Help CA smog fail

[knunn911]

I have 1976 911S, 2.7L CIS. Stock motor. I have an LM-1/ aux box. I set the mixture at 14.7AFR at idle, smog pump belt disconnected. The timing and the idle was set at factory settings. When I connected the smog pump belt the AFR jumps up to 18.2 AFR at idle.
I when and had the P-car smog and it fail the CO(%) at 15 mph was 3.97 (max is 1.41) and at 25 mph 2.56 (max is 1.21). Any suggestions? What am I doing wrong setting the mixture for smog?

Please help,

Thanks,

Ken

[ToddM]

I take it moving is out of the question?

[knunn911]

I like Ca, but I hate the smog laws.

Ken

[stlrj]

Seems like your LM-1/ aux box is way off as the CO test numbers indicate you're mix is way rich.

[the]

1976 in Cal., as Maxwell Smart would say, "Missed it by that much."

[Porsche-O-Phile]

The over-regulation in CA is slowly making it unlivable.

I'm SO happy I have a pre-'75 911 (and a pre-'75 914). I'm actually considering getting rid of my 944 simply because it's not smog exempt and I'm sick of dealing with the B.S. and extra cost of getting it checked every year, but I also don't want to give the state the satisfaction of making me get rid of the car, which is what they want (I get an "offer" to buy the car every year from them for like $300 or something ).

Anyway, I think high CO can be indicative of a rich condition or too cool running or bad cats and high HC is almost always a rich condition. I think - there's some info around elsewhere on this board about it.

In any case I know you probably don't want to do this on a mag. case, but it'd probably benefit you to run it really hot before the check. And hook up the smog pump. That'll lean it out some.

[stlrj]

You could always get out the 3mm allen and back off the mixture so when you give your tailpipe a quick sniff, you won't pass out.

[knunn911]

I will recalibrate the O2 sensor and adjusted the mixture to a leaner mixture. So to many CO indicate to rich.

[hifeverz]

SMOG Failure in California

I have a 1979 911SC (265k miles on car and 160k miles on the 3.0 liter engine) that failed smog about a month ago. I had changed out NEW the spark plugs, ignition wires, rotor, cap, air filter, smog pump air filter. I had the valves adjusted, reset timing and put in a good used smog pump . . . AND I FAILED !! . . . too rich was the results. I was thinking it may need a new cat, since it was 1979 vintage original!!?? The tech indicated to me that everything seemed fine and that he thought that my smog pump was NOT pumping enough air to dilute the exhaust gases. I therefore had a rebuilt pump already at hand to install. I got retested and it passed with flying colors.
Whew . . . good for another 2 years! . . . and imagine I have one broken head stud that I still should fix . . . !!

Good luck,
Hz
28sep08

[knunn911]

My 1976 911S is a non cat. Two year ago I just passed, after the smog I disconnect the smog pump and store it in the shelve. I have not been driving the car, Maybe 2500 mile over the pass two years. So I don't know what has changed. I will check out the smog pump. Do you know how much flow I should get out of the smog pump? CFM or Ft/Min at what RPM? Or is the car just setting to lone?

Ken

[dvkk]

Originally Posted by hifeverz

SMOG Failure in California

....he thought that my smog pump was NOT pumping enough air to dilute the exhaust gases.

It's called an Air pump. It doesn't pump smog. It's purpose is NOT to dilute the exhaust. It is there to put oxygen into the exhaust so that any excess unburned fuel can have oxygen to finish the combustion process.

And hook up the smog pump. That'll lean it out some.

The air pump has no effect on the A/F ratio. The A/F ratio is determined upstream of the exhaust.

[dvkk]

Originally Posted by knunn911

I when and had the P-car smog and it fail the CO(%) at 15 mph was 3.97 (max is 1.41) and at 25 mph 2.56 (max is 1.21).

You need to post ALL of the numbers, including the limits AND the ones you passed.

[knunn911]

So what the the flow rate of an air pump for a my car?

[knunn911]

The top number is the latest my fail and the bottom is two years ago.

[dvkk]

First, retard your timing by 3º.

Notice how much lower your NOx is this time compared to last time? This indicates your engine wasn't warmed up as much as it was.

Your previous test shows it was running rich even though it passed. A small adjustment may be warranted.

[DRACO A5OG]

Hey, at first I thought you called him a RETARD, LOL.

I agree with warming her up enough prior to testing.

[stlrj]

You might have better luck setting it the way it was two years ago when it passed, before you got the LM-1/ aux box and played with the mixture.

[knunn911]

Once I dial the in the mixture and record the data I will be able to setup the car in two years.

[knunn911]

I passed!! After leaning how the used the LM-1, I was able the set the mixture so I will pass the smog test. I used AFR to %CO chart the set the mixture. Here is a link to the chart http://www.perfectpower.com/Technical_info/afr.asp

So I am back on the road legally.

[juanbenae]

did you ask what the implications of a fail with the "gross polluter" tag? not to chicken litte you but i had a GP commuter car some years ago that because of that test i had to have the car smogged every year after that. i even got it passed after the original GP test but the state still dogged me. would be interested in hearing what you find, or worse discover when you open your registration next year.

i watch close because i do the ssi back to stock exhaust every two years now. i cringe every odd numbered spring year having to replumb the thing. the ssi's are worth every minute of it though.