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Discussion Starter #1
I just did a compression test on my car and each cylinder was about 120psi. I saw in another post that 150psi was the minimum. This is a 96, with only 67,000 miles on it. It doesn't burn oil. I squirted a little oil in a couple of cylinders to see if the compression would go up and it didn't.

Is this really a problem? Should I be worried? Has anyone ever seen compression this low?
 

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Senior Member
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Your best bet would be to PM shawn..... ask him and he can help you out.....oh and this one belongs in the engine performance forum
 

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missing El Polo Loco...
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^^compression testing is not a really accurate method of acknowledging the block's condition. Leak down test is a bit more helpful in determining what could probably did what. Otehrwise, tearing into the engine is the absolute.

Anyway, about your reading, 120psi @67k is not normal at all. Check if the gauge is deffective.
Try get another compression test gauge, they're only $24.99 at Sears right now (plus some 4% discount where I live). Chances are yours is broken like my old one.

Any recent power loss?
 

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I just checked my FSM and if I am reading this correctly then the standard compression pressure is 178 psi.......the minimum is 149 psi....so then your car is either way off or like ashura said, your pressure gage could be busted.
 

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Do A Leak Down Test on it.:)
 

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missing El Polo Loco...
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3 seconds is too short. the engine won't even reach it's TDC by then. The main idea of compression testing is to see how much pressure the block can build up. If the interval is too short, then the engine won't have any chance to build up pressure in the first place. 10 seconds. Count it like one-one thousand, two-two thousand, and so on till you get to ten-ten thousand.
 

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Die Trying
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i always did mine at 5 rotations, usually about 5-6 sec total.
but yeah, those numbers seem a little low if those are the true numbers. I always got 160-170 on mine. Well, now they read 80, 0, 0, 0. Not good.

good luck and do a leak down test
 

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missing El Polo Loco...
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mine: 1, 2, 3, 4
dry: 170psi, 175psi, 170psi, 170psi
wet(1 cap-full of Penzoil quart bottle cap): 195psi, 195psi, 190psi, 180psi

that's an 11yrs old block w/ over 220K miles on it, abused for the last 4yrs.

my first compression gauge only lasted 7yrs..wonder how such a simple device could ever fail. I'm on the second one now. I think my first one was a sun-pro unit. and 7yrs is quite long now that i think about it. This new unit I got from sears (forgot the brand) appears to be of better quality, but who cares, compression gauge is compression gauge.

When you got 0psi with a wet test after getting 120psi "dry", then something definitely is very wrong with the gauge, because in order to even fire up, an engine needs at least 80psi. And in my situation, the gauge was faulty as the engine fired up later on.
How did Nissan figured 149psi as the service limit is beyond me.

And my leak-down test result were as following:
1, 2, 3, 4:
Loses @ 80psi @ each cylinder's TDC: 7psi, 7psi, 7psi, 10psi
 

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Erect Member
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i usually just crank until the number goes no higher. about 5-7 seconds, about the same as ryan said...
 

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Got HAULIN' ASS?
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compression testing

To properly complete a compression test, you need to count from one to four, somewhat slowly, in doing this it will give the maximum pressure that particular cylinder will produce.
If you turn the engine over for 10 seconds it will give you inaccurate results. Just remember count 1 - 2 - 3 - 4, and it will give the true pressure.
 

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I'm The Green Member
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travis is the most accurate, since the engine itself is a 4 cycle engine you are only suppose to let it go through all 4 cycles once. if you do any mor or less you will get inaccurate results.
 

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I bought another compression tester and here are the results:
Cyl. dry w/oil
1 142 149
2 141 150
3 149 154
4 141 149

This kind of annoys me since the engine only has 68K miles on it and the minimum compression is 150psi.
 

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missing El Polo Loco...
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ok...like what did you did to it? that's really low, for evena 68K engine..does cranking longer get the numbers higher?

when it cranks, does it crank good? a weak starter will give you low numbers.
 

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altima/dsm lover4life
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We are making this simple issue into something hard if the compression is low then it is low don't throw in the starter or compression gauge being bad it just confuses things. Even after getting a new gauge it still gave similar readings. So the point is you need to rering it more than likely. The reason why the compression rises when you add oil is b/c the oil is helping the rings seat which is turn raises the compression when you do a wet compression test. So you need to rering it but while you have it apart look over the head and valves for any other problems. So there you go problem diagnosed now u have to fix it.
 
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