Rep Power: 0

Hey there All,

I have an 01 Civic sedan LX and had a recent loss in power (significant loss)
I checked compression in all for cyl. 1-3 have round 150 PSI cyl 4 does not even register. So I pulled the valve cover off hoping that I might find a sticky in take or exhaust valve on that cyl. No such luck every thing seems dandy under the cover. So I was wondering from all you resident experts what my next step would be.

Other symptoms: Idles a little rough, burns a good amount of oil round a quart ever 800 mi or so which was even prior to the power loss but I believe is in conjunction with my current dilemma. Any feed back would be great

Thanks
Saspi

 
Rep Power: 0

Sounds like an issue D17s have a lot -- tight valves. So you've put #4 cylinder into TDC compression, and felt for freeplay on all 4 valves? D17 valves from what I've been told here tend to get tight rather than loose over time, holding a valve open and preventing compression.

That's one of the nice things about having rockers on your DD -- only tools to remove the valve cover, then a wrench to spin your PS pump pulley center nut with spark plugs out... and you can rotate any cyl to TDC-C, and see if any don't have freeplay -- on a shim-over-bucket setup, there's no way to do it without a feeler gauge... plus with rockers, no shims needed to set clearance.

 
Rep Power: 518

Do a leak down test, if possible. That's how I figure out where the loss of compression is going.

If that's not available, then do a Valve clearance check and adjust first.
Hopefully they are just tight on #4 and didn't burn yet. (Check and adjust all of them anyway.)


What's the mileage?

 
Rep Power: 0

LD test is best in a shop environment, and it will immediately tell you which part is leaking (airbox/PCV=rings; intake/exhaust=valves).

For the home wrench, though... since valves are much easier to confirm with the cover off vs. listening through the intake or exhaust on a car (unless you have a probe stethoscope)... checking them with freeplay is easier, not to mention being able to correct valves that are *about* to go tight while you're in there.

The LD test would only be confirming ring leakage, and is easy enough to do if necessary, with the cover off. If ring leakage is found in #4... it's really not a job for a basic home wrench anyway, as head and big-end caps must come off to liberate the rings from its ring land & carbon prison.