Cylinder balance test - how to interpret it?

[2000ssnb]

I palyed around with the cylinder balance test and am not sure
what to do with the results. I set the rpm to 950 rpm before
running the test (other test conditions required were met) .
Then I ran the balance test and did get the bar chart. Within each bar
there was an individual rpm number. These numbers varied for each cylinder
from about 893 rpm to 945 rpm from lowest to highest value.

My question is that I now know "the weakest and the strongest"
cylinders but I don't know what range is okay. All I know that
the rpms of each cylinders must be the same since they are all hooked
to the same rotating crankshaft. How does this "unbalance rpm" number relate to the compression etc.?

Thanks,

Gertr

[Blacky]

The numbers should all be "similar". There is no exact right and wrong.
The test shows the relative "performance" of each cylinder. The absolute values are not important, the difference between the numbers is important.

The purpose of the test is to discover which cylinder is contributing least to the power output of the engine.
That cylinder should be the first cylinder that you "check" by conventional means. i.e. compression test, check injector, check plugs etc.

Regards
Paul

[emarkay]

It's kind of like in the "good old days' when you would run a compression check on each cylinder. It's not the same thing, but the results indicate similar situations... A cylinder (or more - eek!) that is not producing the same as the others.

This also measures injector function (relatively) as well as mechanical compression and ignition preformance, all due to the sophisticated misfire diagnostics built into these engines.

MRK