I'm trying to do a tune-up on my 1995 Toyota 4Runner with the 3.0L V6. Which pins on the diagnostic connector do you short to set base timing?
Let's go through the procedure so everyone knows what we're talking about. "Base timing" is when the ECM's (Engine Control Module) electronic spark timing control is disabled, so that the ignition timing's origination point may be set by adjusting the position of the distributer housing.
Start with the engine at normal operating temperature, transmission in park or neutral, the A/C and coolant fan off, and idle speed between 750-850 rpm. Then we hook up the timing light to Cylinder #1 plug wire which is located at the front of the right cylinder head. Now we locate the DLC (Data Link Connector) on the right side of the engine compartment.
When looking straight at the 17 pin connector with the group of nine terminals at the top, terminal TE1 is dead center and terminal E1 is in the lower right corner of the group of nine terminals. By connecting these circuits with a jumper wire we have placed the system in base timing mode.
Now point the timing light at the engine's front cover and observe the mark. It should be right at 10 degrees BTDC (Before Top Dead Center). If not, make the correction at the distributer. Once base timing is set remove the jumper from the DLC connector and again observe the timing mark. It will now be electronically controlled by the ECM and a reading of 8 degrees will confirm proper operation.