1997 Honda Civic Cpe - Compression issues

I have a 1997 Civic, over 300k miles. The compression is 82, 110, 70, 62 on cylinders #1 to #4. The check engine light comes on ONLY IN NEUTRAL for cylinders 3,4. When the car is running on the highway, it’s still fine. Usually the idle is pretty rough, down to about 500 RPM and it drifts up to 600 RPM.

I know the compression is bad, but this car hangs on to life dearly. I bought it new actually. Has never overheated or run low on oil. I wonder where I could start looking? The PCV valve is old, and I would change it but it is hidden.

The PCV is not the problem. It’s worn out due to high miles.

Go back and run a wet compression test. This means a small squirt of oil into each cylinder before it is tested. If the numbers go up substantially this means a piston ring problem. Going up very little means valves in the cylinder head.

I think you are going to find that it’s nearly reached the end and it’s not running nearly as fine on the highway as you may think. There’s no way it can be running anywhere near its optimum. You have just become acclimated to the poor performance.


Have the valves been adjusted? I do them on my 1999 Civic every few years, when I change or clean and gap spark plugs.


Agree with @ok4450, the engine is this vintage Civic is solid but has it’s limits. Getting 300K miles out of any engine is fantastic . Sounds like you took care of it.

Get a can of Restore or your favorite miracle in a can (STP etc) from your local auto parts store and see if that helps any.

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Thanks everybody. In the next couple of days I will check the wet compression and valve clearance. I did adjust the valves a couple of years ago. I’m only a kind of “intermediate youtube” mechanic and they may have come loose on me.

There is a bit more to the story… actually my car would not run at all without Engine Restorer. I neglected to add it after one oil change after using it religiously for years. Soon the car was throwing codes, but it was cylinder 1. I read only 40 PSI. But with Restorer it doubled, literally. I was amazed.

But, I don’t think that is the issue now as I top off both oil and Restorer.

I’d be fascinated to know why the engine does not throw codes in Drive but does on Neutral. The RPM stays about the same, hovering from 650 to 700. It takes a couple of minutes for the check engine to come on.

Also I see some fluid dripping from the exhaust, possibly coolant or gas or both. I couldn’t figure out what it was.

Interestingly, the car seems to run OK (but like ok4450 says, maybe I’m used to it) after it’s nice and warmed up and has driven for a while. It is at it’s worst if I drive it for a while, let it sit for half hour, then start it up. It really struggles then, but after 5 minutes or so, is OK.

Thanks everybody. I should really take it to a mechanic, but they just tell me to get rid of it. Actually 4 years ago a mechanic told me to get rid of it. Maybe this is it finally… I feel like I can keep it going a year or so if I tweak it a bit.

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As long as it keeps running, you can live with the lack of power, and you don’t need to pass emissions inspection, keep driving it until you can’t. Save your money in the meantime for a newer vehicle.

At 23 years old and 300K miles, this car has served well.


If there is blue smoke coming out the exhaust pipe, register the Honda and keep it through November 3. At 23, it’s old enough to vote! After that, replace it with a newer car.


It is old enough to vote :slight_smile: …It’s actually got 333k and has gone ~50k since the first mechanic told me to get rid of it a few years ago… I don’t see blue smoke or an unusually large amount of ordinary smoke out of the exhaust. I see a small amount of moisture though dripping out but it wasn’t enough to determine exactly what it was. I might try one of the radiator additives for blown head gasket.

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That puzzles me too but I’m not a mechanic and I have no idea. The “fluid” is probably just water. It’s a normal byproduct of the catalytic converter and most cars drip a bit from the exhaust.

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I bet that liquid coming from the exhaust is water, which is a natural byproduct of combustion.

As for the head gasket additive… I’d be wary of putting that in my radiator/cooling system unless you know for sure there’s a problem. Sometimes those products can cause more problems than they solve.


If the body is still in decent condition, why not try a used engine from a junkyard? These cars are very common, and it should be possible to find one which was involved in a side or rear collision, which means it was running at the time of the accident, and unlikely to have suffered mechanical damage due to the accident. If you can DIY, or find someone willing to do the work for a reasonable price, it could be worth the cost.

