Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
84 vanagon emission test failed : high NOx
Forum Index -> Vanagon Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
Author Message
bavareze
Samba Member


Joined: January 03, 2010
Posts: 81
Location: los angeles, ca
bavareze is offline 

PostPosted: Wed Dec 09, 2015 11:17 pm    Post subject: 84 vanagon emission test failed : high NOx Reply with quote

Hi guys

my 84 fuel inj watercooled westy failed emissions due to high nox.

i see no obvious signs of vacuum leaks

all wiring in place, everything looks normal

what is the first candidate for this? catalytic?

thanks for the help!

cheers!
_________________
- www.b66ama.com - 29.000 miles in South America -
Back to top
View user's profile Send private message Visit poster's website Gallery Classifieds Feedback
Type17
Samba Member


Joined: April 24, 2012
Posts: 300
Location: Chicagoland
Type17 is offline 

PostPosted: Wed Dec 09, 2015 11:29 pm    Post subject: Re: 84 vanagon emission test failed : hight NOx Reply with quote

Depends, what did the other readings look like? How old is the cat?

See if you can get a shop to test at the pre-cat port to see if the cat is doing anything before replacing it.
Back to top
View user's profile Send private message Facebook Gallery Classifieds Feedback
bavareze
Samba Member


Joined: January 03, 2010
Posts: 81
Location: los angeles, ca
bavareze is offline 

PostPosted: Wed Dec 09, 2015 11:46 pm    Post subject: Re: 84 vanagon emission test failed : hight NOx Reply with quote

i can have them do that. where is that port located at?
_________________
- www.b66ama.com - 29.000 miles in South America -
Back to top
View user's profile Send private message Visit poster's website Gallery Classifieds Feedback
Howesight
Samba Member


Joined: July 02, 2008
Posts: 3260
Location: Vancouver, B.C.
Howesight is offline 

PostPosted: Thu Dec 10, 2015 3:13 pm    Post subject: Re: 84 vanagon emission test failed : hight NOx Reply with quote

High NOx on a 1.9 WBX can be due to several causes, but they all involve overly-high in-cylinder combustion temperatures. I am going to assume that the excess of NOx was not merely marginal and a one-off occasion.

Since the oxygen sensor is a consumable maintenance item, start by replacing it. Then test again. If you still do not pass, but are very close to the line, you can delay replacing your catalytic converter (over $300 for the California version) by trying a couple tricks.

1. Assuming that your HC emissions were significantly below a fail, then try to ensure the vehicle and the engine are just at operating temperature and not any hotter. This is tricky to do. You might have to park near the testing facility to let the van cool down and then proceed.

2. A related trick is to use a slightly colder thermostat. If you go too cold, you will fail on HC's.

3. A very effective technique you can try is to retard your spark timing by about 5 degrees. This reduces in-cylinder temperatures, but also reduces power and gas mileage, so re-set the timing after your emissions test.

4. You can add a temporary water injection system that sprays a very small amount of water into the intake manifold. You have to be really strongly against a new cat for this to be a viable solution. This is really for the Wile E. Coyote in all of us.

5. If none of the above allow a pass, then buy a new catalytic converter. That'll fixya.
_________________
'86 Syncro Westy SVX
Back to top
View user's profile Send private message Gallery Classifieds Feedback
AtlasShrugged
Samba Member


Joined: October 30, 2008
Posts: 1605
Location: Decatur, Ga. USA
AtlasShrugged is offline 

PostPosted: Thu Dec 10, 2015 7:20 pm    Post subject: Re: 84 vanagon emission test failed : hight NOx Reply with quote

One problem our old WBX engines have is the standards they were required to meet back in the day were more generous.

When my Vanagon missed the NOX number..it was always very slight.

So the question is. how far off was your NOX numbers?

If yours were close but no cigar..and the engine is tuned correctly..then a new Cat may be the only solution.

Thankfully in Georgia they stop requiring emission testing after 25 years..
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
bavareze
Samba Member


Joined: January 03, 2010
Posts: 81
Location: los angeles, ca
bavareze is offline 

PostPosted: Fri Dec 11, 2015 12:35 pm    Post subject: Re: 84 vanagon emission test failed : hight NOx Reply with quote

hey, I'm going to adjust a few things, i ordered new fuel lines etc and i will go again to the smog station. the last test was some time ago and i forgot.

thanks all for the help

regarding the timing retarding 5deg: is this supposed to be done by moving 5 deg left or right?
_________________
- www.b66ama.com - 29.000 miles in South America -
Back to top
View user's profile Send private message Visit poster's website Gallery Classifieds Feedback
SyncroChrick
Samba Member


Joined: January 10, 2005
Posts: 1010
Location: San Francisco, CA
SyncroChrick is offline 

PostPosted: Sun Dec 13, 2015 6:38 pm    Post subject: Re: 84 vanagon emission test failed : hight NOx Reply with quote

My last van failed on slightly too high NoX and then passed just by tweaking the timing a little bit.

