Timing issue

[magicmarty]

Hello all.. I have a 96 k1500 gmc 5.0 and I can't get the timing set to zero degrees via the scan tool method. I replaced the cam sensor plus the crank sensor and also a bad O2 sensor. When it's idling the timing advance is around -18 when I raise the throttle to 1200 rpm the timing goes to -35 and no matter which way or how far I rotate the distributor it does not change. I have tried two different scan tools both show the same results. There is no misfires ect and it runs and starts fine. Does the motor need to be at normal operating temperature before the timing can be set? Any advice is really appreciated.

 

[docstoy]

Do a, search forums search, under keywords 1996 k1500 5.7 setting base timing, I think you will find thread that starts out with code 1345 read thru thread this may help answer your questions . If after reading a couple of times if still having problems explain what you have done with no resolution and we may be able to help. Hope this gets you on right track

 

[EJ_74]

Since you used the word advance, I just want to point out that you don't set the spark advance on a vortec. You need to set the camshaft retard offset

 

[Schurkey]

As said--turning the distributor does NOT change the ignition timing. It changes the synchronization between the crank sensor signal and the cam sensor signal.

First Guess: Your scan tools are lying to you. WHICH scan tools are you using?