Passing CA Smog help - High HCs
- Thread starter 77Matt
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- 1977 carburetor fuel systems smog
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evlblkrfl
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IDK??? That's a picture of the manual that came with my 1400
ButchM
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These may help also.
76n559
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Save money and time. Get a voucher from valley clean air. I got $850 emissions and smog repair. Also apply for $1200 on ca dmv repair since you already failed
DoubleDingo
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Taxpayer money that doesn't need to be spent. If it'll cover the carb, great, but no way it's going to cost over 2k to get it to pass. And if one applies for all that money and then pockets the rest, we all lose, and we are already being squeezed out of money by big gov for we don't have to give. It won't even cost 850 to pass.
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Did you get it to pass smog with the new Qjet carb? I got the same one you did from National Carburetor. The truck actually starts and idles better than with the Edelbrock 1400 I originally had on it, and I haven't made any adjustments yet. We'll see once I'm able to drive it, but so far, I'm happy with it.
I also installed the electric choke conversion kit from Mike's Carbs, and it was really easy to install and adjust.
77Matt
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No, it runs like crap. I tried adjusting and had some other shade tree mechs look at it. The EB was way better but CA says nope. This one is beyond my capabilities and I am planning on taking it to a QJ specialist. I might just let CA win this one, sell it and buy an exempt truck
DoubleDingo
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If you got a new one it shouldn't run worse or need adjusting, except for maybe idle speed and fast idle speed. I am going to reread the thread to see all that you've done thus far.
DoubleDingo
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Read through the thread, what plugs did you use? What did you gap them to? What is your timing set to? 3 degrees different than it was doesn't provide an accurate answer, need numbers. You have not shown us one photo of your engine bay so we can decipher what you have. Post up some pics of under the hood. Have you replaced all of the vacuum hoses? Is there a vacuum leak? What does a vacuum gauge read and do when you hook one up to tune the engine? Is it high vacuum? Is it low vacuum? Does it bounce? Is it steady? What did the old plugs look like when you took them out? If you don't have all the egr stuff, this should pass no problem if it's properly tuned. Smog pump, does it have one? Is all the plumbing to it correct if has a smog pump? If I recall correctly, it has to pass emissions for you to sell it, so you may as well fix it and keep it.
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Man. Sorry to hear that. I was hoping yours performed like mine. As DoubleDingo mentioned, it would be great to get some more specs on what is going on. I'll relist a few:
* Vacuum reading: Value and is it stable or bouncing around
* Timing: Value (unplugged from port vacuum)
* Spark Plug: You may want to pull one or two to get a reading. Maybe post a few close up pics
* Fuel pressure: Do you have a gauge? If so, it would be good to check fuel pressure going into carb
We'll try and help (remotely) as best we can. A QJ specialist isn't a bad idea. You may also call National Carb to see if they have feedback. They may be able to help diagnose if it is carb or other.
Hope you stick with it. It can be solved and we'll all learn as a result.
77Matt
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It ran fine on the EB so I don’t think it’s spark or fuel. Timing was offset to the max allowable by ca. There is a ton of exhaust so I thought it was running super rich and couldn’t dial it back. I figured the hinge pin was stuck and not dropping in. When I opened it up it was th opposite, the hinge pin didn’t have the little hook to hang on the float. So after fixing that and adjusting the float, I was back at square one. The vacuum set up is slightly different between the 2 carbs so that could be a clue. The new carb does not have one of the ports the old carb had. There’s a port that goes from the carb body to a control valve and then back to a 2nd vacuum break. I tested for the correct vacuum type and Td off another and seems to be correct. Basically with the new carb, there’s a ton of exhaust and it runs louder and rougher. I can send some pics later. Thanks!
DoubleDingo
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Timing is not set by what CA wants, you set it to what the engine likes, same with the carburetor, and you use a vacuum gauge and timing light for best results. Correct plugs and proper plug gap is critical as well. You still need to answer some questions and post some pics of the engine. We are trying to help you out, but without information or photos of what we are trying to help with, all of us are just throwing darts in the dark. Can't hit the bullseye when you can't see the danged dartboard.
ButchM
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Testing "hot" (as in drive around for 20-30 minutes) is for a few reasons:
- If it has cats, it lets them get up to operating temp (minimum 600 deg F if I recall correctly) so that they're doing their conversion thing and not passing along unburned fuel = high HC on test.
- It lets the engine warm up enough the choke is fully open... partially closed choke = high HC
- Warm engine will, over period of time ( 20-30 minutes is what I was told a long time ago), "burn off" the gasoline that accumulates in the oil. This gasoline gets in the oil when the choke is on due to overly rich mixture needed for cold engine operation and the excess/unburned gasoline passes by the rings into the crankcase. As the engine warms and vaporizes this gasoline in the crankcase, the PVC removes and burns it. This equals extra fuel introduced into the combustion process = higher exhaust HC.
- Lastly, but by far not leastly. A short preamble: The engine needs to be getting up to near 200 deg F as normal operating temp, if not replace the thermostat. Over the years many people (myself included) have put in lower temp thermostats as a way to get our rigs to run cooler, make more power etc. This is BAD BAD BAD for emissions testing.
-- A fully warmed-up combustion chamber is efficient at burning the air/fuel mixture. Not fully warmed-up chamber doesn't burn all the fuel = higher HC. This is a major reason the engine should be at normal operating temperature 195-200 deg F (and don't some of you keyboard mechanics ****** me on a few degrees, the idea/premise is proven).
-- The same idea holds for having the proper spark plugs as someone mentioned. A plug that is "too cold" will not light off or burn the air/fuel charge properly/completely = higher HC. You may consider going one step hotter plug for the test. A hotter plug may help burn more fuel and help with the higher HC (anyone else have any ideas on this?). I would change them out after the test though.
- All engines I recall working on had ported and/or thermal switch controlled vac to the distributor. Someone mentioned setting advance where the engine ran best... good for normal operations, not for smog testing. Set it where the emissions sticker says, gotta make it pass at this setting. If/when they put a timing light on it and it is off the factory spec.... automatic ding, maybe fail if your guy is named Richard.
Hope this is of help.
Butch
