Time failure Code 43 GMC Jimmy 92 American

That such mechanics and fans, I have a doubt or rather I cannot correct the failure of a GMC Jimmy Mod 92 4x4 American.
The problem is that the Service Engine Soon does not go off, I already took codes per flash and takes out the 43 code regarding the detonation sensor or ks, I already changed both sensors because they were damaged, and yet the service witness does not turn off, I already check the sensor line and disconnected gives me 5V, already connected low to 2.5 V, and and in operation the sensors are given to me to read a reading of the sensors. .5 A 1 VCA, when reading the reading oscillates, when putting the truck according to manufacturer 0 degrees, I get exploits, therefore I have to advance the time so that it does not find explosions but it spends more fuel, I need someone to guide me, maybe it is going through a detail through there.
I will appreciate your attention and help, by the way it is Vortec 4.3l engine with a 6 holes salt -type injector