The distributor cap's rotor will point to cylinder #1 when the engine is at Top Dead Center (TDC) on the compression stroke of #1. To find #1:
1. Locate #1 Cylinder: The #1 cylinder is typically the front passenger-side cylinder. You might find a casting mark on the block or the engine valley cover indicating it's location. Consult a repair manual or a reliable online resource with diagrams for your specific engine for the most accurate identification.
2. Verify TDC: With the engine at #1 TDC, the rotor should point to the #1 terminal on the distributor cap. If not, you may need to carefully rotate the engine a full 360 degrees to double-check. A compression tester or a piston stop tool can be incredibly helpful here to confirm the piston is at its highest point.
Important Note: Always refer to a service manual specific to your year and model vehicle for the most accurate information. There are slight variations possible depending on options and manufacturing tolerances. Improper firing order can cause severe engine damage.
