Passing CA Smog help - High HCs

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77Matt

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I had my original electric carburetor rebuilt, i was told that was the only option.
Edelbrock says it’s street legal in 50 states- I don’t know when they were officially approved. I had to buy about 10 other parts to make it compatible thought. Just hope it works
 

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Ricko1966

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Edelbrock says it’s street legal in 50 states- I don’t know when they were officially approved. I had to buy about 10 other parts to make it compatible thought. Just hope it works
His was a feedback carb. That's the problem,and to the best of my knowledge ccc carbs on trucks were CA. only
 
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CalSgt

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Hoody

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I'm so glad my K25 is a '75 so no smog needed. I didn't read the whole thread but you might want to look into registering in SD or MT to avoid all this work, time and money just for ca smog. Check out Pennington County, SD Treasurer's site. For MT you create an asset holding llc and is more legit to reg in a business name plus its permanent reg no renewal. Can do it yourself or use a service like dirtlegal.com.
 

tsgs84

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I have a 1977 GMC 5.7L 350 given to me from my dad. It passed smog no problem less than a year ago for the title transfer. Now, it failed CA smog due to high hydrocarbons (3485 ppm @ 15MPH and 1350 @ 25MPH). Also noteworthy is that the technician said the crankcase ventilation hose that feeds into the air cleaner was disconnected (it must have popped off during the inspection). I fixed the PC hose, replaced the air filter, PCV valve, plugs and wires, and rebuilt the quadrajet carb. I was going to tune it to run lean perhaps before the test. I was also going to add the emissions cleaner (not sure if the is just snake oil). It's a project truck that I'm just starting but I need it to pass smog to get moving legally. Should I do anything else before taking it back in considering its almost 100$ each test (no free retests)? and no, moving is not an option lol.
Put good fuel in it, let it run low then load up on isopropyl alcohol (dry gas) on the way to the test. Worked every time for me. Considering that you have no major problems.
 

K5ride

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High hydrocarbons is caused by a misfire. It is unburned fuel. Check anything that would cause a misfire like tune up stuff, over advanced timing, lean fuel mixture, etc. Is your test the two speed idle test or on the BAR 97 dyno? If your GVWR for that year is over 6001 lbs, it is considered heavy duty and a catalytic converter is not required. It will also fail the visual portion of the test, if you add a converter on. You are not allowed to invent your own emission configuration. Driving the vehicle excessively or preconditioning only works for heating up the converter which does not apply to you. It is also not allowed if your smog tech is following proper procedures. Retarding the timing will lower hydrocarbons but you are only allowed +/- 3* from the factory spec at the designated rpm. I would be happy to answer any questions I can. I've been licensed for both smog check and repair in California since 1994 and make these types of repairs daily.
 

77Matt

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High hydrocarbons is caused by a misfire. It is unburned fuel. Check anything that would cause a misfire like tune up stuff, over advanced timing, lean fuel mixture, etc. Is your test the two speed idle test or on the BAR 97 dyno? If your GVWR for that year is over 6001 lbs, it is considered heavy duty and a catalytic converter is not required. It will also fail the visual portion of the test, if you add a converter on. You are not allowed to invent your own emission configuration. Driving the vehicle excessively or preconditioning only works for heating up the converter which does not apply to you. It is also not allowed if your smog tech is following proper procedures. Retarding the timing will lower hydrocarbons but you are only allowed +/- 3* from the factory spec at the designated rpm. I would be happy to answer any questions I can. I've been licensed for both smog check and repair in California since 1994 and make these types of repairs daily.
Thanks - interesting that I can’t just add cats. And yes it is heavy duty. I retarded the timing only by 2 because that is the max now. I’m not sure what the machine was but it was multiple speed test. I changed plus and wires, swapped to a different CARB compliant carb. New air filter and changed oil. There is no egr because of the heavy duty status. Checked all the vacuum lines. I think I’m pretty much ready for to retest once I get the new carb tuned.
 

