88 TBI K5 -- Advance or Retard the timing for better performance?

[foxman]

Was noticing that afer setting the timing (to original 0 degrees) the K5 doesn't seem to have the punch it had before. I did this quite a while ago and cannot remember where the mark was originally.
Is it possible that the harmonic balancer has shifted as well?
I have 4.10 gears and 35 ssr's does this constitute a need for a timing change?

Thanks for any helpful hints. /forums/images/graemlins/waytogo.gif


Jeremy

 

[Grim-Reaper]

Stock.

The timing is controled by a number of things. THe truck is equipped with a Knock sensor. If you advance the timing and trip that knock sensor then the ECM is going to dump as much as 20 degrees of total timing to make it stop.

The ECM will run as much timing as it can till it starts to ping. These things use a fuzzy logic and that's why if you put Super in them they will advance the timing a little and then if you go back to regular they will start to noticably loose power till it relearns with the current octane. If you change octane and there is not much reason to run super in these trucks because the compression does not warrant it. Then pull the EFI fuses and reset the ECM and it will retart the timing and cause it to lean the new fuel faster.

 

[foxman]

So was it a fluke that changing my timing back to 0* did result in a power loss? Is there a way to check if the harmonic balancer slipped?



thanks.

Jeremy