I recently acquired a 1979 SR5 with the 20R and I'm currently working on passing smog in arizona. insurance or registering it in a non-smog area aren't an option for me as I don't know anybody outside the area and this is my primary vehicle. I'm going to try to tune the carburetor but I'm new to old cars and don't know where to start. can you give me any advice on how I should tune this to pass or if I should just bring it to a shop and have them tune it? I uploaded my smog test and aside from replacing the hose the numbers don't seem like they're too far off. any advice will be greatly appreciated!
Does "AIR SYSTEM - FAIL" mean the air injection system was removed?? If so, I can see why you'd fail the sniffer test since the air injection is meant to inject air into the exhaust stream to burn some HC and CO in the exhaust port and give the CC air to further convert excess CO and HC into H20 and CO2.
This was originally sold in California and had all of the California specific emissions equipment removed. As far as I know all of the other emissions equipment should still be there, but I’m fairly unfamiliar with these engines so I can’t be sure. The inspection note state that the “pump has no hoses on it 4100” so hopefully all I need to do is replace them.
It's hard to tell with that plug wire holder there but, it looks like the engine has a non-smog legal header, without air injection manifold mounts? If so, you'll need to find a smog legal header or oem exhaust manifold, air injection manifold, in addition to the hoses. I'm guessing that means a trip to the junkyard...
A trip to the junk yard or to the "want to buy" section of the various sites dealing with such parts. As for not passing a smog test your CO looks ridiculously high. Before farting with the jetting rule out any misfires. Those Weber adapters are notorious for leaking. You'd be best off getting a manifold designed for that carb. Make sure the float level is within spec as well. Come to think of it, if that is a China Weber knock off..... I see you do have the air injection pump in place, with a belt, is it hooked up completely? Mr. Dinkleman is right about what it is for. Properly operating air injection with a healthy cat could clean that up. One thing I'm curious about is the final test is worse than the precondition test, warming the exhaust up in any case should improve the test results. In any case, not knowing just what the previous owner did with the engine can have you chasing your tail. Make sure there are no issues with the engine. Good plugs, wires rotor and cap. If you have points be sure they're properly adjusted. Vacuum leaks cause more problems than I care to remember. Even a therostat that stays open can cause issues. Try to find out what, if anything, has been done to the engine before you even start attempting any tuning. So there's an aftermarket carb, may or may not be a Weber, and headers. Those may or may not cause problems with a stock engine, but with more parts the possibility of test failing emissions increases a lot. Pull a plug and look at the piston, 20R or 22R piston? The 20R block can be punched out to 92-93mm. Port work can kill emissions. Aftermarket cams can send you into the deep end. Do a little digging. And, of course, having all the proper emissions equipment installed and in good working condition helps. There are other factors not even related to your vehicle that can have effects on your smog test, like the technician and the condition and calibration of the shop's equipment. Just to prove a point I went to 4 shops, one right after the other, and took the results to the BAR office. 4 shops, 4 substantially different sets of results. They didn't like it much at the BAR office. Yeah, the CA smog program has been my windmill for some time.
