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Ca smog fail. Help!

Sorry- forgot about this post.
I advanced my timing by cutting the ears of my distributor and manually moving it.
Yes this is not a full timing advance as its controlled 1/2 way by the cps.


I'm pretty sure the timing is completely controlled by the crank sensor. The sensor in the distributor is really only used to figure out which stroke it's on.
 
So I finally had a couple minutes and I threw some sea foam in the intake and got a bunch of white smoke. Some people argue it’s good blasting out carbon and others say it just looks cool. Either way it’s done and there was a tons of white smoke and with that I discovered an exhaust leak. A perfect looking weld is spitting out exhaust so now I have that to fix next time I have a few hours. Could that be my problem or just part of the problem. Seems like from deductive reasoning that if exhaust is leaving the manifold before it reaches the o2 sensor then the o2 sensor would read less oxygen than is really present and would drop the amount of fuel to the engine resulting in a lean condition. Does that sound right or am I off in my hypothesis? Either way it’s getting fixed next time I have time.


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The O2 sensor really gives a percentage of oxygen, and not really an amount so loosing exhaust shouldn't affect it. However, keep in mind that the exhaust is not a steady pressure, but rather pulse of pressure and slight vacuum between pulses. So aAn exhaust leak can actually suck air into the exhaust, and yes that can present extra oxygen to the O2 sensor which screw up your NO numbers.
 
I found an exhaust leak once with seafoam. Manifold cracked in a couple of places.

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So 2 years ago I had similar results with my 88. All good just a bit too high on the NOx @25mph. I ran some seafoam found another exhaust leak. Just a rusty clamp after the CAT this time. Ran some good FI cleaner and adjusted my TPS (yours is not adjustable). Second test passed.

Fix your known leak first.

Then you can test the cat using an IR thermometer to measure the inlet and outlet temps once warmed up to operating temp.
 
It’s been awhile since I’ve had any free time to do anything. I finally got a few hours today and swapped out my cracked manifold for a new one. Also changed o2 sensor and still failed smog. This time for high NO at low speed. The other two times it was high speed. I’m pretty frustrated and lost right now. Any suggestions or know of a place that can “smog” this thing in north San Diego county? I think I’ve given the state and smog companies enough money now. So to keep a record. Engine had good compression but I don’t remember the numbers. New radiator and cap, thermostat, water pump, cleaned injectors, spark plugs, wires, cap and rotor, oil and filter, catalytic converter, and exhaust manifold and o2 sensor(Ntk installed after sea foam). stock height and tires. Sea foamed gas tank and intake and drove for an hour before this latest smog.
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Again, I'd get an IR thermometer and check the inlet and outlet temps of the Cat. Make sure there are no exhaust leaks all the way to the exhaust tip.
 
With a zero oxgen result, I wonder how there can be an exhaust leak down stream of the O2 sender upstream maybe as that will fool the O2 sensor to go rich. that richness will result in HC burning with oxygen in the cat, thus no O2 out the exhaust.


what causes NOx formation? High temps! too high a compression by design or carbon build up, to advanced timing. higher octane fuel may help if this the case, as this will reduce heat if the low octane was detonating and your know sensor is not retarding the timing. So check the knock sensor!

too hot a heat of a spark plug can also cause hot spots, making NOx, try a cooler plug if you have a hot plug.

a very lean mixture can cause hot cylinders. clogged injector, intake leak? check in injectors for flow and spray pattern. reading the spark plug or pulling one injector connector off at a time while at idle noting change in idle speed may also help locate which cylinder has an issue.
flammable spray carb cleaner or starting fluid will pin point intake leaks.

good luck
 
Update. I passed two days ago. Yew! I checked everything I could think of and everything seemed good. Since the general consensus was that it was running too hot, I took advantage of the past weekend’s rain and cold weather in Southern California and went to get tested first thing in the morning with 50 degree weather and 20knots of wind. It passed barely, but it passed.


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