unforgiven

I'm working on tuning my 98 TA A4. I have 2 timing issues. First is what appears to be burst knock indicated by the scanner (SnapOn mt2500)under WOT operation. It indicates 3-4 degrees of knock retard without ever indicating knock 'yes'. Second problem is that the indicated timing advance under WOT is anywhere from 4-8 degrees lower than programmed in the timing tables. It appears that at times it is averaging timing between the low and high octane tables. I am using tunercat to tune it and I can't seem to find any tables or constants relating to burst knock other than burst knock vs coolant temperature. I would swear I have read about a similar problem on here before but I could not find it by searching. Any help would be much appreciated.

Shallow Bay

iTrader: (3)

It sounds like either a spark modifier table or the notorious 98 knock sensor problem.

https://ls1tech.com/forums/generation-iii-external-engine/736391-somthing-every-98-ls1-owner-should-do.html

unforgiven

All of the modifier tables that I have examined appear to have no effect at the temperature, throttle opening , map reading, etc. that I am operating in. This is the first time I have heard of the knock sensor issue. This car was built 6/98 but I suppose I will have to pull the intake to know for sure what is in there. It would appear that 98s are the 93s of the LS1 F bodies.

dummer

I went to update the knock sensors on my '98, only to find it already had the newer ones. Door sticker says built 6/1998.
Not to say you definately have the new ones, and also it's been a known issue that the knock sensor connectors can get corroded from water getting down in the intake valley. there is a GM TSB on it.
I am no timing guru, but check to see if you motor is going lean at the RPM/iraflow areas where you are getting KR.
Also, from what I gather from these forums, the PCM constantly interpolates between the high an low oct. timing tables depending on knock activity, so there might be why your logged timing does not match the high octane table.
But are you tuning SD mode without the MAF? Because then the '98's only use the backup VE table, and I think only the high oct. timing table as well.

gun5l1ng3r

Where on the door sticker does it say when it was made?
And is it true that the dealer can tell you if you had the older or the newer style knock sensors just by typing in your vin number?

unforgiven

If the PCM sees a maf failure it uses the low octane tables.

Production date is on the door sticker in MO/YR format.

gun5l1ng3r

How can the dealer tech tell if you got the old or new style of Knock Sensor?
Is there a list of parts that where acually installed on each individual car...