Probably a bit of a basic question, but I have seen many slight variants in compression testing on t web
ie all plugs out, just one plug out, WOT, disconnect fuel pump etc
I have a zetec with fuel injection and I know I have to disable the spark, but do I disable fuel pump as well?
and I was going to go for all plugs out and do one cylinder at a time.
What are your thoughts please.

Andi

no straight answer depends on what you suspect is the problem ie : rings - valves
for a general check
all spark plugs out , allows quicker turn over and less drain on the battery
disconnect the spark and petrol for safety
if you suspect rings not valves post again.

Warm engine
All plugs out
Disable fuel pump, especially if FI
Crank 1/2 dozen turns with wide open throttle
If readings are low then squirt oil down bores to see if they improve. If they do then suspect rings.
Job done

What you are aiming for is to make the test as consistent as possible. Same amount of engine drag, same throttle opening and same length of cranking etc.

As said before fuel and sparks are disconnected for safety.

Compression tests need to be done with "wot" wide open throttle

personly I always do mine with all 4 plugs out and just spin the starter 3 seconds

Steve