BD said:I followed these instructions for a compression check (it was good btw) but I'm just curious why the ignition system has to be disabled (the fuel system makes sense to me) because if all the plugs are out then why does it matter? The only reason I ask is that I'd like to avoid taking the cap and rotor off to take the leads off the ignition coil.
And if it is imperative to disable the ignition system, couldn't you remove a fuse or something instead? Thanks.
what kind of car are you testing?
you dont want the electricity from the plug wires arcing everywhere and frying things.