2000 honda civic cylinder #3 misfire stumped

[kmjturner]

For the past 4 years this car has been plagued with a misfire in the #3 cylinder only! I have replaced the engine, replaced the cylinder head, rebuilt the cylinder head, and replaced exhaust valves with no success. The issue constantly comes back within 6 - 8 months after repair. I have done all the repairs myself and I am confident that I did it correctly. I was thinking that maybe the distributor or ECM could cause this since the problem still persists after engine and head replacement. Has anyone come accross a problem like this?

Mark

 

[AlaskaB16]

Dizzy, plug wires, plugs, and I do believe the ECU (i'd have to double check that) can all cause a misfire. I had this problem in an Acura CL though the problem was oil getting into the cylinder and following out the plug.

 

[kmjturner]

Yes over the past 4 years I have replaced plugs, wires, coil, rotor, cap, injectors etc. with no success. the problem has to be related to the dizzy, ECU or maybe wire harness. I am going to tear down the engine again this weekend and lap the valves, most likley the 2 exhaust valves. Problem is no other cylinder is affected and this is a different engine and cylinder head, no matter what I do it is always that cylinder.

 

[AlaskaB16]

Does the car run poorly or smoke? I assume you're reading a code that is telling you #3 misfire? I know i've misread codes before in the past when trying to count the CEL light codes. Is your car modified at all?

 

[TigBitties]

im confused as to why you jumped right to the engine, most misfires are not an engine issue but rather a timing/fuel/ignition issue. have you tested the coil and ICM?

 

[mymmeryloss]

 

[kmjturner]

Compression in #3 cylinder only has 70 PSI and the rest are around 150-160. Over the past 4 years this is what plagues this car, I repair & replace parts (heads, engine, coil, wires, cat, injectors, valves etc.) then around 4 - 8 months later my idle craps out and it starts to stutter and misfire. The only parts left to replace is the dizzy, ECU or wire harness for the injectors. This has me stumped because no matter what I fix or replace the same identical problem persists, #3 cylinder low compression every 6 months or so. Any help is very much appreciated.

Mark

 

[THEDARKONE]

your compression rings are shot simple enof if you do a leakdown test you will probaly see that you are getting blowby since everything else is good the only place for the air to escape is the oil pan time to get new rings or rebuild...

 

[JeffBel]

How the fuuu? Who's rebuilding this engine? One set of rings going bad in 6 months is unheard of.

 

[kmjturner]

its not the rings, it is always the exhaust valves and always #3 cylinder. I have tried to move things around to see if the problem would transfer to a different cylinder but with no success. different head and different engine, same result.

 

[TigBitties]

is cylinder three injector pulsing?

 

[JeffBel]

Or maybe the ecu has a bad tune and misfires the hell out of cyl 3 until the valves bend?

 

[TigBitties]

Or maybe the ecu has a bad tune and misfires the hell out of cyl 3 until the valves bend?

its common for low side drivers to go bad, which could be causing this misfire in one specific cylinder. i had an issue with my #1 cylinder

 

[kmjturner]

Tore engine down last weekend and all 8 exhaust valves were leaking including 2 intake valves in #3 cylinder. Back together running fine adjusted intake valves .008 and exhaust .010. (compression across all cylinders 150-160), is there anything I may be missing since this is a constant problem? any help will be appreciated.

 

[00siboy]

You still haven't answered anyone's questions about mods/ecu. It would help to eliminate some things.

Burnt valves come from too hot of combustion chamber temps, which can be caused by valves not seating, lean condition, bad EGR flow, overly retarded timing, pre-ignition, or wrong mechanical timing. Did you replace the valves when all the engine work was done, or simply just lash them?

 

[TigBitties]

something feels missing here. rebuilding will not fix the issue. are you running the right plugs? is it rich? carbon build up? timing set? somethings not right

 

[kmjturner]

Sorry about that, No mods all stock. I just lapped all leaking valves and current compression is 150-160 across all cylinders. I am going to change the plug wires, plugs, cap & rotor just incase to avoid this issue in the near future.