01 civic si no compression cyl 3
 

Hey folks, hoping for a miracle here. 01 civic si v tec with 307,000km. Left work the other day cold motor and accelerated through the gears. from third to fourth my engine light started flashing and performance dropped. limped car the 35km drive home and scanned. P0303 code. Changed plugs swapped coils still no difference. Did compression test and #3 had nothing. Okay head gasket I thought. Put new oem gasket on yesterday , got it all back together and still no compression. Piston is not destroyed and valves appear to operating as they should. We manually turned cam while we had the head off to see and all looked good. I could not see any signs of failure on the old head gasket either. We did NOT remove the intake while doing this job so I have no idea what the gasket looked like. Im really at a loss . Is there something Im missing here ? Something to do with the V-tec side if things or bad intake ? It fires up but it is trying to learn idle so it revs up and down. there is no mechanical knocking or grinding sounds so im certain things are good there. Timing belt is not due for another 50k so we tied up gear and belt while removing head.

Re: 01 civic si no compression cyl 3
 

absolutely zero compression would be a very major leak,

assuming you did the head gasket job correctly there are really only two other possibilities, damaged valves or timing incorrect, or a combination of both

Re: 01 civic si no compression cyl 3
 

I'm confident gasket was done correctly. I'm not sure how timing would have changed . It ran great before the problem started. As I said , we didn't pull valves out but definitely checked to see that they were operational by rotating the cam while the head was off. It's frustrating as hell.

Re: 01 civic si no compression cyl 3
 

Yes. See why there is no compression in only one cylinder before you remove the head, so you know where to be looking if/when it does come off.

Cylinder leakage test should have been done immediately after finding low compression.

Valve adjustment? Tight valves can cause low compression.

Re: 01 civic si no compression cyl 3
 

Agreed, a leak down test should've been performed. Is it possible for a vtec actuator pin (not sure on exact name) to be stuck causing intake valve to hang ? Let's remember that this happened when I stood into the throttle.

Re: 01 civic si no compression cyl 3
 

IDK for sure....but I doubt it....(I assume you did not pull rocker arms off or apart while the head was off).

You said watched the valves open and close while the head was off, yes?


While the head was off, did you liquid check the valves to see that they actually seal?

Re: 01 civic si no compression cyl 3
 

no I did not

Re: 01 civic si no compression cyl 3
 

you can bench test valves, or cylinder leakeage test on car before you take it off..

i do first test on the car.... make sure your cam bolt didnt come loose.. thats what happen on mine.. bent 12 valves... what was the bad compression number?

Re: 01 civic si no compression cyl 3
 

We checked the valves when it was off and all appeared to be fine. Not to say that we missed something there. Once back together again we fired it up and still no better. Pulled #3 plug and did comp test. Gauge barely registered. Basically zero. I'm missing something in that head. Can't be anything else.

Re: 01 civic si no compression cyl 3
 

Well, you've got it back together and you found low compression. Now would be a great time to do this:

Re: 01 civic si no compression cyl 3
 

zero compression to me would indicate a valve MUST be stuck open,

i had a motorcycle with low compression in one cylinder, i pulled the head and found a valve was cracked with a small hole in it about the size of a pencil or a bit smaller,

this cylinder was still registering a small amount of compression,maybe 30 pounds or so, so for you to have zero compression must mean a god dang pretty big leak

Re: 01 civic si no compression cyl 3
 

Couldn't agree more with you. I'll be honest , I've never done that before. Any advise or links ?

Re: 01 civic si no compression cyl 3
 

See if google is turned on in your area? (yeah I'm a smartazz)

http://www.hotrod.com/how-to/engine/...akdown-tester/

https://mobiloil.com/en/article/car-...-leakdown-test

You don't really even need a real gauge set to quantify some amount and assign a number to it,,,,, all you really need right now is to apply air pressure into the bad cylinder (correctly) to figure out where the air pressure is escaping to (leakage).

Re: 01 civic si no compression cyl 3
 

[QUOTE=ezone;4705802]See if google is turned on in your area? (yeah I'm a smartazz)

LOL, we'll deserved. I realized after I posted how stupid that sounded.

Been looking and I have several local places selling complete motors for $500 (Canadian) claiming to be imported from Japan with low low km (sure they do). Makes we wonder why the hell Im messing with my 300,000 km engine.

Re: 01 civic si no compression cyl 3
 

[QUOTE=jaylo600;4705823] New-to-you doesn't necessarily mean it will be great.
Most of the 1.7 engines need a head gasket job sooner or later, so be forewarned.