Oxygen Sensor on 49-states aircooled Vanagon?

Carbs & F.I.

Moderators: Sluggo, Amskeptic

Post Reply
User avatar
SlowLane
IAC Addict!
Location: Livermore, CA
Status: Offline

Oxygen Sensor on 49-states aircooled Vanagon?

Post by SlowLane » Wed Aug 03, 2011 9:20 pm

The background: I'm getting together the bits and bobs that I believe I need to get my Canadian-spec '81 Westy smogged here in Calfornia.

With the exception of not having a cat, the Canadian FI system was the same as the 49-states model (according to Bentley). So I figured that, in addition to doing all the usual vacuum leak sealing and tuning stuff, I'd need to get the EGR system operational and install a cat, then tune the AFM as per Colin's procedure.

I then enlisted the aid of the local VW guru, who is very well regarded for his expertise in Vanagon engine conversions. After consdering the problem for awhile, he came back with the opinion that I also needed to install an oxygen sensor and a matching ECU. He asserts that Federal-spec air-cooled Vanagons had oxygen sensors and tha tthe smog referee will expect there to be one.

I was dumbfounded. Bentley only shows an O2 sensor for the California-spec models of that era, and all I've read here and on the Samba suggests the same. I really don't know what ECU he's planning on using, as the California one would also require a Cali wiring harness, AFM, distributor, coil(?).

So I need either more confirmation of my belief that I don't need an O2 sensor, or if I do, what Federal-spec ECU should I be sourcing to interface to the O2 sensor?

Vanagon ECU numbers and version are pretty confusing. My ECU is a 039-906-021B, which according to some sources is correct for manual transmission Federal Vanagons and the '79 bus. Other sources say that the correct ECU is 039-906-021E (which some other sources say is the ECU for '79 California Auto transmission...)

Can anyone with an '81 -'83 aircooled 49-states Vanagon tell me whether their vans have (or originally had) an O2 sensor? And if they did, what model ECU it's used with?

Thanks so much,
Lyle
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Oxygen Sensor on 49-states aircooled Vanagon?

Post by Amskeptic » Wed Aug 03, 2011 10:03 pm

SlowLane wrote:The background: I'm getting together the bits and bobs that I believe I need to get my Canadian-spec '81 Westy smogged here in Calfornia.

With the exception of not having a cat, the Canadian FI system was the same as the 49-states model (according to Bentley). So I figured that, in addition to doing all the usual vacuum leak sealing and tuning stuff, I'd need to get the EGR system operational and install a cat, then tune the AFM as per Colin's procedure.

I then enlisted the aid of the local VW guru, who is very well regarded for his expertise in Vanagon engine conversions. After consdering the problem for awhile, he came back with the opinion that I also needed to install an oxygen sensor and a matching ECU. He asserts that Federal-spec air-cooled Vanagons had oxygen sensors and tha tthe smog referee will expect there to be one.

I was dumbfounded. Bentley only shows an O2 sensor for the California-spec models of that era, and all I've read here and on the Samba suggests the same. I really don't know what ECU he's planning on using, as the California one would also require a Cali wiring harness, AFM, distributor, coil(?).

So I need either more confirmation of my belief that I don't need an O2 sensor, or if I do, what Federal-spec ECU should I be sourcing to interface to the O2 sensor?

Vanagon ECU numbers and version are pretty confusing. My ECU is a 039-906-021B, which according to some sources is correct for manual transmission Federal Vanagons and the '79 bus. Other sources say that the correct ECU is 039-906-021E (which some other sources say is the ECU for '79 California Auto transmission...)

Can anyone with an '81 -'83 aircooled 49-states Vanagon tell me whether their vans have (or originally had) an O2 sensor? And if they did, what model ECU it's used with?

Thanks so much,
Lyle
If anyone has a Federal 1981 Vanagon, look at the decal on the door post or the emissions decal if you still have one that I believe was on the license plate door(?). "non-catalyst" had to be spelled out.
Also, Lyle, if theSamba has the Vanagon owners manuals posted, check it out.
As I recall, there was the three-way catalyst in the California models that had to have an oxygen sensor. There were Federal catalyst models that did not require the "Lambda Loop".
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

User avatar
SlowLane
IAC Addict!
Location: Livermore, CA
Status: Offline

Re: Oxygen Sensor on 49-states aircooled Vanagon?

Post by SlowLane » Wed Aug 03, 2011 11:09 pm

Amskeptic wrote: As I recall, there was the three-way catalyst in the California models that had to have an oxygen sensor. There were Federal catalyst models that did not require the "Lambda Loop".
Colin
Thank you for the quick feedback, Colin. Your last comment twigged a thought here: with the recent California requirement that all catalytic converters sold here be CARB-approved, it seems likely that the only cat I can get for it now is a three-way type, which would then require that I have a feedback loop (well, if I wanted the cat to last more than a week, at any rate). That might be what the master mechanic was getting at. Hmm.

