How to adjust timing on '97 ?

[sailun]

I need a detailed set of instructions to set the timing to -3.5, and set the offset to that revered -1.50 to -1.94 value. I have access to a Snap-On scanner, and can read my current values (about -3.7, and -0.76). I

However, I have no experience in changing the Offset value, using the scanner, so I haven't initiated the time set procedure.. Are there any other settings in here here I don't want to fudge ?

I have been struggling to rotate the pump. I scribed my original position before doing anything.I loosen the 3 bolts, but the pump doesn't want to rotate. I've been trying to rotate it by tapping with a fiberglass rod, and hammer. Pushed the timing from -3.5 up to -4.0, and now back down to -3.7, and never saw any movement off my original marks. Do I really need that special GM tool ?

Pump was replaced in 2002, with 23k miles on it.

Thanks for all the good info here.

[Barry Nave]

You can change the timing but the ECM needs to learn the offset -1.75 ideal. This takes time to get it set right.
I just went to dealer and ask to have timing set to my perferd timing.
Also watched the whole prosses and seen the reading on scaner.
Yes pump is hard to Adj. but it does not take much to change. Pump being to loose during adjestment can really mess up the whole thing.

[sailun]

Thanks, Bnave95. I'm gonna take your advice and have the dealer do it. How many hours did they charge you to do this ?

Also, any measureable results from the change ? MPG, HP, more rattle, neck-snapping accelleration ? (Ha !)

[Turbine Doc]

Sailun did you get the timing set yet, I've got something for you to try I used on my 98 should work on your 97 if still interested.