Relative compression test using the Snap-On Verus. You do not need a Snap-on scope to do these tests. The same procedure can be followed using any Lab Scope.

Engine Performance Diagnostics chapter 1 pages 17-22

test shown enh 50

  • how to use starter current to determine cylinder compression
  • how to synchronize the starter current pattern with an ignition firing event to determine exact cylinder location

Tools used

  • lab scope
  • low amp probe
  • high amp probe (preferred)
  • secondary ignition pick-up

end faq

Playlist

(Chapter 1) Misfire ID, Compression Test, Vacuum Leaks, Fuel Trim, Head Gasket, Restricted Exhaust, Low Power, DMM

Related videos:

How to perform a compression test with a scope (Picoscope):

Relative Compression Testing Variables (3 cylinders have no compression):

How to check for a jumped timing chain or belt:

end faq


For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available as an eBook or paper book.

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