Everything else was in good shape.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
bavareze
Samba Member


Joined: January 03, 2010
Posts: 81
Location: los angeles, ca
bavareze is offline 

PostPosted: Mon Dec 14, 2015 1:09 am    Post subject: Re: 84 vanagon emission test failed : hight NOx Reply with quote

SyncroChrick wrote:
My last van failed on slightly too high NoX and then passed just by tweaking the timing a little bit.

Everything else was in good shape.


turned it to left or to right?
_________________
- www.b66ama.com - 29.000 miles in South America -
Back to top
View user's profile Send private message Visit poster's website Gallery Classifieds Feedback
SyncroChrick
Samba Member


Joined: January 10, 2005
Posts: 1010
Location: San Francisco, CA
SyncroChrick is offline 

PostPosted: Mon Dec 14, 2015 11:26 am    Post subject: Re: 84 vanagon emission test failed : hight NOx Reply with quote

bavareze wrote:
SyncroChrick wrote:
My last van failed on slightly too high NoX and then passed just by tweaking the timing a little bit.

Everything else was in good shape.


turned it to left or to right?


Right I believe but that does not really matter since I don't know where you start from on your van.

I always follow the "3000 rpm" method with a 2" mark - look for it on this forum
Back to top
View user's profile Send private message Gallery Classifieds Feedback
SyncroChrick
Samba Member


Joined: January 10, 2005
Posts: 1010
Location: San Francisco, CA
SyncroChrick is offline 

PostPosted: Mon Dec 14, 2015 11:26 am    Post subject: Re: 84 vanagon emission test failed : hight NOx Reply with quote

bavareze wrote:
SyncroChrick wrote:
My last van failed on slightly too high NoX and then passed just by tweaking the timing a little bit.

Everything else was in good shape.


turned it to left or to right?


Right I believe but that does not really matter since I don't know where you start from on your van.

I always follow the "3000 rpm" method with a 2" mark - look for it on this forum
Back to top
View user's profile Send private message Gallery Classifieds Feedback
bavareze
Samba Member


Joined: January 03, 2010
Posts: 81
Location: los angeles, ca
bavareze is offline 

PostPosted: Wed Jan 06, 2016 7:36 pm    Post subject: Re: 84 vanagon emission test failed : high NOx Reply with quote

hi!

after trying all tricks I came to conclusion I had to replace the catalytic converter and that's what I did and the van passed the test. Now this is the result and I am wondering whether, apart from being passable, it is actually properly tuned... I am worried that the new cat might get ruined again if something is wrong.

Thanks again for all the help!

Image may have been reduced in size. Click image to view fullscreen.

_________________
- www.b66ama.com - 29.000 miles in South America -
Back to top
View user's profile Send private message Visit poster's website Gallery Classifieds Feedback
AtlasShrugged
Samba Member


Joined: October 30, 2008
Posts: 1605
Location: Decatur, Ga. USA
AtlasShrugged is offline 

PostPosted: Thu Jan 07, 2016 5:40 am    Post subject: Re: 84 vanagon emission test failed : high NOx Reply with quote

To check your actual tail-pipe numbers..there is a port ahead of the Cat..and the fuel mixture is checked there with a CO machine. Not a DIY as it requires the test equipment. I don't think that is your problem.

The problem is the tail pipe emission numbers are more strict now. Twenty years ago they were easier to do with a WBX.

With your new Cat..the NOX numbers are borderline now in the 15mph range...in a couple of years your NOX numbers will be higher as the Cat's NOX efficacy declines with use. And..the standards may become even more strict requiring an even lower NOX number than this year.

Some other Vanagon owners would suggest removing your new Cat and installing your old one..and reinstall the new Cat next time you have an emissions test.
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Vanagon All times are Mountain Standard Time/Pacific Daylight Savings Time
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2023, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB
Links to eBay or other vendor sites may be affiliate links where the site receives compensation.