08 Boxster Compression Test

[Vza]

Hi All, Going to do a compression test on my newly acquired 08 Box. Just want to be sure of the procedure:
Eng to operating temp
Pull all coil packs and plugs
Pull Fuel pump fuse
Disable Ignitions Sys(not sure how)
Attach Comp.gauge
Throttle to the floor Crank 5 or so times
Repeat for other cylinders then repeat with squirt of oil in each

Just not sure how or why to disable ignition sys when all the coils are removed anyway. Can I just un plug the DME in the trunk to do this? Did it before can't remember.

Thanks V

[blue62]

Originally Posted by Vza

Hi All, Going to do a compression test on my newly acquired 08 Box. Just want to be sure of the procedure:
Eng to operating temp
Pull all coil packs and plugs
Pull Fuel pump fuse
Disable Ignitions Sys(not sure how)
Attach Comp.gauge
Throttle to the floor Crank 5 or so times
Repeat for other cylinders then repeat with squirt of oil in each

Just not sure how or why to disable ignition sys when all the coils are removed anyway. Can I just un plug the DME in the trunk to do this? Did it before can't remember.

Thanks V

When you crank the engine over for the test, crank it for a timed period for each cyl.
Say 5 seconds each cyl. trying to count crank revolutions is very difficult.
Also have a charger on the battery so you have as equal cranking power for each cyl. as possible.
Equal cranking power and equal cranking time for each cyl. is important in how it relates to balance of power from one cyl. to the next.

I don't have info on electrical layout of an 2008 so can't help with disabling ignition system.

The rest of your planned procedure looks good.

[Vza]

Thanks...Anyone want to chime in on disabling the ignition sys. Or just unplugging the DME will do it? Thanks V

[Stl-986]

Why do you need or want to? If you are just checking compression all you need to do is remove the plug & fuel pump fuse, crank it over for a set amount of time, then move on to the next cyl. Dont need to make it more complicated.

[Vza]

Thats what I thought. Just wanted to be sure.