quote:

ORIGINAL: NoBrakes

I am no expert but try this. And good luck

Interpreting Compression Test Results If all cylinders are performing equally and engine performance is acceptable, the engine passes the test.

Variations in compression between cylinders should be no more than 20%.

When two cylinders next to each other have low compression, a blown head gasket is usually indicated.

A blown head gasket.

One or several cylinders with low compression and no apparent pattern of loss often indicates burned exhaust valves.

Rough idling is a symptom.

At higher rpm, the rough running from the burned valves disappears.

NOTE

On an engine at idle, a burned exhaust valve will cause a dollar bill to be sucked against the end of the exhaust pipe every time the bad cylinder's piston has an intake stroke.
Wet Compression Test If any cylinders auto body part show poor results, perform a wet compression test.

Squirt about a tablespoon of oil into each low cylinder.

The oil makes a seal around worn rings, boosting the compression reading.

When cylinder readings that were low increase to normal during a wet test, a piston ring problem is indicated.

NOTE

Adding too much oil takes up volume and raises compression. When the compression test is completed, install the spark plugs. Be especially careful not to strip the threads on an aluminum cylinder head and use anti-seize compound on the spark plug threads. To more accurately diagnose engine problems, use a cylinder leakage tester to perform a cylinder leakage test on the engine.

NOTE

A compression test will not tell the condition of oil control rings, only compression rings.