CA Smog failed - advise please

[SC Schrauber]

Gentlemen,

my 81 Euro SC failed the smog test.

I had the very first smog test done last year with the aux. airpump connected and timing on 5 TDC instead of 25 degrees.
I then removed the airpump and adjusted the timing. I also installed the MSD CD, coil and new wires.

Now I can't pass the smog test (CA).

Here are the readings from last year(with airpump), last week(no airpump, failed) and yesterday(reinstalled airpump, failed).
Ignition, air filter, valves, etc. all in great condition - the car cars great, never touched the CIS.

What should I do? Adjust richer, leaner?



Any help greatly appreciated.

Frank

[ewave]

If you go back to the test done on 11/11/05, it looks like all you had to do was to lean it out a little more (Very simple adjustment on a CIS car). If you do that, CO will drop more (all you need is a .10% drop) and you will pass- As long as they don't visually require the smog pump you should be OK.

[klatinn]

Hi,

The 11/11 test was a tad too rich. The 11/14 was a tad too lean.
When too lean the NOx rises and CO goes to zero.
When too rich NOx goes low and CO rises.
Does the car have an O2 sensor?

Regards,
Klaus

[cowtown]

If I'm reading your spreadsheet right, you failed on CO on 11/11 (NOX was OK), and failed on NOX (CO was OK) on 11/14. On 11/14 the car was running lean, with only 0.01 CO. Was the car hotter on 11/14 when tested?

Richening the mix will raise CO and HC, and lower NO. Leaning will lower CO and HC, but raise NO.

EDIT - klatinn beat me to it.

[Danskman]

What county in the bay area do you reside?

[SC Schrauber]

Paul, Klaus, cowrtoen, Mike

my car has no oxygen sensor.

I live in Sunnyvale, Santa Clara County.

Both times (11 and 14th Nov) car was nicely hot after a 10 miles hwy run.

So if I understand correct, if I keep the airpump in (for now) and richen the mix, that will bring NOX down (what I want) and raise the CO level (I have plenty of room there)?

Frank

[klatinn]

Hi,

So if I understand correct, if I keep the airpump in (for now) and richen the mix, that will bring NOX down (what I want) and raise the CO level (I have plenty of room there)?

Yes. What's curious is that the installation of the air-pump leaned out the mixture.

The only explanation I have for that would be that during the no-airpump test the engine was not fully warmed up and it was running still with the WUR lowering the control pressure (making it rich). Make sure the engine is fully warmed up before the test.
If you know somebody with an LM-1, disconnect the air-pump and adjust for Lambda 1.0 with the engine running. Also test under light load (2500 RPM, 2nd gear with foot lightly on the brake).
I just did that procedure my daughters CIS VW golf and it passed with flying colors (all values less than half of average). This with an engine with 170,000 miles.

Regards,
Klaus

[cbeers]

Frank,

I can't help with diagnosing your smog issues, but do you know about RMG there in Sunnyvale? Right behind Bugformance on El Camino and Mary. VERY helpful guys and Bob will put your car on his smog sniffer, check it out, tweak if required and send you around the corner for a smog check.

Just something to consider

-Chris

[SC Schrauber]

Klaus,

interesting thoughts. However the engine was hot on both days. I never touched the mixture screw. Timing and valve adjustment are fine. Here is what I figured:

Since the disconnected air pump does obviously not add air to the mixture, the mix must be richer, thus creating higher CO and lower NOX values. I agree this can be caused by an still active WUR however unlikely because of the high engine temperature.
Once the pump is back on, it leans out the entire mixture, creating lower CO and higher NOX.

I'll give your method a try. Many thanks.

Frank

Originally posted by klatinn
Hi,



Yes. What's curious is that the installation of the air-pump leaned out the mixture.

The only explanation I have for that would be that during the no-airpump test the engine was not fully warmed up and it was running still with the WUR lowering the control pressure (making it rich). Make sure the engine is fully warmed up before the test.
If you know somebody with an LM-1, disconnect the air-pump and adjust for Lambda 1.0 with the engine running. Also test under light load (2500 RPM, 2nd gear with foot lightly on the brake).
I just did that procedure my daughters CIS VW golf and it passed with flying colors (all values less than half of average). This with an engine with 170,000 miles.

Regards,
Klaus

[SC Schrauber]

Bugformance is one of my favorite shops.
I'll check with Bob@RMG and see whether he can, like Klaus said, adjust the Lambda.

I actually recall now that when I got the car last year the spark plug faces were too light (too lean), after I disconnected the air pump it was better (light brown or "rehbraun" as we say).

I guess I have to richen the mix for now, pass the smog test, disconnect the air pump and lean the mix out. How much does one click on the distributor richen or lean the mix?

Frank

Originally posted by cbeers
Frank,

I can't help with diagnosing your smog issues, but do you know about RMG there in Sunnyvale? Right behind Bugformance on El Camino and Mary. VERY helpful guys and Bob will put your car on his smog sniffer, check it out, tweak if required and send you around the corner for a smog check.

Just something to consider

-Chris

[ewave]

I actually recall now that when I got the car last year the spark plug faces were too light (too lean), after I disconnected the air pump it was better (light brown or "rehbraun" as we say).

The air pump injects air into the exhaust system... It should have NO EFFECT on the AF mixture in the combustion chamber, and would not effect the color of the spark plugs....

[SC Schrauber]

Originally posted by ewave
The air pump injects air into the exhaust system... It should have NO EFFECT on the AF mixture in the combustion chamber, and would not effect the color of the spark plugs....

Well, in that's the case I'll have to richen the mixture anyway, right! Thank you for the input.

Chris,
I talked to Bob this afternoon. He'll have the issue fixed in no time tomorrow morning. Thanks for you the excellent lead. Great shop!

Best,
Frank

[Joe Bob]

Tune the car with a analyzer and take it back. Adjusting the mix with a hex key turning 1/8 turn at a time.

My 3.0 euro passed w/o a cat MANY times....

[SC Schrauber]

Gentlemen,

after richening the mix just a tack and allowing the engine to cool down a little after the drive to the test station I passed smog.

Thank you all for your valuable input.

Frank

[cowtown]

Whew! Squeaked under the NO limit.

[anthony]

Both times (11 and 14th Nov) car was nicely hot after a 10 miles hwy run.

My car doesn't warm up after a 9 minute run. I don't get full operating temperature until after 20 minutes of driving.