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XTool, Relitive Compression Test / Power Balance Test

Discussion in 'Gen 2 Prius Technical Discussion' started by tkc100, Jul 23, 2024 at 10:29 PM.

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  1. tkc100

    tkc100 Junior Member

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    I recently viewed a YouTube review on the XTool D7 scanner. The reviewer indicated that the D7 was capable of doing a relative compression /power balance test. When I contacted Xtool I was told that the scanner can indeed do a compression/power balance test, but the 2007 Prius does not support that function. Before I even contacted XTool I questioned how that could be possible with a Prius. In the past, with other diagnostic equipment on a conventional car with a conventional starter this task was done by monitoring the fluctuation in the current draw. Since a Prius doesn't have a starter, I was wondering how this could be done and as it turns out it can't be. At least not with this particular piece of test equipment. A long time ago, once again on a conventional vehicle, with the old-style ignition system I had a test meter that would cancel one cylinder at a time and measure the RPM drop.
    I'm scratching my head wondering if a similar thing could be done on a Prius by canceling either the ignition coils or injectors. Does anyone know if there is a scan tool out there that can cancel either the ignition coils or injectors selectively? I think that the ThinkDiag can selectively cancel injectors, but I don't know if it can do that on a GEN II Prius.
    I know the shortcomings of a relative compression test, but I have used it as a go no go test.
     
    #1 tkc100, Jul 23, 2024 at 10:29 PM
  2. Tombukt2

    Tombukt2 Senior Member

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    I think the Toyota software has some kind of testing like you're talking about I don't know about dropping individual cylinders and all that I think usually a scope you do that with or you did do that with in the old days I don't know what they do now compression is too easy to check generally speaking you know you have it or you don't If it can blow your finger out of the way generally it should be able to run not necessarily well matter of fact I can't think of the last time I've even done a compression check per se even on small engines like lawn mowers and chainsaws to be honest about it I usually put my finger over the spark plug hole turn the flywheel around and see what I've got I guess after doing this for a very long time pretty good indication of what you got going on No there are no numbers but I don't need something to give me numbers per se I guess if you wanted to check cylinder to cylinder but generally speaking when things like that start to go on you're so far down the list on things wrong it's going to be interesting find out whether the people are going to fix the stuff usually not.
     
    #2 Tombukt2, Jul 24, 2024 at 10:13 AM
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