I'm starting to suspect that I may be looking at converting the whole system to California-spec. :pale: And just after I managed to source a Federal EGR filter, too.

Hey, it's an adventure... I'll check on TheSamba for the owners manuals.
Lyle
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

User avatar
Gypsie
rusty aircooled mekanich
Location: Treadin' Lightly under the Clear Blue!
Status: Offline

Re: Oxygen Sensor on 49-states aircooled Vanagon?

Post by Gypsie » Thu Aug 04, 2011 9:08 am

My understanding is the 49 states models in that era did not have O2 sensors.

When you do your AFM ala Colin method, leave it in a "I want more fuel" condition as the Colin method puts it in the rich zone. Do you have access to an LM1?

Help me understand. To be registered in Cali you are being required to install a threeway cat? Are you not permitted to purchase (online say) a standard Cat for the rig and get it back to it's designed emissions standards rather than the 'new and improved' emissions standards?

Also, I don't believe that they will open anything up so, the EGR system could be intact an not functional (as many are by now).
So it all started when I wanted to get better gas mileage....

User avatar
airkooledchris
IAC Addict!
Location: Eureka, California
Contact:
Status: Offline

Re: Oxygen Sensor on 49-states aircooled Vanagon?

Post by airkooledchris » Thu Aug 04, 2011 9:26 am

To register your Vanagon in California it has to have all of the smog equipment that it left the factory with. Nobody expects you to be running more or non-original equipment in order for you to pass.

The first thing id do is take your Vanagon to a smog testing place and check to see what THEY expect. There's no point in throwing money at something before verifying it's real world requirement.


I have registered a 1981 aircooled Vanagon here in California. It was a Federal model that had never been registered in California before, not a California model.

As such, I was required to have all of the stock equipment installed and working properly.
This meant I needed a CAT (they didn't check to see if it was "CARB" approved, only visually confirmed it was just there. The thing with CARB approved cats is that you can't sell one to someone in CA that ISN'T approved - they can't provide that you haven't had this CAT on your Vanagon all along regardless of what it says on the side.)

I also needed to show that my EGR was connected, and they DID test to be sure it was working. With the Vanagon running, he disconnected the little line that connects it to the throttle, so you could manually activate the valve and then feel that the EGR pipe started to get warm as it allowed the exhaust gasses into the mixture.

In the end, as long as you can pass the actual snif tester, your EGR is connected AND working, and there is something that looks like a CAT installed inline in your exhaust system - you'll pass.

But I would still go to a smog station and find out for SURE what they expect you to have before spending any money on tracking these parts down and having them installed. Certainly don't get tricked into thinking you need to convert this to a CA system and have to go find a new ECU, AFM, O2 sensor, and wiring harness.
1979 California Transporter

User avatar
Gypsie
rusty aircooled mekanich
Location: Treadin' Lightly under the Clear Blue!
Status: Offline

Re: Oxygen Sensor on 49-states aircooled Vanagon?

Post by Gypsie » Thu Aug 04, 2011 10:09 am

So perhaps, the cat would not be required? Check for that sticker!

If you have to install a cat (or want to for your footprint's sake...) you might consider going to 49 state's standard
airkooledchris wrote:The thing with CARB approved cats is that you can't sell one to someone in CA that ISN'T approved - they can't provide that you haven't had this CAT on your Vanagon all along regardless of what it says on the side.
Wow, even the online sources are restricted from this sale? P'raps someone could purchase it and send it to you 'as a gift'...

Doesn't surprise me (much) that they confirm EGR functionality.

EGR shouldn't be too hard to get in working order if'n you have all the parts. If it's clogged you may be able to open it up with a length of 1/4' drain snake on power drill. I'll give more detail if this is of interest.

Just work on getting it to stock condition. If you are using 'a local VW guru' because you haven't been elbow deep in it much, it's time to roll up your sleeves.
So it all started when I wanted to get better gas mileage....

User avatar
SlowLane
IAC Addict!
Location: Livermore, CA
Status: Offline

Re: Oxygen Sensor on 49-states aircooled Vanagon?

Post by SlowLane » Thu Aug 04, 2011 9:12 pm

Chris and Gypsie: thanks for your thoughtful feedback. Your suggestions more or less mirror what my original intentions were. I have enough spare EGR bits to put together a working system (the final serendipitous piece was an unrusted, gently used Federal EGR filter from a kind fellow in Oregon who I contacted on The Samba).

