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Discussion Starter #1
I have low compression in one of my cylinders. I'm also noticing exhaust in the cab when I'm idling with the heat on.

Could an exhaust leak in the right place cause low cylinder compression?
 

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Compression is a measurement taken with both valves closed.
If you are hearing a blow by, it's coming most likely from a failed gasket in the exhaust system or hole in the system. Both are pretty rare these days.
 

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Discussion Starter #3
I say I have low compression because I have a misfire on all cylinders. Took it in to the shop and they say cylinder 2 has low compression. He said it was most likely a burned valve, but there's no tick.

I forgot to ask if my exhaust leak could be causing it. What you're saying sounds like it's not, but I want to make sure before I make the call that the car isn't worth repairing.
 

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It is most likely a leak in your exhaust system, probably near the cat converter.
Could be anywhere in the exhaust system, but NOT from a valve.
Make sure the Outside Air is selected while using the heater as that will put a little positive pressure inside your CRV and should help keep out your own vehicle's exhaust gases. Using Recirculating will not do that and is dangerous if you actually smell your exhaust gases.
What yr is your CRV and what is the mileage and was the valve lash every adjusted?
How many miles since you got those codes?
Buffalo4
 

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All multi-cylinder engines will have a highest compression cylinder and a lowest compression cylinder.........even if it's a new engine. Did the shop tell you numbers? High to low should vary 15% max. Did the shop do a cylinder leak down test to determine which valve(s)?
 

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I forgot to ask if my exhaust leak could be causing it. What you're saying sounds like it's not, but I want to make sure before I make the call that the car isn't worth repairing.
You have two different issues going on. An exhaust leak and possibly a burned valve, but they are not related (one does not cause the other).

Our Civic burned a valve after a Bosch spark plug shattered in the #2 cylinder--it at first lost some of the compression but, after a while, finally lost just about all of it. It was easier for me to buy a rebuilt cylinder head and replace it, as they are cheap and plentiful. But I can do the work myself, vs. paying a shop to do it.

Coincidentally, we also had an exhaust leak in it. Our generation of Civic has a known problem where the exhaust manifold develops a crack; it's not a cheap repair since the exhaust manifold and catalytic converter are all one piece. The evidence there was a ticking sound until the engine warmed up; after I replaced the cylinder head, it ticked all the time and of course smelled bad, so I replaced it.

For your exhaust leak, it could be anywhere. If it smells like "raw" exhaust, it could be anywhere from the exhaust manifold to the inlet of the catalytic converter. It's probably not very expensive to fix, unless your CR-V is as bad as my '97 is, to where it's too rusted to work on anymore.
 

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Discussion Starter #7
Thanks for the info everyone.

It's a 2004 with about 206k miles at the moment. It first started flashing nearly two months ago now, I don't know, maybe something like 5k miles. No idea if the valve lash was ever adjusted, I got it about 2 years ago with about 170k miles.

Sounds like what I figured: burned valve, which will eventually get bad enough to kill the car, and would be more money than the car is worth at this point.
 
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