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6

You just hold the rubber ended bit against the plug hole whilst cranking the engine. No, it does not blow out of the hole due to pressure build up. This is how such a unit is designed to be used. The different designs of tube allow use on different designs of engines, choose the one which feels most appropriate to the vehicle you are testing.


4

There is no such thing as an octane sensor. Octane is analyzed in two ways. Analysis of the chemical composition, they call this Research. They place the fuel into a test engine and run it until it pings, they call this Motor. If you look at a gas pump it will usually show for example, 87 octane (R + M)/2. This is an average of Research and Motor. A modern ...


4

Yes it can. The reason is, these are two different tests, done differently, reading different things. To understand this, you need to understand how the tool works for each test. For the compression test, the test apparatus captures and holds the compression as it builds through several, but counted revolutions of the crankshaft. You will get so much ...


3

You asked What do these compression figures mean Response Not that much when the engine is cold. Background Based upon the information you have provided I see no indication that the rigs are bad. You aren't burning any oil You do not have oily carbon buildup on your spark plugs Bad rings will almost always give you those two symptoms, if they ...


2

Rings generally wear at the same rate meaning that when it's time to replace one you should be replacing them all as they're not seating with the cylinder properly any more. Burning oil does not always imply a loss of compression. Cars with good rings will burn oil due to bad valve guides or bad valve guide seals. A compression test should help you ...


2

As far as I'm aware, it cannot be done. Vacuum is a direct relation to valve lift and timing, does not relate to compression ratio. The vacuum is drawn during the intake stroke. In a 4-stroke (cycle) engine, the intake and compression events are completely separate.


2

Your piston rings are worn. This is allowing oil into the combustion chamber so it's being burnt off... Typically accompanied by a sweetish smelling exhaust and heavy gas smell in oil itself. And the reason you didn't need to step on the gas when the compression was checked is because the spark plugs shouldn't of been working... This it wouldn't have helped ...


2

One pump; one pump only. Which test we perform determines the procedure used. Three procedures are described and each test has a different purpose. But keep in mind when the engine is running it only gets one pump per cycle. Running compression test: A decent way to estimate volumetric efficiency (VE). This is not technically a compression test. Install ...


1

From the looks of it, you're going about your compression test incorrectly. You should rotate the engine, using the starter, for the same number of revolutions with each cylinder. This will give you a truer tale of what's going on. Usually 4-5 revolutions gets the job done. The reason you want the same amount of revolutions for each cylinder is so the tests ...



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