Rep Power: 0

02 civic 266K, rough idle been getting worse over time.

i have done a bunch to try and find the issue but im stumped, this is an LX so it does not have an EGR valve.

what i have done so far; took the throttle body off cleaned it throughly, did idle relearn, changed spark plugs, changed out coil packs, since i have been getting p0301 (cyl1 misfire) lastnight i took fuel injector 1 and swapped it to cyl #2, no difference.

i dont think the cat is clogged, wouldn't it smell like rotten eggs?

friday night ill be tearing out the intake manifold and see if the EGR ports are clogged. after that im stumped, any insight would be great

thanks

 
Rep Power: 0

one thing i forgot to add, when im highway driving there is little notice of a misfire and the CEL is not blinking.

once i get off the highway and stop at a stop light the idle is rough and the p0301 misfire occurs, i put the e brake on and rev the engine up to 2000 RPM and the misfire stops

 
Rep Power: 519

Do a real compression test before anything else.


The EGR passage misfire will not occur at idle so don't waste time tearing the manifold off yet.

 
Rep Power: 0

Ezone hit it with the compression test suggestion. Maybe you have sticking/burnt valve(s).
Try it before going further. It doesn't matter if you think the misfire goes away at higher RPM.

 
Rep Power: 0

When I sta rted troubleshooting I did s comp test on cyl 1 where the mis fires were coming from. I got 140 psi on that cylinder. I'll b doing another tonight after work and post back.

 
Rep Power: 519

You must test compression on all 4 cylinders.

 
Rep Power: 0

well ......looks like the civic is just about dead

compression test lastnight:
cyl1 - 0psi
cyl2 - 80psi
cyl3 - 84psi
cyl4 - 100psi

i dont feel like tearing off the top end and re doing it, i dont know. its going to need another clutch soon, timing belt, rings, valve job, valve seals, head gasket, water pump, tensioner. probibly crank seals too

 
Rep Power: 519

Why is this test result so vastly different from the previous?


If I were to keep it, I'd group this into 2 separate jobs (If the engine is not pulled out of the car for the repairs). Everything engine related as one job EXCEPT the rear main crank seal, which would become part of the clutch job when the trans is pulled off.

 
Rep Power: 0

not sure how/why we got 140 on the first test , but dad and i did this one 3 times last night cus i couldn't believe my civic is almost dead.

i even put my hand over cyl1 and didnt feel a puff as i was out of 2-3-4.

unfortunately i have to drive the car to work and to clients, just praying i dont throw a rod till i find something else.

 
Rep Power: 519

Since Hondas tend to tighten up the valves--- see if the valves are tight on #1. Check all of them.

MAYBE, just maybe, it hasn't burned a valve yet..... but don't hold your breath.

 
Rep Power: 0

Odd how, if the valves are indeed tight... that the tightness is progressively better away from #1.

If anything, the exhaust valves with be the ones that are tight... and those are certainly valves you do not want hovering free over the valve seat (valves stay cool by transferring their heat to the head through contact with the seat).

Rocker arm valvetrains however, tend to get looser as they approach op temp -- so there is the slight chance (very slight) that your valves just need adjusting, as the D17 rockers are much, much larger than the B- or K-series rockers (which are more followers than conventional rockers). Good luck!

 
Rep Power: 0

thanks guys, ill try a valve adjustment this weekend.

if i do have to do a rehaul can i leave the block in the car and just pull the top out? or is it easier to pull the full motor

thanks

 
Rep Power: 519

I sure don't pull the engine if I don't need to. I have no problem removing the head from that Civic with the engine in the car.



Don't look in my bay right now though. I have an entire Odyssey drivetrain on the ground because I thought it would be faster to get the heads off of it this way.