Good Idea Bad Idea? drive a civic with no compression on a cylinder

Nov 29, 2005 13 Replies

As mentioned in previous posts, my sister's 99 civic has a damaged valve on cylinder 3 due to a timing belt breaking. The car is running, albeit poorly due to no compression on cylinder 3. Once you rev it up, it sounds OK.



Would it be safe to drive the car across town to a different mechanic in this condition? What are the risks? Or should it be towed?



The drive would be in the city, 50 km/h or less, and revved as low as possible. Its about a 14km trip.



Please advise.



Thanks Terry in Winnipeg


and by risks, i mean could we do further damage to the cylinder/piston/valvetrain by driving with no compression and a damaged valve.

t

T L wrote:

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I'd remove the spark plug wire from the plug and put an old 'dummy' plug on the wire, with the metal part of the plug grounded, so it sparks normally. Otherwise, I doubt anything bad could happen. (the high tension needs to find it's way to ground or it will 'blaze a new trail" inside the cap, or igniter)

'Curly'

Curly, not sure what you mean. How could I ground the 'dummy' plug? (IE make it stay grounded while driving the car.)

Also, if the gas in the cylinder is not being burned off, wouldn't it cause the oil on the cylinder wall to be washed away, causing potential damage to the rings, and contamination of the engine oil? This is one of the big concerns I have.

'Curly Q. L>> and by risks, i mean could we do further damage to the

This brings me to what I would add - disconnect the injector. Injecting fuel into that cylinder will come to no good.

Mike

"Michael Pardee" wrote in news: snipped-for-privacy@sedona.net:

yes,the unburned fuel will throw off the O2 sensor,and the ECU will misadjust the other cylinders.

Better to just leave the spark plug the way it is,not provide a "dummy" plug.

Thanks for everyones input! I will unplug the injector and leave everything else as is. For a short trip, I doubt it will create any big problems.

t

Jim Yanik wrote:

I'm imagining the combustion chamber pooling up with unburned gas, or would it just shoot out the exhaust valves anyway?

Is it really worth it to try? What will you save? $50 or less?

I wouldn't do it.

G-Man

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The other guys are more correct . . Unplug the injector. No worries about any backfiring, but you might still generate a 'misfire' code, but so what? At least it can't backfire if there's no fuel/air mixture present.

I was referring to chassis ground, like any part that's steel. Doesn't matter anyway, but it's worth remembering. Honda spark has to go _somewhere_ or it will go to the wrong places.

'Curly'

14k's are no problem. it's just one or two valves a little open - nothing different to a burnt valve. and don't worry about driving normal speed - if anything it'll be better as you'll get less blowback if it's on the intake side.

With one of these,

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part number 2756 for HEIsystems.

Eric

"MAT" wrote in news: snipped-for-privacy@comcast.com:

Of course it would get pushed out the exhaust.The cylinder still remains an air pump.A little leakage around a bent valve is not going to stop that.

The injectors atomize the liquid,so it will be a burnable fuel-air mix,vapor,not a liquid.

"'Curly Q. Links'" wrote in news: snipped-for-privacy@interbaun.com:

Let it spark in the cylinder,it won't harm anything. No fuel-air mix to burn with an injector disabled,but that does not matter. Those engines(non-Honda) that share a coil between two cylinders do the same thing;allowing a spark in a cylinder with no fuel-air mix.

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