2011 North American V-8 compression test- help needed.

[Shoshone]

My 5.0 non supercharged started missing on a grade. Engine sounded rattly, found cylinder 7 missing on scan. 118K miles.

The timing chain had not been making any bad sounds up til then. The engine actually sounds ok now, except for the miss on number 7.

I would like to do compression and a bore check on 7. I can't find what relays/fuses need to be pulled to disable the fuel and ignition. All those pages in the manual isn't helping. Hopefully someone here can.

 

[Rover Range]

Fuel pump relay and fuse are in the engine compartment fuse box.
Relay R103
Fuse F6 25A

 

[Shoshone]

Thanks. I'll let you know what I find.

 

[Shoshone]

Fuel pump relay and fuse are in the engine compartment fuse box.
Relay R103
Fuse F6 25A

Thanks. I'll let you know what I find.e

I could not find relay R103. Here are pictures of the underhood fuse box.

 

[Rover Range]

 R6 Would be the fuel pump relay.
Keep in mind, takes forever to burn off the fuel in lines.

 

[Shoshone]

Well, this was not what I expected. The compression was over 180. The bore scope showed no damage I could see. Almost by accident I found this. The electrode gap was about .080, and the insulator had broken and was covering the center electrode. All plugs were worn like this. I installed them about 7,000 miles ago. I replaced all the plugs, and the engine now runs smoothly and about as quiet as these engines can.