08 Boxster Compression Test

[vza]

Hi All, Going to do a compression test on my newly acquired 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

[deilenberger]

The DME is likely needed to run the starter motor.  I wouldn't be concerned about power if the coils are disconnected.  Most electronic ignition systems use a constant + feed to the coil, switching the ground to complete the circuit.  That means there is no electronic pulse going to the coil connectors when the coil is fired, so disconnecting them should  be quite safe. You can expect to have a bunch of stored error codes when you're done, but they should clear just fine if you have even a basic OBD-II tool.

 

BTW - you posted this in the convertible top troubleshooting forum, which might account for the lack of replies (besides the generally ghost-town status of this forum.)

[vza]

Ok thanks ...thats what I was thinking...no issue if coils are removed anyway. V