How to do a compression test??

[racerboymx]

Well lads tried doing a search there but could not find an exact method or best technique for doing a compression test on my 4EFTE ??? I know the basic method and I have a compression tester but just when i was driving the car this morning and when i came off the throttle I seen a nasty puff of smoke behind me so want to do a compression test to make sure my rings are alright Cheers derrick

 

[GTdan]

warm engine.

take plugs lead off
unplug the injector harness goign to each injector
crank over on each cylinder for 5 seconds on WOT

 

[350ep70gr]

In hot engine (operating temp) you take off the spark plug and fit your tester.
Then you cranking the engine for a few seconds (lets say 10 or till the testers stops growing) with the throtle full open. Before cranking starts, pull the king lead or/and efi fuse so you have no spark /fuel dilivery.
Repet it in all cylinders. Standard comp is at about 180-185 psi for a fresh good engine.

Chris

 

[racerboymx]

Thanks lads just wanted to be 100 cement sure rep added

 

[gorganl2000]

please note
results will vary slightly with the instrument used

also, results may vary a little between the 4 cylinders....but they should be close.........a variance of 5% - 10% is usually acceptable

if your engine is not a healthy stock built one...u may see different figures from the above----things like low compression pistons, head chamber work, thicker head gasket, etc. can cause this

so just bare those thing in mind

 

[350ep70gr]

please note
results will vary slightly with the instrument used

also, results may vary a little between the 4 cylinders....but they should be close.........a variance of 5% - 10% is usually acceptable

if your engine is not a healthy stock built one...u may see different figures from the above----things like low compression pistons, head chamber work, thicker head gasket, etc. can cause this

so just bare those thing in mind

^^^^ 100% spot on. All the mods that the engine carys can effect comp with one or the other way.

Chris