Compression to low?

[1995 brian]

I just did a compression test on a 97 gsx and it came out 120 all around and that was a dry test didnt have time for the wet test. (Got dark on me) but im pretty worried because i read that 164psi is a good number anything under that is low.
Any predictions on what could be going on?

 

[92AWDHX40]

Why does that concern seems ok are you overheating at all any concerns buring oil? Does the car start, have you done a test drive? Is it something you want to buy, how about maintenance on the car or any documentation?

 

[mcrae_06]

How to do a Compression Test

DSMtuners.com Tech writeup on how to perform a compression test.

Let me google that for you

-hope this helps

 

[1995 brian]

It was my ex car and no overheating and no oil consumption just the numbers seemed low thats all.

 

[pauleyman]

Was the car warm? Did you read the links?

 

[1995 brian]

Yea it was and yes i did thanks for the links by the way

 

[pauleyman]

Sounds like it's time to perform a leakdown test.

 

[mcrae_06]

Found a pretty good writeup, thought it might be useful.

Leak-Down Test Procedure

1. Remove the spark plugs and rotate the engine to put the cylinder to be tested at top dead center. Tip: insert a long screwdriver or extension into the spark plug hole and turn the engine by hand with a socket on the crankshaft. When the screwdriver stops rising or falling you're at TDC. Don't turn the engine backwards if TDC is missed. Go around again.

Note: In our engines, cylinders one and four and two and three are at TDC at the same time, but you need to be sure the one you are testing is on the compression stroke; in other words... make sure all the valves are closed for the cylinder being tested.

2. Put the vehicle in gear and set the parking brake to help prevent the engine from turning when air is compressed into the cylinder. You can also use a wrench on the crank bolt, but be sure to orient it so that it won't loosen the bolt!

3. Select the correct adapter and screw the short air line into the spark plug hole (without the tester connected), and hand tighten it by turning the hose.

Note: Adding a bit of oil to the o-ring on the adapter will help it seal and keep it from wearing out as quickly.

4. With the regulator turned fully counter-clockwise, connect your compressed air to the tester's inlet. Turn the regulator knob clockwise until the percentage guage reads "0" or "Set", and then lock the regulator (usually by pushing in on the knob).

5. Connect the guage to the adapter line that's screwed into the cylinder, and record the leakage percentage for that cylinder from the second gauge of the tester.

6. Remove the oil dipstick, radiator cap, and oil filler cap and listen for escaping air.

7. Open the throttle body, pull the BOV line at the intake manifold, and listen for air leaking in the intake and exhaust.

8. Close everything back up, and repeat for the other cylinders.