- Thread starter
- #21
Welp, seems like the air pump is not working. It’s not flowing at all. Disconnected the vtv and waited and still no air flowing. Stay tuned.
1985 failed smog with results
- Thread starter mbxmikey
- Start date
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The air pump diverts it’s flow to the exhaust pipe at higher RPMs. What’s curious is that your idle O2 is good - showing that the air pump is working at idle, but your O2 at 2600 RPMs is almost zilch.
On my test, same engine, my O2 at 1700 RPM was 2.2.
Maybe the check valve at the exhaust pipe fitting is plugged shut. Check it.
On my test, same engine, my O2 at 1700 RPM was 2.2.
Maybe the check valve at the exhaust pipe fitting is plugged shut. Check it.
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- Thread starter
- #23
I have something stumping me. The choke breaker circuit seems to be open to atmosphere where it ties into the air cleaner. It’s a vacuum leak and it’s not closing the choke circuit think on the backside of the carb unless I plug that line before it goes into the air cleaner. What am I missing? Thanks
- Thread starter
- #25
Im going to try to take it in this week for another sniff. I traced all the hoses again and found that the metal hose routing in my tree is a little different from what the 2f manual shows so I had some hoses between the carb and HAC routed incorrectly. She’s running better. I figured I would run a tank through her first and see how mileage looks then test it if stuff has improved. Stay tuned.
- Thread starter
- #26
So I got her sniffed again. We didn’t print out the results but the gist of it is the HC was at 10% at 2500rpm the first time I went per the results I posted and now they are at 5%. Talking to the smog guy and he seemed pretty confident that I am close enough now that he thinks I could adjust the carb to lean it out enough to pass that test. The HC at idle was still the same as the first test. Making progress. So plan is to try to lean out the carburetor more, put in fresh oil and filters and maybe some additive to the fuel. Any other thoughts?
Thanks for all the help so far.
Thanks for all the help so far.
Higher hydrocarbons are the result of incomplete combustion. Some fuel is not getting burned. (Rich).
Make sure the air cleaner filter is brand new so it won’t restrict air flow, and yes, changing the oil before a smog test is always recommended.
The engine always has a bit of blow by, and if it’s blowing by old contaminated oil, that stuff ends up in the exhaust stream too- raising hydrocarbons.
Make sure the air cleaner filter is brand new so it won’t restrict air flow, and yes, changing the oil before a smog test is always recommended.
The engine always has a bit of blow by, and if it’s blowing by old contaminated oil, that stuff ends up in the exhaust stream too- raising hydrocarbons.
There is a restriction orifice that should be installed in that line that connects to the air cleaner that is not shown in the picture you posted. In the picture below, it is shown as opposing triangles "pinching the tube". In reality it is like a tube fitting union. It is shown in parts diagram (bottom) as part number 90412-05001. In short, this is not considered a vacuum leak but it is an introduction of air that bypasses the carburetor that is "engineered" into the system.
