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General => The garage => Topic started by: the_GTI_new_guy on 09 June 2005, 23:55

Title: How to perform a compression test?
Post by: the_GTI_new_guy on 09 June 2005, 23:55
Got me a compression tester. (Just a cheap thing from ebay but should be fine) No instructions with it though. Can someone give me instruction on what to do with it? I think i know what to do but dont want to bugger it up. My guess would be remove plug to be tested. Screw in meter, Remove middle ht lead at coil to stop spark. Turn engine over for a few times (about half douzen i gues, just till reading stabilises) Repeat on other cylinders.
Just say spot on and i am happy man.  :smiley:
Cheers guys
Title: Re: How to perform a compression test?
Post by: Mr Blue on 10 June 2005, 00:45
Think you hold the throttle fully open.

As long as the readings are roughly the same then thats fine.
Just take out all the spark plugs to speed things up a little. Make sure you cover the holes with some cloth or you will get sh!t in your face :laugh:

In a wet compression test you put a few drops of oil down the spark plug hole and then do the compression test. Cant remember the reason why they do that coz im f**king tired and its 12:43am :grin:
Title: Re: How to perform a compression test?
Post by: richandhazel on 10 June 2005, 00:49
yes thats basicaly it. As long as the readings are roughly the same then thats fine.
I just take out all the spark plugs to speed things up a little. Make sure you cover the holes with some cloth or you will get sh!t in your face :laugh:

In a wet compression test you put a few drops of oil down the spark plug hole and then do the compression test. Cant remember the reason why they do that coz im f**king tired and its 12:43am :grin:

Doing a dry and then wet test helps to identify cause of loss of compression. If compression increases dramatically with wet test then rings are worn.