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Measured inj timing ?

I assume that you are using the borrowed tech1. With gmtdscantech the number to go for WHILE IN TIMESET mode is 3.5. Measured and desired are different numbers from timeset. Engine must be up to a minimum of 170f to do timeset and tdco learn. tdco learn is done after timeset is done. tdco should be set at -1.5 to -1.9.
I've never used my tech1 to time.
 
The important thing to note from bk95td's post is WHILE IN TIMESET, as he put in upper case. The desired will drop to 0, and the actual/measured will be showing you as low as the IP is able to step down to, like a base timing, although not exactly, because it steps down to get there.

WHILE IN TIMESET mode actual/measured numbers fluctuating between 3.5 and 3.9 would be good. When you get to 4.0 actual/measured WHILE IN TIMESET when you go to perform the TDCO RELEARN it will end up -2.02 and set a diagnostic trouble code.

If not in timeset mode the PCM will adjust it according to programming and desired wont change. I have moved the "base" to 8.0 degrees and seen the operation desired at 7 while measured wont go below the 8 degrees, so it really does work as a "base" in that sense. These are camshaft timing values, so crank would be twice as much. This is why when you set it to 3.5 the actual crank timing is 7 degrees, and when you are idling normally at 8.5 or so degrees crank timing is 17 degrees. Thats pretty far advanced for any engine at idle. Our prechambers slow combustion, so it has to be injected a little sooner than most engines.
 
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