Is it possible to get higher numbers when doing one cylinder at a time?.. ie leaving other 3 plugs in while testing cylinder.

Reason for asking

did my compression test today and a freinds

my freinds car we got low numbers on his 3 cyl so we just said o well

When later putting the plugs back in we decided to check the 3 cyl again..

I noticed the engine turned faster with the other 3 plugs in and we got a higher number. No coils werent hooked up or even on the plugs. it was 127 all plugs out and then 220 with 3 in?
His others were all in the low 230's
Any ideas. I Do know no matter how high you rev your compression in the cyl is always the same..

 

redo test after a good drive so car is warm, take all plugs out, take fuel fuse out, crank a solid 6-7 times max per cylinder, and also be sure to keep youtr gas pedla to the carpet (floor)



done

 

all plugs in or out should not matter as each cylinder is independent of each other, but be sure to remove them as it is part of the correct procedure

 

As siad above

Do it with all plugs out,

 

quoted for the troof.
Theres a reason for taking all your plugs out.. i forget what.

minimal deviations between cylinder pressures are o-k.