I'm actually looking forward to having a working EGR system so I can see how much it lowers CHT, and if it balances out the temperatures between cylinders. Currently, #3 cylinder runs between 20 and 30 degrees hotter than the other cylinders. Looking in the air plenum, I note that #3 has roughly triple the number of holes assigned to it in the EGR distribution pipe, so it must get more than its fair share of the exhaust gas. I'm betting that should translate to better temperature balance between the cylinders.

But I digress. The question of whether to use a cat or not is tricky. As I said, Canadian models didn't have them (Bentley is clear on this, though I don't have any "non-catalyst" stickers anywhere that I can see), and if the Federal models didn't have oxygen sensors, then the cats they run must be the older oxidation type. I'm not certain I can argue to the smog referee that I can't use a CARB-approved cat, and if I show up with a new shiny, non-CARB approved cat, I might have some 'splain'in to do. Maybe some helpful IAC member would be willing to sell me an older, not-shiny, yet still functional oxidation cat? Chris, what's your plan when your current cat gives up the ghost?

Your suggestion to take it to the smog guys before getting too deep is well-received, Chris. I intend to do that once I have the EGR system working.

As far as rolling up my sleeves goes, I'm way beyond elbow deep with aircooled VWs. I've been wrenching on them since about 1979. My chief reason for keeping this van and taking the trouble to move it down here is the amount of personal sweat equity I invested in rebuilding the engine back in 2005. That journey took me the better part of a year, and took up the better part of my kitchen for the duration (ah, to be single again...).

Main reason I consulted the local VW guru (and he really is a master at Vanagon engine conversions) is that I don't have access to welding equipment, and at the time I thought I was going to have to adapt a Cal-spec or Beetle EGR filter to the Federal EGR plumbing. I totally didn't expect him to come back with the oxygen sensor gambit. He was adamant that Federal Vanagons from late 1980 onwards had O2 sensors. And I'm slighly confused by Bentley, because even though they identify the O2 sensor as California-only on the system diagram in section 24, the electrical diagram on p. 97.19 for '82 and '83 AFC systems doesn't flag it as California-only. Which make me wonder if Federal Vanagons got the O2 sensor in '82. But if they did, they would require a different ECU, and from what I've been able to determine, the same ECU works for all Federal manual transmission vehicles from '79 through '83. Any idea what the difference is between a 039-906-021B and a 039-906-021E ECU?

I don't have an LM-1, though I have been looking at getting an LC-1, which I presume is the successor to the LM-1. Anyone had experience with the newer model?

Sorry for the long-windedness. It's just that I don't get much of a chance to talk about this stuff with anyone else. Thanks for your time and suggestions.

Lyle
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

User avatar
SlowLane
IAC Addict!
Location: Livermore, CA
Status: Offline

Re: Irvine Interlude

Post by SlowLane » Sat Jun 28, 2014 1:17 pm

Lanval wrote: The LM-1 is a great device, but it's hard to tell, when placed in the pipe end, if you're seeing real numbers, or just what's left after the catalytic converter has done it's job. In any event, we couldn't tell for sure if the enrichment was working; didn't feel that way according to the butt dyno, and the LM-1 had no good info to appease our anxious souls.

If I may offer a modest suggestion to aid in soothing your furrowed brows.

With an Innovate Motorsports LC-1 (or its successor, the LC-2), you can install a modern wide-band oxygen sensor in place of your stock narrow-band sensor. The LC-(1|2) has two programmable analog outputs: the default configuration of one output is a linear 0-5 VDC signal appropriate for feeding onto an AFR gauge or a datalogging device. The other output is configured to act like a traditional narrow-band sensor, even down to deferring any useful output for a period of time after startup to simulate the warmup period of an unheated narrow-band sensor. So you could re-wire your FI system to use the second LC-1 output. Done correctly, you could easily swap back to the stock narrow-band sensor for smog inspections if necessary.

By placing the wide-band sensor in the stock location ahead of the cat, you should get a much more reasonable indication of what your mixture is doing. You can even tell if your full-throttle enrichment switch is working. I can sure tell with my van. When I mash the pedal to the floor, the gauge literally jumps from whatever reading it's at to about 10.0:1. Now, that's on my primitive '81 system. On your more modern system there may be extra gizmos (like the oddly-named OXS relay) which prevent full-throttle enrichment below 3000 RPM (it basically sits in series with the WOT switch and only completes the circuit at revs above 3000).

The LC-1 + wide-band sensor lists for $199 at Innovate's website. The LC-2 + sensor lists for $189. That's with no gauge. But if you google around you can find LC-1, sensor and gauge packages in the $160 region. There are digital and analog gauges available. My preference is for the analog gauge, because you can actually see what the effect is of various conditions as you drive around, without having to mentally interpret the digital readout
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

Post Reply