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<p><b>acr writes: </b></p>

<p>Is there any how to's? I've never done it before and the FSM is little light on that subject. Any thing I should worry about? </p>

<p><b>mario99ACR writes: </b></p>

<p>Get a compression gage. Warm up the engine. Disconnect the coil. Take out all the plugs. Screw in the gage. Open up the gas all the way. Crank motor. Read gage. Repeat 3 times. The goal is to be within 10% of each. I believe. I'm not sure what is the low limit. Maybe 100 lbs.?</p>

<p><b>Greg Smith adds: </b><p>

<p>Supposedly engineering is more comfortable with the "no less than 100 psi and max variation of 25%" line which is in the compression test procedure. </p>

<p>One more thing: You really should pull the ASD relay when compression testing instead of disconnecting the coil. Pulling the ASD relay disables the spark *and* the fuel by removing the power source for the coil and the injectors. The fuel injected each time you crank the engine is washing down the bores, which can make the compression readings abnormally decrease from the first to the last cylinder tested. There is no need to ground any coil wires when pulling the ASD relay.</p>

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