DEQ nazis VS. '76 911S/3.0 CIS non cat

[gungadin]

What is the current wisdom on how to cheat the DEQ?
I drove thru the DEQ last weekend and flunked the CO by a very slim margin.
What can I do myself to sneak thru?
I guess there's a 3mm allen screw up on the CIS to adjust mixture but I hesitate.
Is it clockwise for richer and CCW for leaner?
Can someone give me a feel for how much to turn it so that it will affect the emissions without screwing anything up? (And I've been warned I can get into trouble here).
Should I re-adjust my timing at all?
Any and all suggestions are very much appreciated.

BTW Portland peeps with this problem. The "special interest" plates exempt you from ever having to renew your registration again. BUT you'll have to pass DEQ once before they will issue to you. At least that is what the guy at the DMV counter told me. Also it's not for your daily driver cars (me). Only occasional events. You can keep your plates if they are the origionals or you can get the "SP" plate for the back (no front plate).

[HarryD]

It is not necessary to"cheat". High CO means incomplete combustion.

Before testing you should drive you car hard for 20-30 minutes at high revs to get the engine hot and burn out any carbon. Be sure your plugs, wires, rotor and cap are in top notch shape.

How did the NOx and HC look?

Here are the charts that show how mixtures ratio affect emissions:



From this you can see that if you are at spec (i,e, at 1.0 lamda) leaning the mixture will reduce CO while raising HC and NOx.

The best way to do this is to bring it to a shop and have them put it on the machine and test all three gases and adjust your mixture until it is ok. They can do this in less than 30 minutes.

FWIW, you DO NOT want to guess at the setting and have DEQ test for you. If you see them too often, they will become very interested in you, but not in a positive way.

[HarryD]

Originally Posted by HarryD

It is not necessary to"cheat". High CO means incomplete combustion.

Before testing you should drive you car hard for 20-30 minutes at high revs to get the engine hot and burn out any carbon. Be sure your plugs, wires, rotor and cap are in top notch shape.

Check the simple things first before messing with the mixture.

BTW... Interesting story... My old '93 Taurus would not pass DEQ at 180,000 miles due to high HCs. I decided to see what the problem might be. When I pulled the distributor cap of the car, the insides were green, my wire ends were green and there was almost no metal in the rotor. I replaced these parts (they had not been replaced in 6 years (over 100,000 miles) and the car passed easily. The car ran better after as well.....

[gungadin]

Your graphs look like they are about before and after a cat.
I don't have a cat. Or smog pump for that matter.

I don't see anything about NOx on the report at all.
The HC were 88 idle and 99 at RPM (?the standard being 300?)
The CO was 2.6292 at idle and 2.738 at RPM (std is 2.5 allowable.)
The CO2 was 13 at idle and 12.9 at RPM.
anyway I think I'm reading this right.

BTW I happened to go to the SUNSET DEQ that day and it looked like IKEA at Christmas so I drove over the hill to the Scappoose DEQ. I was the only car there.
The printed out report didn't have any graphs on it (like I've seen before) so I couldn't tell if the exceeded amounts were just a short spike or for the duration of the test period or what.

The guy invited me to drive around and come back to retest but like you say,,, I don't want to wear out my welcome. Not that I didn't think about it tho. I actually did drive around the neighborhood in 1st gear @4K RPM for a while but it was cold and raining and I couldn't really get the oil temp up above 180 so I bailed.
This Saturday promises to be much warmer and dry too!!!

[HarryD]

If you get it leaned out a bit, you should get it to pass. Like I said, go to a Porsche shop and have them do it on the machine. shouldn't cost much or take much time.

[RWebb]

THE Nazis murdered millions.

You might think about that before tossing the word around.

You are also asking people to help you break the law. There is a reason for the law - people can't breathe the air without damaging their health.

[gungadin]

My apology for offending anyone with the careless use of the word Nazi.
Being somewhat of a historian, I'm quite aware of their atrocities. I do not make light of that.
I do however, see the word "tossed" on this forum approximately 300 times by my quick search. Mostly by people from CA and OR who are required to meet emissions.
So Randy can you show me a posting where you chastised someone else for this unfortunate reference? I'll be embarrassed if you can.

And Randy? No. I didn't, don't, and won't ask anyone to help me break the law.
I know why the law exists too. I'm a DIY kind of guy and completely capable of breaking the law without any direct help. There as well, lots of spirited discussion on this forum.

Pollution is certainly a problem and I wish our cars didn't pollute. But for a small vehicle they definitely have a big carbon footprint. What with only 22mpg and 14 qts. of oil between changes. Three of which are tolerated to just disappear into the atmosphere or onto the earth before we break out another case. Now I hope you aren't throwing those plastic (made from oil) bottles into the trash!

