Emission Failed w CO high at 1500

time260 · 03-29-2007, 05:56 AM

Please Review table ...

California Emission FAILED at 1500 RPM, 2500 Passed, CO2 @ 12.6 steady

Date CO% (max 1.36) Adjusted before next reading
13Mar 3.23 Idle & timing
14Mar 2.64 1 full turn CCW (lean)
15Mar 2.96 3 turns CW (rich)
20Mar 1.82 7 turns CW
27Mar No print
28Mar 1.62 45 turns CW
28Mar 2.11 ????????

79 SC, CIS 3.0, everything else is normal until my last adjustment. Is 45 turns normal, or do I have a Mixture adj screw problem?

CO (carbon monoxide) high at 1500RPM, 2500 passes what's my problem and how do I fix it?

Please help OB1...

stlrj · 03-29-2007, 07:37 AM

Is the air pump connected?

schloss · 03-29-2007, 08:34 AM

I hate to be the bearer of bad news.....but I must tell you that you may have broken valve springs. I just went through that same scenario. $4k later I passed smog with flying colors.

fumanchu · 03-29-2007, 09:34 AM

Is your tiiming correct?. An '83 is 5 BTDC IIRC. Check the advance is working right, both mechanical and vacuum signal. You also have a retard function on that distributor, make sure that is functional also.

If you fail CO at low rpm... timing and mixture adjustments will usually get you there, ask me how I know. If all the advance and retard functions are not working in the Dist... tear it apart and clean it up. They get pretty gunked up in there over the years.

Good luck and post your remedy for future searches.

Shawn

emac · emac's Garage

If you turned that screw 45 turns I would guess you are half way to China!!

time260 · 03-29-2007, 11:27 AM

All:
Appreciate the responses:
stlrj: yes, the air pump is connected. Would this also affect hi rpm in case disconnected?
schloss: What are other symptoms have you noticed, if this is the case, and how can I be sure? Major proposition, it is.
fumanchu: yes timing and idle was adjusted - timing to be between 4 &5 BTDC. Idle betw 900-950 , and its not hunting. Mixture was the one I was asking about, seems oK initially, until the last adjust.
emac: Not close to China, reminds me of that commercial piercing through earths crust and landing in China...

Keep it coming, appreciate
time260

schloss · 04-01-2007, 06:18 AM

time

have you done a leakdown test? The numbers will tell the tale.

My car lacked power and wouldnt rev worth a $hi!. I replaced the injectors, cap,rotor, fuel filterplugs ,wires and o2 sensor and ran 5 gallons of blue moly and chemtool through it befor i had the leak down test. the 4k was painful but my car runs great now.

time260 · 04-01-2007, 06:41 AM

schloss:
No, I have not done a leakdown test. What numbers should I expect and what is the expected difference between valves? This is CIS 1979, different from our 83s. Thanks.

xpensivewino · 04-01-2007, 08:27 AM

The problem is not your car but the stupid state we live in. I have a 78 SC, I went with headers and a sport muffler and the old "$100" smog test and now I'm a happy California driver with 25 more horsepower and lower oil tempature. That's a real bargain at $50 bucks a year !!!!