77Matt

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High hydrocarbons is caused by a misfire. It is unburned fuel. Check anything that would cause a misfire like tune up stuff, over advanced timing, lean fuel mixture, etc. Is your test the two speed idle test or on the BAR 97 dyno? If your GVWR for that year is over 6001 lbs, it is considered heavy duty and a catalytic converter is not required. It will also fail the visual portion of the test, if you add a converter on. You are not allowed to invent your own emission configuration. Driving the vehicle excessively or preconditioning only works for heating up the converter which does not apply to you. It is also not allowed if your smog tech is following proper procedures. Retarding the timing will lower hydrocarbons but you are only allowed +/- 3* from the factory spec at the designated rpm. I would be happy to answer any questions I can. I've been licensed for both smog check and repair in California since 1994 and make these types of repairs daily.
Do you think that a disconnected pcv hose, the one from the valve cover to the air cleaner, could cause such a large amount of HCs? >3000 ppm
 

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The breather hose to the air cleaner would not raise HC. The PCV valve to manifold vacuum would. As far as the timing, you are allowed +/- 3* unless the underhood label states otherwise. Here is a quote from page 18 of the smog check manual - "Pass/Fail Criteria: To pass inspection, the base ignition timing must be within 3 degrees (± 3 degrees) of the manufacturer specification. If it is more than 3 degrees from manufacturer specification, the vehicle shall fail the functional test. Note: If the manufacturer specification provides a range, the 3 degree additional tolerance described above is not allowed. "
 
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Y'all know way too much about smog compliance. Thanks to reading this thread I know more than I ever wanted to know now and I'm almost ashamed to be on the edge of my seat wondering if you'll pass. I know you said moving isn't an option but I would still, just move. 'Murica.
 

JBswth

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I have a 1977 GMC 5.7L 350 given to me from my dad. It passed smog no problem less than a year ago for the title transfer. Now, it failed CA smog due to high hydrocarbons (3485 ppm @ 15MPH and 1350 @ 25MPH). Also noteworthy is that the technician said the crankcase ventilation hose that feeds into the air cleaner was disconnected (it must have popped off during the inspection). I fixed the PC hose, replaced the air filter, PCV valve, plugs and wires, and rebuilt the quadrajet carb. I was going to tune it to run lean perhaps before the test. I was also going to add the emissions cleaner (not sure if the is just snake oil). It's a project truck that I'm just starting but I need it to pass smog to get moving legally. Should I do anything else before taking it back in considering its almost 100$ each test (no free retests)? and no, moving is not an option lol.
I would do those things, then have a PRE-CHECK. That way if it flunks, you won't have to worry about them labeling it a Gross Polluter. When a vehicle is labeled a Gross Polluter, you will have to bring it to a repair only facility and have THEM fix it no matter how expensive it is, then, I have heard, bring it to a state smog referee to be smog checked. If you have a pre-check and it fails, and they tell you what is wrong, you can fix it yourself.

J.B.
 

77Matt

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I would do those things, then have a PRE-CHECK. That way if it flunks, you won't have to worry about them labeling it a Gross Polluter. When a vehicle is labeled a Gross Polluter, you will have to bring it to a repair only facility and have THEM fix it no matter how expensive it is, then, I have heard, bring it to a state smog referee to be smog checked. If you have a pre-check and it fails, and they tell you what is wrong, you can fix it yourself.

J.B.
According to the smog report it was already labeled gross polluter but no one has said anything about where to get it repaired. I did all the repairs myself.
 

77Matt

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Y'all know way too much about smog compliance. Thanks to reading this thread I know more than I ever wanted to know now and I'm almost ashamed to be on the edge of my seat wondering if you'll pass. I know you said moving isn't an option but I would still, just move. 'Murica.
I’ll keep you posted haha
 

DoubleDingo

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According to the smog report it was already labeled gross polluter but no one has said anything about where to get it repaired. I did all the repairs myself.
I think they do that on purpose. Mine shows up as a gross polluter as well, and there has never been any mention of it needing to be fixed by a shop. There is nothing to fix anyhow, everything works, it's just an old truck that stinks to high heaven of exhaust fumes no matter how well it is tuned.
 

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