Question about checking timing..

[Phil Holmen]

A Friend of mine has a Snap-ON Mt-2500, is it possible to use thins scaner to check and possibly reset timing and to do a cylinder #1 seek??

[GMCfourX4]

You can check timing with the MT-2500, and it is even possible to do the TDC learn procedure, but it isn't like on a TechII where you can push a button (the MT-2500 doesn't talk back to the computer like a TechII can). It will give you a procedure that's something like "Turn the key on and off 27 times in 13 seconds while patting your head, rubbing your tummy, and pumping the throttle and brake pedals alternately" :D Seriously, there is a procedure to "induce" the TDC Offset learn without a TechII, its just a pain. You can definitely use it to find out what your current pump timing and TDC offset settings are.

-Chris

[Kennedy]

From what I've seen, the Snap On scanner returns wacky numbers for TDC offset, AND there is no known (least to me) way to reset the learn without scan tool command on the 94-5 trucks...

[sailun]

posted 11-15-2003 11:15 AM
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Hi, folks. Along the same line of thought,
I'm on a mission to increase my fuel economy and performance. I've read quite a few posts about changing the offsets.

Can someone tell me how I would go about changing the Timing Offset to this preferred -1.94 to -1.50 range ? I have access to a scanner, and am seeing my base timing at -4.0 (was -3.5, before I started fooling with it), and my offset at -0.76. Do I actually use the scanner to change the offset value ?

What's a good starting point ? Set it to -1.50 ?
And , what the heck is offset, anyway ?

Does anyone have any measureable results (mpg, hp) to publish ?

Thanks for everyone's good info.

Kevin Unsworth
'97 'Burb 6.5 TD 'F', 88k miles, 3.73.
Amsoil airfilter and lube oil.
pump replaced in 2002 at 23k miles.

[Turbine Doc]

John,
Define wacky numbers, I think you are right on 94-95 TDC, I think OBD II allows TDC learn with a read only scan tool; but I have successfully reset both my 98 & 99 PCM's using MT-2500 unless I'm doing it wrong.

Chris only 1 key on key off evolution required with AP pressed to floor to initiate the learn, key here though engine must be at 170F op temp before learn can be initiated. MT2500 is 2 way device if you have correct cartridge, but not as capable as Tech 2, is capable of limited commanded tests, time set is one(not TDC offset, different thing), but can be found on ebay for good price.

John I'd like to email you procedure I used for validation, so I'm I'm not putting out bad info, I sent to Charlie P to see what he came up with.