I need to do a compression test to confirm I am having a head gasket issue can anyone direct me on how to do this. I bought a kit from the auto parts shop but I want to make sure I know step bby step how to conduct the test.

 

This is how I would do it, not to be confused with professional advice:

Remove what you have to in order to get to the spark plugs.

Remove the spark plugs.

Screw in the test gauge. Don't worry about getting it tight as there is an 'O' ring to seal the connection. Getting it too tight can result in the hose to spark plug connection turning rather than unscrewing at the bottom of a 6" hole. This will result in extended profanity. Ask me how I know.

Hold the throttle pedal to the floor, hard. That cuts off fuel and opens the throttle plate. After typing that I realized that I did not have a clue as to what happens to the fly-by-wire throttle plate when the fuel disable feature is used.

or

Remove the air filter to throttle body duct

Install a large screwdriver into the throttle body, handle first to hold open the throttle plate.

With the throttle pedal held firmly to the floor crank the engine for about 10 seconds.

Read the gauge.

Record the reading and move to the next cylinder.

 

Hold the pedal to the floor, then turn on the engine??

Why would you bother messing with the throttle body?

 

You need the throttle wide open in order to allow as much air as possible into the cylinder so giving the maximum compression.

When the throttle is closed no air flows into the cylinder so compression is zero.

 

Pulling the Fuel Pump Relay removes all risk of squirting fuel into the bores.



Still need to floor the pedal whilst cranking.

Graham