if i un plugged the est lead tan and black wire lead would it cause the engine check light to come ,i plugged it back in now to check if light goes out but my batt has died now ,so i carnt check at the moment

 

Yes, unplugging the EST wire will cause check engine light. Disconnect battery to clear code. Your dead battery probably isn't dead "enough" to clear code (ha, ha).

 

I believe so. If battery went completely dead or you disconnected the battery it would remove any stored codes anyway. So, just charge it up and see. By the way, unplugging the timing wire just removes the ECM from making any timing changes, unhooked it would revert back to whatever intial timing is set on your car. usually 6 degrees BTDC on a 350 map engine. You don't "hurt" anything by unplugging it. you wouldn't want to drive it that way though.

 

LOL I took too long typing.

 

cheers guys