MrEvo9Mong

Did my compression test today got some pretty low numbers now i know it should be 155-180 +\- 15 and consistent between all four cylinders, but im reading mix reviews on here that as long as its +\-15 of eachother its fine and if the head is cammed its normal and some says its not and so forth, so wtf am i looking for exactly? This was done on a dry test 45min after the car was shut off

C1: 100
C2: 100
C3: 92
C4: 110
(Note: i did the test twice and same result)

Now am i ****ed or am i good? Lol

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4b11slayer

Definatley low numbers.
How many times did the engine spin when doing the test? If you crank it longer does the max psi stay the same?

Next order of biz is to do a leak down test. See were the compression is being lost. I.e rings,valves,head gasket.

MrEvo9Mong

6-8 times each cylinder and wont go past the psi as stated above, should i try a wet test first before leak test?

4b11slayer

Wet test it. If it rises its likely a ring issue.

Is the car using oil?

MrEvo9Mong

By using do you mean burning? If that than no it doesnt

4b11slayer

Yes burning. Hmm usually bad rings burn oil.

Do a leak down, report back.

Note: you gotta do leak down test on tdc compression stroke.

MrEvo9Mong

Ok what percentage should i be looking for? 10%? 15%?

4b11slayer

%5.

The percentage shouldnt matter at this point, you just need to find out where its leaking to repair it.

RightSaid fred

Photos of spark plugs?

Bacek88

the only thing I would also suggest is trying a different tester. With the numbers being more or less even across the board I think your tester may not be reading accurately

MrEvo9Mong

Yea same result but my tester is brand new from the store and the sencond tester is from oreilly which was really ****ty cause of the leakage at the connection, so gonna have it leak down test it today. Will post results.

MrEvo9Mong

Dont have any at the moment but they look pretty good but ill take some for you when i perform the leak down test

MrEvo9Mong

Results!

So after a day of testing, come to find out that my rings are bad. Wet test demosntrated a increase ammount of 15-20 psi per cyclinder with cylinder 4 at highest.

Wet Test:
C1: 132
C2: 138
C3: 140
C4: 148

Leak-Down Test:

C1 - 75%
C2 - 15%
C3 - 5%
C4 - 5%

4b11slayer

Your sure you were at true tdc on compression during the leak down test?

Crank pulley tdc is only good for cylinder 1 then the rest need to be set to tdc with a screwdriver in cylinder till tdc and has to be compression? Was the leak down coming from dipstick or oil cap?

MrEvo9Mong

We did them all with a long extension to set tdc on all four cylinders, and if you meant by air escaping we didnt bother to listen for air and went straight to the wet test cause the leak down test was different from the dry test (i tried a new comp tester and got C1: 110 C2: 110 C3: 120 C4: 115) so thats when we went for the wet test