Compression Test
 

How should I do a compression test on a 86 951? My dad is taking the car for a test drive for me and I thought maybe he should do a compression test before I buy it. Can somebody give me some step by step instructions I can send to my dad? I did a search but didn't find exact procedure. Thanks.

Compression Test Procedure
 

Here you go dude:
1: Make sure car has a healthy battery, and engine is warmed up.
2: Unplug fuel pump fuse and run car until it stalls, this will clear the fuel rail, leave fuse out for remainder of test
3: Block throttle plate wide open with a screwdriver.
4: Remove the plugs and air cleaner (preferably)
5: Insert compression guage into corresponding cylinder*
6: Crank engine over until guage shows no further rise, usually 4 or 5 compression strokes.
7: Record readings as you go for comparison, the lowest cylinder shouldn't read 10-15% below the highest cylinder.

*Make absolutely sure that the compression guage fitting is the same length as the spark plug threads!

You may also want to have a battery charger hooked up between readings. The starter will turn slower and slower with each crank. My Interstate battery was gasping for breath by the time I got to my final pull! ;_0