compression question

[93 gsx skidz]

I did a compression test and when I loosened 3 of the four spark plugs I got 145 and when I stopped cranking it drops down to 120 in all four cylinders with no difference then when I do it with the spark plugs tight I get 150 and when I stop cranking it still drops down to 120. Do I have a problem

 

[Calan]

You need to remove all the spark plugs when doing a compression test.

http://www.dsmtuners.com/forums/articles-engine-fuel/338152-compression-leak-down-testing.html

 

[BogusSVO]

Yes, your compression gauge is leaking.

There should be a manual release botton on the comp gauge. to set it to zero.

A shraider (tire) valve in the gauge thay may have worked loose.

A proper comp test is done with the engine warm, all spark plugs out (disable fuel and spark) and the TB at WOT

 

[93 gsx skidz]

OK thank you and how do u put a 4g

63 in time ### my marks aren't lined up

 

[bryanwheat]

OK thank you and how do u put a 4g

63 in time ### my marks aren't lined up

First off, STOP cranking it over with the engine out of time. You can bend the valves if it is out of time enough. Second this has been covered many many times on this site.