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passing emmisions

 
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MikeDanger  



Joined: 21 Nov 2002
Posts: 538
Location: Denver

PostPosted: Thu Sep 10, 2020 4:56 pm    Post subject: passing emmisions Reply with quote

Well, I need to park my 81 931 outside and I need plates on it, so I have to take it to get emissions, and it failed
For 81 and earlier, they just do the tail pipe idle test

It always seemed a little rich at idle, I have adjusted the CIS mixture, seems to make little difference, I leaned it to where it was barely running. replaced most of the vacuum lines, some of the rubber elbows, the hose running to the bottom of the CIS meter, replaced the o2 sensor the night before.
Also I tried different WUR (have 2 Spares) no noticeable difference.

It has the original Cat(and actually the exhaust is cracked right at the weld on the turbo outlet flange)

I get a slight bit if smoke, not noticeable out side but in the garage you can see it, don't see anything behind the car when driving.

OH, also I ran about 40% e85 in the tank

I just need it to pass the idle test to get plates!

tried to attach the test results:




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morghen  



Joined: 21 Jan 2005
Posts: 8274
Location: Romania

PostPosted: Thu Sep 10, 2020 5:09 pm    Post subject: Reply with quote

You can get a new CAT and it should make a big difference..but mine always passed emissions.
Set the timing properly and the mixture and you should be ok...but an uncracked exhaust is a must for passing emissions.
Also...your idle should be 950 not 1350
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MikeDanger  



Joined: 21 Nov 2002
Posts: 538
Location: Denver

PostPosted: Thu Sep 10, 2020 6:07 pm    Post subject: Reply with quote

This is an s2 so I can't really set the timing AFAIK?

that idle speed is made up, they don't actually mess with the car at all, as is the second speed "2500", the computer just estimates, they don't even touch the car, just stick a probe in the tail pipe, for 2-3 minutes.
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morghen  



Joined: 21 Jan 2005
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Location: Romania

PostPosted: Thu Sep 10, 2020 6:28 pm    Post subject: Reply with quote

boh...then just fix your exhaust and set your idle to 950...tune the mixture right on their rig to meet the emissions.
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MikeDanger  



Joined: 21 Nov 2002
Posts: 538
Location: Denver

PostPosted: Fri Sep 11, 2020 4:07 pm    Post subject: Reply with quote

morghen wrote:
boh...then just fix your exhaust and set your idle to 950...tune the mixture right on their rig to meet the emissions.


I doubt the exhaust crack would hurt, as it would probably show less HC's with the crack, since some of them are escaping.

But You can't do live tuning, its a state facility, they don't show live data, I tried. it just does the timed test and gives a print out.
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MikeDanger  



Joined: 21 Nov 2002
Posts: 538
Location: Denver

PostPosted: Sat Sep 12, 2020 11:40 am    Post subject: Reply with quote

I was reading on the 911 thread here : http://forums.pelicanparts.com/porsche-911-technical-forum/218814-made-adjustable-wur-step-step-got-pics.html#post1900313

about the WUR, and how even if the CIS meter is leaned, the WUR could still make it run rich, and the WUR might need to be adjusted?
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morghen  



Joined: 21 Jan 2005
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Location: Romania

PostPosted: Sat Sep 12, 2020 5:14 pm    Post subject: Reply with quote

Yeah, you can get your wur rebuilt and made adjustable...but rebuilt should be enough. Cracked exhaust ca affect the readings in a significant way.
Sustem expects a certain amount of gases at a certain amount of rpms.
So make sure the idle is right, the exhaust isnt blowing out and you have proper mixture.
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MikeDanger  



Joined: 21 Nov 2002
Posts: 538
Location: Denver

PostPosted: Sat Nov 07, 2020 8:10 am    Post subject: Reply with quote

I passed! not sure exactly what did it but... I made the WUR adjustable, and leaned it out, then I leaned out the CIS meter. and finally I drained all the gas, put one gallon in... drove to the testing place, then put in a gallon of alcohol.
the numbers were half what they were before.
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