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Discussion Starter #1
What the heck does an O2 sensor do on a carburated Sammi? I understand on EFI engines, the reading will change the injection pulses but how about one of these? Is there something electrically driven on the carb that'll change the air/fuel mixture? Or does it change the ignition timing? Or was it put there for looks and to make the EPA happy?

Phil
 

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Very good question. I thought the same and when I swapped in a 1.6L the header did not have a spot for the O2 sensor so I obviously didn't install it. So far it runs like a charm!
 

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Discussion Starter #3
Very good question. I thought the same and when I swapped in a 1.6L the header did not have a spot for the O2 sensor so I obviously didn't install it. So far it runs like a charm!
Thanks again PP. It must not be TOO important then.

I found online PDF copies of a 1988 Samurai service manual (maybe from a link here... been too many Sammi sites to remember exactly) and was reading through it an hour or two ago. What I learned is the ECM controls a solenoid in the carb, cycling it 16 times per second. When it goes down (ECM signal) it opens an air passage making the mixture go lean. No signal makes it go back up and rich.

I've had other vehicles that performance improved with a new O2 sensor if the one it replaced had over 60,000 miles. The one in our Sammi is probably original (180,000 miles) and since it's easy to get to I was considering installing a new one.

From your experience it seems the ECM has a pretty good "default" program. Do you have to smog yours?

As part of the condition of sale, I had the seller smog this one but I know enough about engines to also know that it couldn't have legally passed the visual test. Which makes me wonder about the sniffer test. For our off-road-only use I won't need it to pass smog again, but as cheap as O2 sensors (usually) are, it seemed like a cheap & easy "performance" upgrade.

So I coulda/shoulda found that manual before posting here, but if I'd done that you wouldn't have told me how well it runs with NO sensor.

Phil
 

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Mine is running a Hyundai Pony carb with no electronics at all. THere is a bundle of taped up wires under the hood that are just decoration. It is probably for the best seeing how much mud and water I drown the poor thing with, the less electronics the better!
 

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Discussion Starter #5
Mine is running a Hyundai Pony carb with no electronics at all. THere is a bundle of taped up wires under the hood that are just decoration. It is probably for the best seeing how much mud and water I drown the poor thing with, the less electronics the better!

That's good to know. I had given thought to putting a different carb on and wondered how the ECM would react. Most cars of that vintage would get a "check engine light" with that much disconnected and then wouldn't give spark.

This one runs ok but I've seen where these stock carbs have problems.

Phil
 

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That's good to know. I had given thought to putting a different carb on and wondered how the ECM would react. Most cars of that vintage would get a "check engine light" with that much disconnected and then wouldn't give spark.

This one runs ok but I've seen where these stock carbs have problems.

Phil
I have a weber sitting in my garage that I had on my 1.3L. It worked well but I just didn't switch it over when I dropped the new engine in (it ws complete).
 
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