HC Emissions Problem

[ozzi]

My 87 Camry SW has traditionally had a hard time passing the Texas HC Low Sp Test.
It comes in at the upper limit, 167 ppm. It is that time again and I'm looking for help.

Other tests on CO, CO2, and NOx are quite good.

I had the fuel system "cleaned" 2005 but it did not show a bit of improvement.

The magic of Rx7 does not even help.

I tune it with new plugs, and oil change just prior to the test.

It has 254K on the original cat converter, but has never been contaminated or damaged. Is it due to be replaced?

[Ancientwolf13]

Yes I would replace it with that much milage. I would also suggest an O2 sensor if that hasn't been replaced yet also. What is Rx7? Dry gas also helps if Rx7 isn't a type of that type of additive. Dry gas will lower your emissions temporaily during that tank of gas.

[Doctor J]

Had my 87 wagon failed in test only yesterday. The previous smog have been done by the first owner's frend (who got some problems with the state now); the car was put into 2nd gear and passed the theadmill test (higher rpm sometimes helps to reduce HC). This time the test was performed correctly and the car failed(but not as gross polluter)
Here some info:
Speed HC CO NO
15 132 0.5 670
25 128 0.5 700

Figures in bold are above the limit. The car has 125 000 orig miles (1/3 of it in Mexico);
worn throttle plate shaft; cracks on ignition coil; leak on exhaust manifold gasket,
The oxygen sensor is working and the fuel trim is 3.67V.
At my opinion either misfire under load or vacuum leaks caused the injectors to dump extra fuel once excess oxygen was noted.
Most likely, the cat had burned out.
One of my customer's 89 Camry with 130kMi, produces 10 times less emissions then mine,however the owner complains of lackof engine power.

[toyomoho]

HC is unburned fuel, check anything that would effect combustion.

[ozzi]

RxP is the gas additive. RX7 is a 4-wheeler once made by Mazda.
RxP has an interesting website. Many impressive claims.

And, BTW, I discovered I did not follow the recommended procedure. Well, next time maybe.

What is DRY GAS?

[Ancientwolf13]

Ok RxP not Rx7. Thats why I couldn't find it .

[Ancientwolf13]

Originally Posted by ozzi

What is DRY GAS?

Dry gas is an additive to get rid of any water/condensation in the fuel tank and in the fuel lines which will cause the gasoline not to burn effectively. Using the dry gas will help it burn better resulting in better emissions.

[ozzi]

My worst fears realized. It flunked the TX emission test on Hi Speed run.
HCs Reading of 168 vs 162 limit Other items.
CO Reading of .52 vs 1.04 limit
NOx Reading of 765 vs 1163 limit
FWIW it was at the limit for Lo Spd Run 167ppm.

I bought an OX sensor but have not had a minute to R&R. The parts guy said though that if it were bad, I would smell it. To my knowlege it has never been changed and I know it has over 100K mi on it. Maybe it's due.

Anyone ever heard of this?
How about a universal cat? Would these readings suggest it would "wear out" in a few months?

Thanks guys.

[Doctor J]

Update: after the catalytic converter was changed the car passed with flying colors.The old cat was ontaminated.Before changing the O2 sensor, test it.
Conclusion:
If all readings are elevated close to the cut points and idle emissions are close to dyno emissions but CO2 is 14% and O2 sensor is working and controling the mixture, change the catalytic converter.
One available at S200 (free shipping)from the parts bin.com

[gumbydammit]

Mine flew through without any cat on it.
How worn is the motor in this car?

Originally Posted by Doctor J

Update: after the catalytic converter was changed the car passed with flying colors.The old cat was ontaminated.Before changing the O2 sensor, test it.
Conclusion:
If all readings are elevated close to the cut points and idle emissions are close to dyno emissions but CO2 is 14% and O2 sensor is working and controling the mixture, change the catalytic converter.
One available at S200 (free shipping)from the parts bin.com

[Doctor J]

Different states have different standards.
Many cars with worn engines had as low HC as 16 ppm (87 Toyota Tercel).
Incorrect timing and disconnected smog devices could result in a gross polluter failure.
If I would set my timing close to 0, and run it on the first gear to boost the RPM, the car will pass also, but it will fail the visual and functional portion of the test.

[ozzi]

It has 254K and in 2004 the head was remfd after I lost coolant and warped the head.
I probably should have R&Rd the whole engine but did not consider it.

I really like the car, obviously, and I want to keep it.
My next step is to ck the OX thingy. I found an OEM cat for $175. That price was much lower than most quotes. I did not get a mfr name.

Is there a name to avoid?

I will ck the throttle plate also. How much wear is too much? 0.010? 0.05?

[Doctor J]

Just change the cat.