My timing moves a couple of degrees to 10 when I ground the TEN terminal but still advances when the RPM goes up. Is it supposed to lock all the way up the RPM range? Car is a 96' if it matters.

Dave

 

In my understanding that is normal.
Grounding the TEN connector blocks the effect some engine sensors have on timing so you are left with the uncorrected timing map.
(Narrow band corrections, temperature sensors, knock sensors etc are ignored.)
This map will still change with rpm so usually idle is set with screw on TB to 850 when checking timing.

 

Thanks for the reply. I'm going to check a couple of other OBD2 cars as well.

 

if gnd/ten is jumped, the timing will lock at 10° throughout the revs.

 

So it is possible to set timing at any rpm?

On my car 99 10AE (OBD1) timing advances with increased rpm when gnd/ten is jumped.

 

it is supposed to stay locked, but it's possible the ecu advances it with rpms as a failsafe in case of forgetful nancys.

 

M
Mine moves but wont lock. I have a pretty sweet Ferret advance timing light and the timing advances very nice and comes in quick. My original CAS had timing right at 10the degrees. In any event I will check our spec car to be sure.