor voltage and if you see
it bottom out right before the KR then it's a fueling
(airflow accuracy most likely) problem.
There is also false KR like from exhaust banging or
internal engine clatter, which you might have to
consider if the KR is not follwing from a "lean hole".
what is the knock retard decay rate, is this one of the knock tables?
And I have my WB sensor in the LT bung for tuning the MAF for WOT, and I think this keeps the car in OL because it senses a 02 error...I believe,...could this be contributing to the KR?
And I was getting between 2*-4* in some cells and after removing 1* today it was less than 2* and only in a few cells.