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7

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.


6

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 ...


5

Those numbers do not seem horrible, unless the 140psi is low. You might want to repeat the test with the engine warm. I generally feel that a cold test only reveals inter-cylinder differnces (in your worst case only 18psi), but dynamic compression after everything is warmed up and expanded might be much better.


5

Yes, it does lead to a loss of a power, but your compression is not worth worrying about. Every engine will loose some compression after a few years. New rings wear out faster at the beginning and later they wears out slowly, so probably you won't see a difference for another 2 years.


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 ...


3

Background The Corsa has dual overhead cams. The cam rides directly on a bucket that sites above the valve stem and valve spring. In order to adjust your valves you have to properly size shims that sit between the bucket and the valve stem. Over time, the valve face, in the combustion chamber, gets worn into the valve seat. As valve clearance is taken ...


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 ...


2

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 ...


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

TL;DR: Either there's a problem with the head gasket, or with the piston rings. Remember, the piston rings fly over the openings in the cylinder wall, and there's no radial force onto the section exposed to the opening, pushing it into its groove. Shortly after, this section touches the cylinder wall again and experiences the radial force pushing it back. ...


1

I did some searching on IATN and found known good pressure waveforms that are identical to my after repair captures. Unfortunately I can't post them here. It turns out that hump is completely normal. After doing more captures on different cars with VVT I've found that most waveforms are unique to some degree. I guess the same can be said about non VVT ...



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