I just did a compression test on my 2000 civic si w/b16a2. the readings are cyl4: 180psi, cyl3: 175psi, cyl2: 170psi, cyl1: 160psi. I was just wondering it they are good. My autoshop teacher says it is but i remember other threads w/ ppl having compression test #'s up in the 500's-400's-mayb a different measurement??

 

The one readings are not that great considering A. your best cylinder is about 20 PSI short and B. If you have a 10% difference between the four than your usually good.

a used motor with 8.5:1 compression will make 150 PSI . I would say you are into a rebuild maybe.

Excel

 

when i was doing the test, i forgot to take out the ecu fuse so no fuel would be injected, but i guess the fuel was injected so mayb it cause the nubers to go down in the cylinder order?. I tested from cyl4 to cyl1. I also forgot to put the car at wide open throttle. i think i should do a redo but would those factors cause the difference???

 

Do the test over your allowed 5 cranks. Do it with open throttle. The fuel inside would have little to do with the test. But you might as well take the fuse out so you dont get fuel in your test guage.

Excel

 

the engine also has to be up to operating temp for those numbers to be accurate

 

Should be about 200. Try it with the engine at operating temp and an open throttle.

 

my engine temp was at operating temp but would wide open throttle cause the difference? i did the test at school so i won't be able to retest until 2 marrow.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMaLLDAy050 &raquo;</TD></TR><TR><TD CLASS="quote">my engine temp was at operating temp but would wide open throttle cause the difference? i did the test at school so i won't be able to retest until 2 marrow.</TD></TR></TABLE>

Yes you need air to get to the cylinders to get good compression!

 

I found no difference between WOT and closed throttle in my test. Disconnect the dizzy too and remove the fuse for the main fuel relay and you're good to go.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dpkelly &raquo;</TD></TR><TR><TD CLASS="quote">I found no difference between WOT and closed throttle in my test. Disconnect the dizzy too and remove the fuse for the main fuel relay and you're good to go.</TD></TR></TABLE>

Well the helms guide says to do it, and i HAVE notice a difference with WOT vs closed throttle, up to about 10-15 psi. just for reference JDMaLLDAy050 my b16 gets about 205-210 on all cylinders with the test done correctly by the helms manual. And definitly disconnect your dizzy if you haven't, it won't change the number obiviously but you can fry your dizzy and that can be costly.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dpkelly &raquo;</TD></TR><TR><TD CLASS="quote">I found no difference between WOT and closed throttle in my test. Disconnect the dizzy too and remove the fuse for the main fuel relay and you're good to go.</TD></TR></TABLE>

no need to touch the dizzy, i just pull the spark plugs and unplug the injectors.

 

Mine has 235-237psi across the board, H22A though
How many miles do you have?
My car before(prelude) had about the same as yours, 165-180psi.....but it still ran well.

 

also if you have aftermarket cams your readings will be slightly lower...your valve adjustments also have allot to do with compression....I also never noticed a difference betweent WOT and Closed...IF you think something is wrong with your cylinders pour a capful of oil(Oil cap) into each cylinder and recheck if the numbers go up considerably...(40 and up??) then your rings are bad....other than that you'd need a leak down tester to figure out if you have bent valves or something like that...but yeah readjust your valves and check them again.

 

i do have aftermarket cams but they are set a zero. im not sure if my timing is right but my car runs pretty steady but does not pull as hard as it should. I only have trouble running cuz of richness which i am trying to figure out why. everything else is fine, no burning oil cuz my oil level has been the same and hasn't droped, my fuel consumption is bad tho, it wastes alot. car has 69k. I think im going to do a retest 2 marrow again. so this time ill make sure to go wide open throttle, pull my injector plugs, and disconnect dizzy. i hope there is nothing that serious with my car! o yea, when my car was crankning, my auto teacher says it's suppose to crank fast but it went pretty slow. any idea?

 

depending on the stage of your camshafts...it maybe because the cams you are using are really wild causing a loss of vacuum in the intake manifold...which then tricks the map sensor into thinking it should drop more fuel...i had the same problem with my skunk2 stg 2 camshafts. You will need something such as a VAFC or a hondata to tune this out....a FPR may help but not much....and you may end up running lean in the high end..not sure


also when you do a compression test there should be a slight pause after the gauge moves up...if the motor spins really fast like there is no resistance in the motor that is not good.

 

i know i said cams but i meant to say cam gears. im not sure which ur refering to but yea, i have cams gears set at zero. but the thing is, im only running rich in cyl 4.