How do you turn off fuel to do a COMPRESSION TEST?

[96743explorer]

My 2006 V6 Exploder is throwing a code that is a missfire in cylinder 5. Truck recently overheated due to a bad thermostat. other than that plugs, wire, and coil was changed last year. After i replaced that the truck ran fine for a month or so. I tried switching the wires on 5 and 6 from the plugs to the coil pack and the missfire stayed at 5. Im hoping for a bad injector at most as i dont want to pay for something bigger. I have a compression tester that i want to do but need to cut off the fuel to use it. How do you do that? Pull relay #9 and run the truck till it shuts off?

 

[NickStorey]

Under the passenger side glovebox I believe theres a fuel reset toggle, not sure if that will do what youre looking for?

 

[shucker1]

Not sure if #9 is the correct relay on an 06'.

Pulling the fuel pump relay will prevent it from coming on.

You can drain any left over fuel pressure off of the fuel rail by depressing the schrader valve on the fuel pressure test port test port if it has one.

Or like you said crank it up without the relay and it should start up sputter and die from lack of fuel.

I would suggest removing all plugs before compression test and keeping the throttle plate wide open so you get good results.

 

[96743explorer]

Thanks for the info guys. Since pulling #9 relay did nothing, I ended up unplugging the coil pack. Got 180 psi of pressure in all cylinders. Found out the problem was the coil pack. Even though it was changed out last year, I found a crack on it near the #6 port. Weird cause the the code was for the #5 cylinder. Thanks again guys for the time and input.