AND, I hope those gentle and hard working American DEQ folks don't catch wind of that last little "allowable oil consumption" fact or there will be plenty of us breaking the law all by ourselves just starting the iconic little heaps up.

People will rise up and scream...."GET THAT CUTE LITTLE CAR OFF MY PLANET!!"
Try to imagine a flat bed stacked high with old crushed 911's because they are illegal to drive and the DEQ makes us pay a fee to crush and recycle them because they are bad for us.

[Paulporsche]

I'm not sure what would constitute breaking the law, but I would think that setting your CO to the right figure would be a GOOD thing.

Obviously you can have a shop set it, but since you are a DIY guy you can turn that screw CCW to lean it. Since you are so close, you will probably need only one 1/16th turn CCW to get it down at the most, since 1 complete turn is between 8 and 12%.

You may find it only takes a slight bump or nudge to get it down all you need.

[RWebb]

I probably have - not that it matters. Others have too - feel free to search here and OT if you are so inclined.

2nd - it is not the CO2 emissions that are regulated; it is NOx; HC, and CO

and BTW, I recycle my oil - Eugene makes it easy (curbside) - surprised PDX doesn't

[Porsche-O-Phile]

Throw a can of Seafoam through the engine (in a well-ventilated area. . . you'll see why ). Then as suggested, heat it up, give it a good Italian tune-up. Then try. Bet you pass.

[gungadin]

Thanks Paul. This is exactly what I wanted to know.

Originally Posted by Paulporsche

I'm not sure what would constitute breaking the law, but I would think that setting your CO to the right figure would be a GOOD thing.

Obviously you can have a shop set it, but since you are a DIY guy you can turn that screw CCW to lean it. Since you are so close, you will probably need only one 1/16th turn CCW to get it down at the most, since 1 complete turn is between 8 and 12%.

You may find it only takes a slight bump or nudge to get it down all you need.

[HarryD]

Originally Posted by RWebb

I probably have - not that it matters. Others have too - feel free to search here and OT if you are so inclined.

2nd - it is not the CO2 emissions that are regulated; it is NOx; HC, and CO

and BTW, I recycle my oil - Eugene makes it easy (curbside) - surprised PDX doesn't

Randy,

FYI

We at Portland have curbside oil recycling also.

Also, tuning your car to pass DEQ will typically also tune it properly for normal use. In his case, it is a non-cat car so it has always needed to be tuned properly.

And while I applaud those who DIY, he should think twice about setting the mixture his self. Having a shop set the mixture is relatively cheap and avoids the risk of going too lean and burning a hole in your cylinder or piston top.

[HarryD]

Originally Posted by gungadin

Your graphs look like they are about before and after a cat.

You are correct. The only curves you care about are the dotted "a" ones. Whether you have a cat or not, your best operating point is at stoichiometric.

As you can see HC, NOx and CO are interrelated.

[Joe Bob]

Put a gas analyzer on it and adjust it....

[Steve@Rennsport]

Originally Posted by HarryD

....And while I applaud those who DIY, he should think twice about setting the mixture his self. Having a shop set the mixture is relatively cheap and avoids the risk of going too lean and burning a hole in your cylinder or piston top.

Bravo!

That mixture screw in the airflow meter is quite sensitive as Paul suggested and its very easy to make the engine (unintentionally) dangerously lean. Assuming that a 1/16th of a turn CCW does the trick just to pass DEQ, one really needs either a 4-gas, 5-gas or an accurate AFR meter to set the CO for the engine's long-term health.

I've seen far too many examples of such "Kentucky Windage Tuning" and its consequences and I'd stand by my private advice to Del to do this properly,..

[gungadin]

Damn. I knew it was only a matter of time before Steve busted me.

[Steve@Rennsport]

Originally Posted by gungadin

Damn. I knew it was only a matter of time before Steve busted me.

Sorry pal,.....I'm just watching your Six,........

[gungadin]

And Thank You for that Steve.
You're a Prince.

[Porsche-O-Phile]

What do you think of the LM1 (available here on Pelican and elsewhere) for tuning at home? Is it reliable enough?

[gungadin]

Thanks and credit to all whose suggestions have helped make it legal for the little car to live and breathe in the big city.
Also:
Fresh cap/rotor
new magnacors
Checked plugs (all a bit darker than one would like to see)
1/16 CCW tweak to the mixture screw. (later returned 1/32 CW).
The "Italian tune-up".
$21 to the DEQ.