Quote:
Originally Posted by Elias_E90
Quote:
Originally Posted by rjahl
Just a question, do you need to lock the VVL open to get a reliable compression check?
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I dont think so, because the compression occurs when the valves are closed -> no lift. The tool (pressure gauge) will hold the maximum pressure when you crank for 4 cycles and should be the same pressure for all cylinders
I think you only need to disconnect fuel pump (fuse/relay) and disconnect coil packs, remove the plug and put the tool and cranck for each cylinder |
If you are cranking with the ignition key, ok perhaps the intake valves probably lift enough to get good cylinder filling. I've never logged the Valvetronic motor during the start.
If you are bumping the starter only, I'm not sure the intake valve will open far enough to allow proper cylinder filling. No air in, no compression pressure.
Just like the old days when you had to open the throttle or throttle body to perform a compression test.
Have you done a compression test on a valvetronic motor? I'm curious to hear from some one who has.