Hey guys, Im going to do a compression test on my 93 gsr 1.7 for the first time since ive owned it. Anyone happen to know what are the “normal operating numbers” for a B17 engine? Also this will be the first time i ever do a compression test, any advise? I know i have to disable the fuel injection system by pulling the fuse out (on 3rd gen integras its fuse #15 under the hood is it the same for 2nd gen Integras?) also foot placed on the gas pedal at WOT, and disconnecting the distributor. Anything else i should do???
Sounds like you have a good procedure narrowed down… I don’t know the numbers honestly, but more importantly the best thing is to make sure all the results are within 10% of eachother.
This tells you that they are all wearing the same.
no need to disable the fuel system. WOT initiates fuel cut. remove all spark plugs when performing the test to give a more accurate reading. disconnect the distributor as well so you don’t fry the coil
According to the Factory Manual the Minimum is 135 psi with Nominal being 185 psi
ok cool, ill def post up the numbers that i get in the next couple of days to see what they are. My DB2 has 193,xxx miles bone stock and its running pretty good with no issues at all.
This is the service manual right??? i think i do have this one laying around somewhere
Yeah this is from the service manual
Ok so here are the results of the compression test: Note, this was a dry test only.
Cylinder 1: 180psi
Cylinder 2: 165psi*
Cylinder 3: 150psi*
Cylinder 4: 180psi
Should i be worrying about cylinders # 2 and 3???
I would preform a wet test as well. 2&3 seem a little low
yea im probably going to do that tomorrow. What if the numbers drop or rise on cylinders 2 and 3??
The numbers should rise, which would indicate leaky piston rings.
Wait… so in other words i may have a leaky piston ring???
The two cylinders are low because air is escaping the cylinder during the compression stroke…
The air can only escape a few places… Piston rings, or valves (or head gasket, in extreme cases).
If you add oil to the cylinders and do a wet test. The numbers should increase, indicating that your air is escaping from the cylinder rings. The oil creates a seal in the worn piston rings, and increases compression.
The sure-fire way to find out where its leaking is by doing a breakdown test.
usually you don’t wanna see anymore than a 10% variation between cylinders. i’d run the dry test again. just to make sure.
considering the 2 cylinders are adjacent though, i’d have to guess headgasket. usually the head will bow closer to the center (cyl 2,3)
Valid point sir.