Okay... i've done the search but none of the stories are just like mine... So i've had my 1993 USDM H22A1 motor in my civic for about 2 years now and ever since the first start up back in feb of 02 the idle has always been a little rough and choppy. It's steady and doesn't stall out or anything but it's just a little choppy. not SMOOOOOTH like a normal h22. motor's completely stock with the typical tune up every so often.

Well i'm running on Hondata now and tuned making 180.1whp and people always tell me to get that idle fixed cuz it just sounds a little rough. So i do a compression check with a warm engine, about 96k miles on the motor and 6k miles on the spark plugs with numbers:

#1: 080; spark plug was BLACK AS HELL
#2: 220; spark plug looks fine
#3: 090; spark plug is in between #1 and #2
#4: 190; plug looks okay.

yeah... terrible numbers i know but the car still runs just as great as it did before and always has before i knew what the compression results were. I'm thinking it's either the valves or the rings. Will do a leakdown soon. I just needed some input. Let me know if there's anything else you guys need to know to help me out. Thanks.

 

you can try a wet compression test to tell if its the rings.


With numbers that low i would definetly get a leakdown test to see where you are losing compression. a stock usdm h22a1 shoudl be about 210 psi with no more then 20 psi variance between the 4 cyl's.

 

wow, that's increadible beacuse then my #2 and #4 cylinders are perfect... so what's wrong with #1 and #3? is it a coincidence that it's the odd # cylinders or is there some sort of reasoning to it? thanks.

 

I think that maybe your compression test method is at fault. I would suspect that such low compression on those two cylinders would cause more than just a rough idle.

Explain what the comp guage was doing when you measured 1 and 3... DId it shoot right up to 150 or so, or climbed really slowly?

Can you hear air excaping????

fs

 

Yeah, that's what we thought at first too so we did a check on a stock 98ish lude that was sitting around and his read 160ish across the boards. kinda low, i know. So i didn't think the instruments or method was at fault cuz we did it multiple times. Yeah, i figured such low compression would cause more problems but my car runs fine. It's never even been a problem. Apparently, i make 180.1whp with this compression . I'm also going turbo... so should i fix the problem first or go ahead and boost? 4psi on CT26 and stock injectors on hondataboost

 

how many times did you crank it over? i say keep cranking until the number stops. it can be that low and be running rite. double check the compression and see if the numbers are still low

 

If compression is that low, you should, in theory of course, have some oil on the plugs because it is passing through the rings or valves.

Now if the 2 'faulty' cylinders were next to each other, then that would be another story, but in your case, they are seperated by a good cylinder.

I suspect again that you should redo the test making sure that you reset every piston at TDC prior to installing the guage. This should give you 1 crank revolution.

fs

 

redo the test.

have the car at operating temp.
remove spark plugs
kill fuel supply ( pull the fuse)
Turn the engine over with the throttle wide open, until the numbers stop rising. i ususally do it for 6 revolutions.
move on to the next cyl.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zad5 &raquo;</TD></TR><TR><TD CLASS="quote">how many times did you crank it over? i say keep cranking until the number stops. it can be that low and be running rite. double check the compression and see if the numbers are still low</TD></TR></TABLE>
yeah, in regards to the number of times it was cranked, we did it for a whole 3-4 turns after the needle stopped. The numbers were so low that we took out the tester and put it back in.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by filthy_shovel &raquo;</TD></TR><TR><TD CLASS="quote">If compression is that low, you should, in theory of course, have some oil on the plugs because it is passing through the rings or valves.

Now if the 2 'faulty' cylinders were next to each other, then that would be another story, but in your case, they are seperated by a good cylinder.

I suspect again that you should redo the test making sure that you reset every piston at TDC prior to installing the guage. This should give you 1 crank revolution.

fs</TD></TR></TABLE>
yeah, so obviously it's the rings or valves. and there is some sort of reasoning that it's the odd cylinders? how do i know if the piston is at TDC or not? does it make a difference if it is or not because i've never done it that way... oh and i wasn't heraing for escaping air. maybe it wasn't screwed it tight enough? but we did it more than once. "Fool me once, shame on you. Fool me twice, shame on me."

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Behan &raquo;</TD></TR><TR><TD CLASS="quote"> redo the test.

have the car at operating temp.
remove spark plugs
kill fuel supply ( pull the fuse)
Turn the engine over with the throttle wide open, until the numbers stop rising. i ususally do it for 6 revolutions.
move on to the next cyl.

</TD></TR></TABLE>

hmm... never thought about cutting off the fuel or with the throttle open. what should the #s be with the throttle open? and yeah... i just turn the motor over until the needle stops moving after likek 3-4 revolutions.
-thanks guys.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DXR &raquo;</TD></TR><TR><TD CLASS="quote">

hmm... never thought about cutting off the fuel or with the throttle open. what should the #s be with the throttle open? and yeah... i just turn the motor over until the needle stops moving after likek 3-4 revolutions.
-thanks guys.</TD></TR></TABLE>

it should be about 210 psi with the throttle wide open.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DXR &raquo;</TD></TR><TR><TD CLASS="quote">

yeah, so obviously it's the rings or valves. and there is some sort of reasoning that it's the odd cylinders? how do i know if the piston is at TDC or not? does it make a difference if it is or not because i've never done it that way.

</TD></TR></TABLE>

I'm not sure what filthey shovel is talking about? Maybe he can elaborate....

Although he may be thinking of a leakdown test which is performed with the piston at TDC.

 

how much is the compression supppsoed to jump up when doing a wet comp test if the rings are bad? like 30-40? or 5-10?

 

whoa.... i wonder how your car would do with normal compression

you make me wanna check my compression now.....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DXR &raquo;</TD></TR><TR><TD CLASS="quote">how much is the compression supppsoed to jump up when doing a wet comp test if the rings are bad? like 30-40? or 5-10? </TD></TR></TABLE>

Normally, when you do a comp test, the needle on your guage should jump to about 2/3 on the first compression stroke, then go up the remaining 1/3 in about 2 additional strokes.

Now, if the rings are worn, you will see your needle jump in real small increments (20, 30, 40) psi. THis is because, as the piston compresses air, air is escaping through the rings.

One thing you may want to try is to blow compressed air in the 'bad' cylinders and listening for air escaping. Make sure your intake and exhaust valves are closed when you do this (so on the compression stroke or TDC). If you have problems finding this, take out the spark plug, put your thumb on the spark plug hole and crank slowly until you can't maintain you thumb on there.

A leak down test will help identify bad rings and such...

It is possible that you have bad cam lobes that are not raising the valves enough.

fs