Right now Im helping my friend tune 90 N/A with haltech installed. With the engine fully warmed up when we zero the timing (Hitmans way) timing locked at -5 deg its right on both leading and trailing marks. But when you turn the timing lock off the leading and trailing both advance 20 deg. The timing on the haltech is set at 5 deg advance from 0 to 2000 RPM with the trailing split 15 deg under 2000 RPM. I figued with the timing lock off if I have it at 5 deg advance on the timing map it should stay there even with the timing lock off. Can someone tell me what is going on here? I tuned haltech on my TII engine and zeroed the timing the same way never noticed this. Maby I should check it.

 

If timing lock is set at -5 and you got the ignition maps +5 around idle, then the gun is going to fire +10 versus the stock timing mark.&nbsp Remember, stock timing mark is at -5.&nbsp Also, check to see if you got some kinda ignition correction map (water temp) active that can skew the base ignition timing map.


-Ted