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Registered User
Join Date: Feb 2009
Location: Miami,Fla
Posts: 120
The numbers you are looking at are the percentage of air leaking by
1) The rings?
2) The intake valve?
3) The exhaust valve?

It is performed by pulling all the spark plugs. Then putting compressed air in the Cyl on the compression stroke or TDC ( Top Dead Center) then the little amount of air that leaks by is the % # you are reading. The engine must be cold for proper results!

Hope this helps you under stand a little better.

These numbers look good! i bought a 88 930 with 58k miles and number 2 cyl was at 45% the air was blowing right out the exhaust. i bought the car 9k cheaper then asking price and it ended up being the valve guide.
So I pulled the engine tore it down and completely upgraded to all the common mods and now it will run circles around my 89!! Night and Day!!!!

They are great stock till you drive a modified beast.
88-930 Black / Tan
89-930 Grand Prix Wht
70 Trans Am Ram Air III 4 speed
74 Bronco Sport 302 Auto Beach truck for the Mutts
Old 01-09-2010, 04:15 AM
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