I have a Tech 2 scanner and my car had been running like crap. I have been getting a knock sensor code but it hasn't came back and i don't remember which one it was. Stupid me didn't write it down When i check the spark it reads in the negative ( for ex. at idel it reads -42 +or- a few and at WOT its -28 +or- a few ) it never goes into the + even under WOT, my knock retard at WOT jumps to around 8-10 and under light accel around 1-4, and my knock counts go off the wall. I know i need one new O2 sensor it pegs at 1078 for a while then bounce's around slowly, I am ordering 2 new ones tomarrow. Other that that i don't know whats wrong, i think my i have a bad knock sensor but i don't know.

List of mods
CC 305
Crane 10308 springs
Hooker LT's
Mufflex y-pipe w/borla cat-back
Vig 3600 stall
PCM forless tune, but running off stock ECM until updated tune come's back due to new tranny install.

 

Undate, i put in a new knock sensor and it seemed to help alot. The car still runs like crap unless under WOT due to one O2 that is toast. Ordered new ones and will be here this weekend. But in the mean time i still have the negative spark thing showing up on my scanner so anyone have any thoughts?
Thanks Brad

 

The negative number is just your scan tool's way of telling you the timing is BTDC (a.k.a. advance). It's supposed to be like that. Your engine would not even run if it was showing it as +. Some scan tools show no - or + .

 

You also might want to recheck the numbers... it is more likely you are seeing minus 18 to 23deg at idle, as high as minus 43deg at cruise and minus 32-38deg at WOT.

You might want to review my online scanner writeup... all of the above info, including the "minus" sign is covered there:

http://members.aol.com/InjuneerZZ/ScanMast.htm