Hi all,
We have a 1991 manual Honda Civic DX hatchback (base model, no power steering, no A/C) that has been in the family for many years, its now done 320,000 miles, been stolen 3 times and recovered. It recently passed from my daughter to my son, he loves it because its economical and he can fit a double bass in it. It still runs as sweet as ever no smoke and idle seems good.
Sadly it just failed its California smog test, reputedly on high HC emissions at idle. My son has fitted new air cleaner, overhauled the ignition system (distributer cap and rotor were in poor shape - replaced) checked spark plug gaps etc. The spark plugs look fine all about the same color (approved brown, just like the pics).
My immediate reaction was EGR valve but we don't think it has one (only on automatics in California apparently), we are wondering where to look next, I have a compression tester on order and will be looking at that next week.
Assuming the compression test is OK where would be a good place to start? IACV valve? PCV valve? Catalytic converter? (its Pre-OBD2)

Any suggestions are most welcome,
Geoff

hefy_jefy is online now Report Post

 

Check the mechanical and ignition timing to start - bad timing could have an effect on emissions. Clean the crankcase baffle and PCV valve.

Compression test would be good, but if you aren't smoking it is probably OK.

If the idle is good the IACV is probably OK, if you unplug it idle should dip to around 600 RPM or so.

 

OK - Many thanks! we will take a look - I have a timing light somewhere in my garage...
Geoff

 

retard the timing may help you pass.

 

Thanks yes, I was reading about retarding the ignition a tad, it was very slightly advanced when we checked it also the PCV valve was choked with carbon and the spring was broken. Compression is good, right around 150 - 160 which for an engine that's done 320,000 mile is amazing.

 

what numbers are you seeing? Does it still have the oem original cat?

 

Your injectors are leaking fuel. Replace them