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Thanks everybody

Well, the body is kind of worn, but not too bad. I hit a deer a few years ago.
I did look at the valve clearance, and it was pretty bad. So, I adjusted (I think) to very nearly the specs. I cleaned off the distributor cap, and also sprayed anti-gunk into the air intake. But, none of these things helped. I started the wet test, but I had some problems finding a decent hose to get down there with the oil. I only tested one cylinder which went up by 10. But, bad news for me! The car is now dying altogether in idle, so I am out of tricks. I’m going to try a mechanic. It seems like if the car still runs basically fine other than idling it can keep going a bit longer, right? Can compression be so bad that it’s impossible to idle, or can I tweak the idle up at the source? I haven’t tried that.

PS., I see a lot of warnings “don’t adjust the idle screw!” I have a suspicion now my problem is in the vacuum system which I am ignorant of.

In all honesty, I’m surprised the car even started with compression that bad. The 110 and 80ish is the only reason why.
When compression drops too low any engine won’t start. The one cylinder going up by 10 points to a valve problem but there are some variables here considering the mileage.
I think you are wasting your time fretting over a mechanic, idle screw, vacuum, or anything else.

A dealer I worked for sent a low miles (cold weather at the time) Ramcharger to the shop for a no-start condition. The Dodge smelled of Ether which the lot porter was very fond of using.
The Ether had washed the cylinder walls down to compression readings of 40 to 105 on all 8 cylinders. A healthy shot of oil into each cylinder and reinstalling the plugs had it starting right up. This would not apply in your case because the Dodge had a healthy engine in it and yours is just worn out.

Due to age and miles the car is not worth the expense of a new engine so as suggested it would be much easier and cheaper to go with a used one if you want to keep driving the car.

@ok4450 that sounds like a good suggestion, the used engine route. I have a feeling my cyclinder 2 is doing most of the work now, the one over 110.

That is not an idle screw, it is a throttle stop screw. Your vehicle has a two part TPS (throttle position switch). One part is a variable resistor that tells the computer the position of the gas pedal, the other is a double pole switch. One pole tells the computer that your foot is off the gas pedal (IPS, idle position switch), the other tells the computer when you are WOT (wide open throttle).

When the IPS makes, the computer takes over the idle speed via the air bypass valve in the throttle body. If the IPS is not working, the engine won’t idle properly.

If you are losing coolant, and only if you are losing coolant, using the Subaru Coolant Coolant conditioner will help. But if you are loosing compression due to a blown head gasket and you aren’t losing coolant, then nothing you put in your coolant will help. You might try retorquing your head bolts to around 60 ft lbs.

But truthfully, I think you need to rebuild the engine or consider another vehicle.

@keith Thanks, that is very interesting. It’s a common car to restore and I’ve always liked it so kind of leaning toward a project. Young guys like to mod this car with huge engines. Probably I will just try to restore it its more or less original state. I like it when you see older cars that still look the same.

If you’re thinking project car, find a couple of good Honda forums to lurk at for a while, then pick one (or two) to join. This will provide contacts with people who have gone before you and have a wealth of knowledge of what works, what doesn’t work and how to make it work. High boost turbo charging with nitros is popular for these engines.

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Thanks, that does sound like fun – a more powerful engine. One issue with me is that I have driven this car now for literally nearly half my life, so it’s hard to part with it. I’m just used to it. Prior to that I owned a lot of bad cars, started on a Pinto, a Ford later that had a knock, a fairly good Buick that knocked and pinged. Still, even the shape the Civic is in now it still drives better than that lot. The computer yesterday seemed to recover enough to keep the car from dying at idle (either that or my valve adjustment helped). ANyway it’s going in next week.

@jazzbox35. I understand your feeling. I kept the first new car I bought for 33 years. My son was almost 5 years old when I bought the car. I hadn’t had the car a month when my son was shaking a bottle of root beer that had a cork to keep the rest of the bottle from spilling. At any rate, the cork blew and root beer went everywhere. I made my son help clean up the car and I said, “You have to help take of this car. Someday, you will be taking girls on dates in this car”.
Eleven years later, when my son went on his first date, he reminded me of what I had told him years before and he said, “You weren’t just kidding back then were you, Dad”?