S15/T15 Sonoma P/U 2WD L4-2.2L VIN 5 Flex Fuel (2001)
Compression Check: Testing and Inspection
Engine Compression Test
Perform the following steps in order to conduct a compression test for VIN 4:
1. Conduct the following steps in order to check cylinder compression:
1.1 Engine should be at room temperature.
1.2 Disconnect wiring from the ignition module.
1.3 Remove the spark plugs
1.4 Throttle body valve should be wide open.
1.5 Battery should be at or near full charge.
2. For each cylinder, crank engine through four compression strokes.
3. The lowest reading cylinder should not be less than 70 percent of the highest.
4. No cylinder reading should be less than 689 kPa (100 psi).
Important: The results of a compression test will fall into the following categories:
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Normal -- Compression builds up quickly and evenly to specified compression on each cylinder.
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Piston Rings -- Compression low on first stroke. Tends to build up on following strokes but does not reach normal. Improves considerably with
addition of oil.
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Valves -- Compression low on first stroke. Does not tend to build up on the following strokes. Does not improve much with addition of oil. Use
approximately three squirts from a plunger-type oiler.
