Compression Test results

[rruddfan21]

hello all. i did a compression test on my 91 geo metro today and here are the results.
MINIMUM COMPRESSION ACCEPTED VALUE: 156.4

my results:
CYLINDER #1: 180 normal
CYLINDER #2: 120 low
CYLINDER #3: 154 low (barely)

i think it may be blown head gasket, but not too sure. what do these results mean? thanks in advance.

corey coby

[capritoms]

It appears to me to mean that you might as well cut the plug wire for number 2 because it isn't really doing anything anyway.

[frets14]

Originally Posted by rruddfan21

hello all. i did a compression test on my 91 geo metro today and here are the results.
MINIMUM COMPRESSION ACCEPTED VALUE: 156.4

my results:
CYLINDER #1: 180 normal
CYLINDER #2: 120 low
CYLINDER #3: 154 low (barely)

i think it may be blown head gasket, but not too sure. what do these results mean? thanks in advance.

corey coby

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Granted that cylinders 2 & 3 are on the low side and it's an indication of a future problem (probably a valve job at a later date), However, I think the cylinders should still POP when the spark hits them. I've got a 95 Metro to work on that has only 30 psi in 2 cylinders and once they get hot enough they all will pop. I also don't think you've got a blown head gasket. My guess would be either a clogged converter or the engine has jumped timing. To isolate the cause of your low compression, squirt some oil in the cylinder before you check it. If the compression goes up with the oil in it, then you've got worn rings. If it stays the same, then your valves are not seating tight. Good luck!