I spent a good portion of my Saturday morning and afternoon at the smog test station trying to pass with my new Weber 32/36 carb that I've been fiddling with for the past week or two since I finished my installation (including EGR bypass). When I first went through for the test, I hit almost 3 times the CO limit which suggested that I had a pretty rich mixture. During this test my hydrocarbon ratings were over the threshold, but just barely. Naturally I decided to lean out the mixture big time and re-test, but doing so jacked my hydrocarbon ratings through the roof (almost 5 times what is acceptable!). For the next ~2 hours I made small adjustments to mixture and timing (I didn't have a timing light so I was guessing) until I finally passed. It only took 6 trips through the station!
In the end, I was able to achieve ~0.5 CO rating (must be less than 1 to pass the test in OR) and a hydrocarbon rating of ~130 (needs to be less than 220 to pass in OR). I learned that hydrocarbon ratings are very sensitive to the engine timing and that the mixture/CO issue was relatively easy to resolve. I was just thankful that they didn't ever decide to pop the bonnet and check out what I have going on under the hood - that would have failed me for sure!
Next time I get a chance to check my timing, I'll add to this post to clarify where I ended up because when I went in to get the test, I was at about 13 degrees BTDC. I have a feeling that I ended up closer to the manufacturer spec of ~5 deg BTDC.
Smog test(ing my patience)
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Smog test(ing my patience)
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- Petros
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Re: Smog test(ing my patience)
Interesting it will pass with a Weber all and all the other stuff stripped off. You should put your timing back up to 10 deg BTDC, or you risk burning exhaust valves. I had that happen several times until I advance the timing (it allows more complete burning before the valve opens and results in cooler exhaust gas temps). Just remember to retard the timing next time you need to test it.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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Re: Smog test(ing my patience)
I don't have anything to add to this thread - but I wonder what kind of emissions Goldie is emitting since the Weber addition and all emission stuff (save the CC) has been removed and with the ignition now at 10° BTDC?
Just curious. It took a reman carb, EGR cleaning, new EGR modulator-CC-dist vac advance-TVSV-PCV, and miles of tubing to pass back in 2005. Pre-1995 vehicles are now exempt.
Tom M.
Just curious. It took a reman carb, EGR cleaning, new EGR modulator-CC-dist vac advance-TVSV-PCV, and miles of tubing to pass back in 2005. Pre-1995 vehicles are now exempt.
Tom M.
T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
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"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"
"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain
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Re: Smog test(ing my patience)
The testing is only done at a few steady state conditions, and easily met by a properly jetted and adjusted weber. The manufacturer was required to reduce total emissions over a whole driving cycle, which they do not test in the yearly testing. That is why all the other equipment is necessary, and why it is illegal to remove or tamper it it, even if the car passes a yearly sniff test. They are supposed to be inspecting that all the equipment is present, so if they do that you will have to install it and at least make it look like it is in working condition. I doubt they would even notice that you have a weber on it if you have all the miles of hose and vacuum devices all dummied up but still installed.
Of course anyone who attempts this would be breaking the law. So this is just FYI, and for off-road use only of course.
Of course anyone who attempts this would be breaking the law. So this is just FYI, and for off-road use only of course.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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Re: Smog test(ing my patience)
I finally had the opportunity to check the timing since I took the Terjunken in for smog tests. Turns out that I had to adjust the timing to 5 deg BTDC to pass emissions (it was previously set to 13 deg BTDC). At the moment, I've advanced the timing to 10 degrees!
So for all you Oregon T4WD drivers, note that a lean mixture and ~5 deg timing with a Weber 32/36 will get you past the smog tests:) Also, see
http://www.tercel4wd.com/forums/viewtop ... f=7&t=6118
This link will describe the concept of using the vacuum advance in different ways to optimize your combustion from an emissions perspective. When I passed the Oregon DEQ smog test, I did so with the Weber vacuum advance port (right side port on the base of the carb) connected to the distributor vacuum advance. This is not the way the carb should be set up if you want to optimize fuel economy (as the above link describes).
So for all you Oregon T4WD drivers, note that a lean mixture and ~5 deg timing with a Weber 32/36 will get you past the smog tests:) Also, see
http://www.tercel4wd.com/forums/viewtop ... f=7&t=6118
This link will describe the concept of using the vacuum advance in different ways to optimize your combustion from an emissions perspective. When I passed the Oregon DEQ smog test, I did so with the Weber vacuum advance port (right side port on the base of the carb) connected to the distributor vacuum advance. This is not the way the carb should be set up if you want to optimize fuel economy (as the above link describes).
Last edited by deejay1272 on Tue Jan 11, 2011 10:22 pm, edited 2 times in total.
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Beefsteak when I'm hungry, whiskey when I'm dry
Greenbacks when I'm hard up, heaven when I die
Beefsteak when I'm hungry, whiskey when I'm dry
Greenbacks when I'm hard up, heaven when I die
Re: Smog test(ing my patience)
Hello,
You should put your timing back up to 10 deg BTDC, or you risk burning exhaust valves.
I had that happen several times until I advance the timing .It allows more complete burning before the valve opens and results in cooler exhaust gas temperature...
You should put your timing back up to 10 deg BTDC, or you risk burning exhaust valves.
I had that happen several times until I advance the timing .It allows more complete burning before the valve opens and results in cooler exhaust gas temperature...
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- Top Notch Member
- Posts: 403
- Joined: Thu Oct 08, 2009 9:20 pm
- My tercel:: 1985 Navy Blue Tercel Wagon SR5 4x4 now with Weber 32/36!
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Re: Smog test(ing my patience)
Thanks, Imran. I've corrected my error above. I am running at an advance timing of 10 deg BTDC to avoid burning my exhaust valves.
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Beefsteak when I'm hungry, whiskey when I'm dry
Greenbacks when I'm hard up, heaven when I die
Beefsteak when I'm hungry, whiskey when I'm dry
Greenbacks when I'm hard up, heaven when I die
- T4WDgambler
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Re: Smog test(ing my patience)
Woohooo thank you for this post! I went today (Oregon) and had a failure reading of 407 and 472 HC and 5.45 and 5.77 CO should be less than 220 HC and 1 CO... now off to get the timing to 5 deg BTDC and see if that works, also would be nice to see where I’m at now.