Where is the number one on distributor cap in a 1987 Cadillac fleetwood 4.1 liter engine?

There's no universally consistent "number one" marking on distributor caps across all 1987 Cadillac Fleetwood 4.1L engines. The location of #1 cylinder on the distributor cap depends on the specific engine's firing order and the distributor's orientation within the engine bay.

To find #1:

1. Consult a repair manual: A factory service manual or a reputable aftermarket repair manual specific to your 1987 Cadillac Fleetwood 4.1L will show you a diagram of the distributor cap with the correct firing order clearly marked. This is the most reliable method.

2. Use the firing order: Find the firing order for your specific engine (it's often listed on a sticker under the hood or in the owner's manual). The firing order tells you the sequence in which the cylinders fire. Knowing this, and visually tracing the distributor cap's wiring from the spark plug wires to the cap terminals, you can deduce which terminal is #1.

3. Visual inspection (less reliable): Some distributor caps *might* have a subtle marking indicating #1, but this isn't guaranteed.

In short: Don't rely on guesswork. Using a repair manual specific to your vehicle is the only sure way to correctly identify cylinder #1 on the distributor cap.