I was scanning yesterday and found that my timing would be at 26 deg. Sounds good to me. But it would then retard about 9 degrees upon shift.
This car is the 5.7 TPI auto. I thought auto's weren't supposed to retard on shift....
Also, there was no knock present at the time of retard.

Any ideas? Normal? Something messed up?

 

Anybody?

 

I'm no expert so treat my advice accordingly........

That timing retard you're seeing is due to the fact that when you're shifting to the next gear (i'm assuming this is on upshifts) the motor's rpms go down while the load goes up. So using the rule-of-thumb that timing advances with rpm (and vice-versa) and retards with load (and vice versa), the ecm should back off the timing. Unless you're talking about something else it would sound normal to me....

 

My ECM is pulling 9d too only when shifting from 3 to 4 at high RPM (4200).

I don't think it is a mechanical problem. The car is in a awesome shape.

- My base timing is set to 9d instead of 6d. How about your base timing?

- I am going to back it off to 6d and then scan it again. Try doing the same thing and see what happens.

- If this does not help I will try lowering the spark advance table in the PROM. I might also change the Knock Retard Rate and Recovery rate.

It might be a good idea to replace the old Knock sensor too.

Good luck