Failed Smog: 1980 242 CA

Hello
My car failed Smog for emissions, vacuum leaks and timing. I fixed timing and vacuum leaks and retested and these were my results.
The smog guy told me I should get a tool that I forgot the name of to test the air fuel ratio. Does anyone know the name of that tool? My oxygen sensor is new but maybe it's faulty.
Please help I love my car and hate CA emissions standards. I'm sure some of you had similar experiences.

Thanks
Emilio

Afr.

Is your timing set back to factory specs?

How do spark plugs look?

nox is thru the roof! either lean or bad cat. airleaks will cause lean. Listen around with a hose in your ear.

A properly functioning cat will use most of the o2 in the engine's exhaust, so the number you should expect on the readout should be very close to zero, like 0.7% or so.

Messed up AFR (too lean) would make the cat struggle to use up all the oxygen and give elevated numbers, but I doubt they'd be that high. A vacuum leak could definitely do it, as could a pre-cat exhaust leak.

And IIRC, CO2% should be around 17%, indicating a good, efficient burn. 10% is pretty low, indicating it's not running very efficiently. Though again, a vac/pre-cat exhaust leak could mess up this number.

I'd say a good tune-up including cap/rotor/plugs/wires (to help CO2, good basic maintenance regardless), making sure you've got good fuel pressure (low fp = lean = high nox), no vacuum leaks (too much O2 and the cat can't scrub nox correctly/at all) making sure your timing is on the money (overadvanced = higher combustion chamber pressure = higher nox), ensuring that there are no pre-cat exhaust leaks (this will introduce O2 into the exhaust, making the cat not work correctly, raising nox) and changing the oil (to help HC).

If that doesn't do it, I'd check your CO and if that doesn't help, start shopping around for a new cat.

My NOx readings were through the roof with the other readings below the max allowable. The egr was clogged in the intake manifold where the egr tube connected to. I knocked out the blockage with a nail and cleaned up with carb cleaner and when I went back for smog it passed all tests in about 5min. NOx was a good amount below the max allowable limit.

This was on my 77 242 with original cat and a 49 state car.

eparayno said:

The egr was clogged in the intake manifold where the egr tube connected to.

Click to expand...

^^^Yes, definitely test/service the egr if it's so equipped. Forgot to mention that one.

eparayno said:

My NOx readings were through the roof with the other readings below the max allowable. The egr was clogged in the intake manifold where the egr tube connected to. I knocked out the blockage with a nail and cleaned up with carb cleaner and when I went back for smog it passed all tests in about 5min. NOx was a good amount below the max allowable limit.

This was on my 77 242 with original cat and a 49 state car.

Click to expand...

I do not think I have an EGR valve. It looks like an ugly vacuum thing sticking off the top of the engine correct?

Baileyswhite said:

^^^Yes, definitely test/service the egr if it's so equipped. Forgot to mention that one.

Click to expand...

I was kind of excited to clean this thing... and reduce some crap from my car but there doesn't seem to be one on my car. The way it looks in the manual I cannot locate.

heres a photo:

The egr connects to the intake manifold by the firewall. Look for a metal tube attached to the manifold, if you have egr you can test it by removing the hose attached to the valve and apply vacuum. The engine will want to stall if the egr is functioning. When I did that to my car the idle didn't change at all. I applied vacuum(used my mouth to suck through spare vac line) with the engine off and I heard the plunger open and shut, it held open too when I held my thumb over the hose. If you have a mityvac or similar that can be used to check and hold vacuum then that works too.

Of course if your car does not have egr then I don't know.

If your car still has an emission control information sticker under the hood/on the strut tower/in the engine bay somewhere it will say whether you have one or not. It will say "EGR" on it. If not, then you don't have one.

No EGR.
Next guess?

I don't know how your car has been maintained or how it's running, so some of this may be irrelevant, but that's for you to decide--from the top:

Baileyswhite said:

I'd say a good tune-up including cap/rotor/plugs/wires (to help CO2, good basic maintenance regardless), making sure you've got good fuel pressure (low fp = lean = high nox), no vacuum leaks (too much O2 and the cat can't scrub nox correctly/at all) making sure your timing is on the money (overadvanced = higher combustion chamber pressure = higher nox), ensuring that there are no pre-cat exhaust leaks (this will introduce O2 into the exhaust, making the cat not work correctly, raising nox) and changing the oil (to help HC).

If that doesn't do it, I'd check your CO

Click to expand...

Also, how's your O2 sensor?

Baileyswhite said:

if that doesn't help, start shopping around for a new cat.

Click to expand...

Guys I can't deal with repairing mystery emissions problems. I am going to buy a catalytic tomorrow. What are the chances, with the results I posted before, that a new cat will solve all my goddman life, problemz?? I drive my car without tags even though my cars registered it's just not smogged and I don't wanna get arrested so I need to figure this one out.

(drug forum talk)
Swim said he bought a new cat, bolted it in, passed smog, pulled it out, put it on a shelf and waited two years then did the same. I have hecka cats they just all don't seem happy enough to eat my ****ty exhaust fuss. Please opinions, brand new cat, brand new smile?!