Hey guys its my first post.

I just bought a 93 civic dx coupe, auto trans, 105k miles. It didn't crank or turnover when i bought it. Now i've got it running, but it idles like crap, timing sounds off.

It has a d15b7 bottom and a pm9-3 head, the previous owner said they put the head on, new distributor/wires/fuel filter

My diagnosis thus far:
Compression in the other 3 cylinders range from 155-175
#3 cylinder has no (0) compression
#3 spark plug has oil all over the electrode
it doesn't smoke that much from exhaust

I did try the old trick of paper on the tailpipe to check for maybe burnt exhaust valve, but it did not suck in only pushing air out along with some soot.

Any ideas or suggestions??
Thanks,
K

 

There's No compression in the #3 cylinder and you're looking for some kind of trick to fix it? Leakdown test then most like a teardown.

 

the rings on that cylinder are fried. did you attempt a wet compression test as well?

 

This is where I see this headed. Think about it, 0 compression. There's only really 2-3 different things that would cause this.

1. Burnt/cracked/chipped/bent valve
2. Mating surface warped/chipped/cracked or head gasket failure
3. Rings/cylinders way out of round/piston broke/etc

Basically either a valve, a piston assembly, or the head gasket is failing to seal. All of them require at the very least a partial to moderate teardown.

 

Pull the valve cover and look at the rocker arms - are they loose - narrows it down to a bent valve. Wet (oil) wide open throttle cylinder pressure test - if pressure comes back up crappy rings. Personally, even with broke rings, I have seen some pressure generate on engines, unless of course the piston is flopping around in the bore like a tick tac in a whales mouth... Sounds like a bent valve.

 

^^ You bring up a good point. Possible overtightened valve adjustment keeping a valve from fulling seating. Never know since you stated the previous owner replaced the head and it's worth a look anyway (and that would probably be a best case scenario).

 

Could be that too...

OP, what are the specs on the valves/rocker arm assembly for exhaust and intake? Do the valves need adjusting?

 

From the web about wet fouling:

"A spark plug shorted by excessive oil entering the combustion chamber is shown below. This is often caused by piston rings or cylinder walls that are badly worn. Oil may also be pulled into the chamber because of excessive clearance in the valve stem guides, or badly worn valve stem seals. If the PCV valve is plugged or inoperative, it can cause a buildup of crankcase pressure. This condition can force oil and oil vapors past the rings and valve guides into the combustion chamber."

 

I have not taken the valve cover off yet. That was going to be my next plan of attack, then maybe do a valve lash, but I did do the old burnt valve check with the exhaust tip, so I didn't think much into that being the cause. Also, I did not to a wet pressure test cuz it had 0 compression reading and figured it wouldn't make a difference.
Can you do a leak down test on a cylinder with no compression? It doesn't make much sense, but I've never done it so.....Also, do you do a leak down test on the cylinder in question with that cylinder at TDC?

 

For you to have 0 compression you need to have either a broken/stuck open valve. Or a 100% blown head gasket. Can you see inside of the cylinder? Is there a puddle of Oil in there?

 

Yes, cylinder being tested needs to be at TDC. Try shining a flashlight down spark plug hole. See for any visible damage

 

Any smoke out of the exhaust? 0 compression I am thinking prob bad ring, if so it is a swap or teardown, bottom end is involved now.

 

I tried putting my compression hose in the cylinder and then connecting my compressor to it, it seemed like it was holding air when the cylinder was TDC. Bizarre???? Im going to look for a leak down tester today.

I also did look down into the cylinder with a flash light. The top of the piston looked like it had a rough surface. The tops of the other pistons looked fine in comparison.

 

Yes there is some smoke,but I've had a blown head gasket on my old M3 and it's not really that smoky. More of a soot that's coming out.

 

Not looking for a trick to fix, trying to avoid a tear down. Trying to avoid taking off the head. If it gets to that point...thinking its time to look for a used engine.

 

Have you pulled the valve cover to look at the valve train?

 

Doing this tonight, anything in particular i should be looking for???

 

the valve mechanisms. The rocker arms, etc. See if anything is obviously broken, and check to see if all the valves are in their sockets and none are dropped.

 

Wow!! So i bought a stethescope and made a leak down tester since napa and oreilly's didn't carry one in my area (anchorage, alaska). I began by setting the #3 cylinder to top dead center, guess what, the piston did not move at all when I turned the crank by hand.

%$&@ mother. So looks like a broken piston and/or rod....

I think its swap time.

 

You have my luck with cars. It's never the less expensive thing that goes wrong.

 

ouch

 

The bright side is I knew it was going to need work, thats why I only paid $380 for the car. Ha
Tomorrow there's an auction with a 95 dx sedan, so hopefully I can get that cheap and do a D15b7 to D15b7 swap.