Adjusting the timing on a Geo Metro takes specialized tools and a clear understanding of engine mechanics. Making adjustments to the Geo Metro ignition timing is required when installing many aftermarket performance parts, or after changing the timing chain. Adjusting the timing on a Geo Metro properly increases gas mileage and lowers emissions.
Start the Geo Metro engine and allow it to idle until it reaches normal operating temperature. Turn the engine off, leaving the ignition in the "On" position for five seconds, then restart the car. Run the engine at 2,000 RPM for 5 minutes then let it idle.
Turn off all accessories such as the radio, air conditioning and lights. Place the transmission in "Park" or "Neutral" and set the parking brake.
Connect the tachometer to the negative side of the ignition coil. Attach the timing light to the battery and then into the number one ignition wire on the front or far right side of the engine.
Remove the cap from the diagnostic connector next to the ignition coil and jump the lower two terminals with a number 4 terminal connector. Aim the timing light at the timing marks on the crankshaft pulley.
Loosen the distributor mounting bolts and turn the distributor until the crankshaft timing light matches the center mark in the timing gun. Tighten the distributor mounting bolts and recheck the timing. Remove the number 4 connector and replace the cap.
