So let me see if  I understand. My Cat could be spent, but likely due to
an abnormal HC level going into it that speeded the process ?

Does the fact that the HC numbers at 2500rpm are not high at all still
point to a burned out cat? I don't understand this.

Meaning if the cat is not working well, why wouldn't I see high HC
levels at 2500rpm too?

So I might be best to:

check and adjust timing as you indicate
adjust idle
replace cat
replace and or check/clean plugs
check some of the other basic ignition items folks have mentioned
anything else  ??
smog retest

Thanks again for the good info...

-john

Dennis Haynes wrote:
> Yes!
> All aftermarket cats including the Emicco do not work as well or last as
> long normally as OEM. They do not have the volume, and surface area of
> active material. That said, Cats do not die, they are murdered. At 400 PPM
> HC going in even an OEM one did not stand much of a chance at long life.
>
> Your compression readings are low but there could be many causes. I have
> learned not to make conclusions on compression tests alone unless
> something is broken. You also need to do a leak down do determine of you
> have a ring or valve issue. I think proper setting will get it somewhat
> cleaned up for you.
>
> Here in NY we get smogged every year and the limits for our vans is 120
> ppm HC and 1.2% CO.
>
> Dennis
>
> -----Original Message-----
> From: John Goubeaux [mailto:john@ucsb.edu]
> Sent: Thursday, February 07, 2008 10:12 PM
> To: Dennis Haynes
> Cc: vanagon@GERRY.VANAGON.COM
> Subject: Re: SMOG TEST failure
>
> Thanks Dennis,
>
> I replaced the cat last smog check,   eg 2 yrs ago,   and the O2 sensor
> 18 months ago. Could the cat burn out so soon?
>
> Last time I pulled plugs and replaced and checked compression.(3 months
> ago) I got the following:
> **Note This engine has a lot of miles on it and these values seem low
> but it is still running "OK".
>
> 1)   100
> 2)   100
> 3)   120
> 4)   120
>
> (20 cranks engine cold with a snapon gauge)
>
> -john
>
>
> Dennis Haynes wrote:
>
>> The fact that your CO reading is the same at both idle and 2,500 rpm
>>
> tells
>
>> me the mixture is really good but most likely the cat is shot. However,
>> this appears to be idle only tests so do not worry too much yet. A new
>>
> cat
>
>> will clean it up but it will not last long. You should really be able to
>> get the pre-cat HC at idle well under 150.
>>
>> The high HC at idle has all the tell tale signs of an idle miss. Check
>>
> the
>
>> ignition timing and set as per the Bentley. Follow the procedure of warm
>> engine, disconnect the temp 2 sensor while it is running and then set
>>
> the
>
>> timing. After reconnecting the sensor, set the idle speed slightly high
>>
> to
>
>> 950 or so. This does help. Make sure the oil is not overfilled and also
>> that it is the correct viscosity. A compression/leak down test may be in
>> order here. After confirming compression if you still have the miss and
>> fail inspection again the next step is to check the injectors. Oh, first
>> make sure there are no vacuum leaks. Small ones at the injector seals,
>> manifold boots, etc, can be really bad. If you had an ignition miss fire
>> you would also see the high HC at speed.
>>
>> With a good cat you should really see readings of near "0" for HC and
>>
> CO.
>
>> Dennis
>>
>> -----Original Message-----
>> From: John Goubeaux [mailto:john@ucsb.edu]
>> Sent: Thursday, February 07, 2008 9:28 PM
>> To: Dennis Haynes
>> Cc: vanagon@GERRY.VANAGON.COM
>> Subject: Re: SMOG TEST failure
>>
>> Thanks Dennis,
>>
>> Good summary. Here are all the numbers in order to better diagnose:
>>
>> rpm              %CO2              %O2              HC(ppm)          CO
>> %               RESULTS
>>                      MEAS             MEAS             MEAS
>> MEAS
>> ______________________________________________________________________
>>
>> 915               11.9                  3.2                  424
>>       0.55               GROSS POLLUTER
>>
>> 2571               13.9                 0.5                  66
>>         0.55                  PASS
>>
>>
>> Dennis Haynes wrote:
>>
>>
>>> Emissions issues really are straight forward for those who know how the
>>> system works, what should happen normally, and what causes the various
>>>
>>>
>> gas
>>
>>
>>> failures. Results like you are the justification for emissions test
>>> procedures and with your numbers you are definitely in the league of a
>>> gross polluter.
>>>
>>> For starters, in order for anyone to diagnose you problem, you also
>>>
> need
>
>>> to state the CO amount. For diagnosing, you really want to measure the
>>>
>>>
>> CO
>>
>>
>>> before the catalyst. That is why there is a test port.
>>>
>>> I'll go over the gasses again and if someone wants, feel free to post
>>>
>>>
>> this
>>
>>
>>> on the Wiki.
>>>
>>> Carbon Monoxide is the result of incomplete combustion due to
>>>
>>>
>> insufficient
>>
>>
>>> oxygen being available or combining with the fuel to complete the burn.
>>> Yes, this is the one that is mixture, and temperature related. Why
>>> temperature? The big un-vaporized fuel molecules may not get the oxygen
>>> even if it is available. That is why there are winter fuel blends and
>>>
> we
>
>>> need enrichment to get cold engines started. If the CO is in limits,
>>>
> the
>
>>> fuel injection is basically working. The Vanagon should be able to get
>>> near 1% even before the Cat.
>>>
>>> Excessive Hydrocarbons. This is fuel that never started to burn or get
>>> ignited. Yep, raw gas out the pipe. Usual causes are ignition miss
>>>
> fire,
>
>>> leaking valves, rings, etc. Another phenomenon here is what is known as
>>> the "Lean" miss fire. This is due to slight differences in mixture
>>>
>>>
>> amongst
>>
>>
>>> cylinders with the leaner one failing to "light up". This is that crazy
>>> intermittent miss that can drive you crazy. The Vanagon engne is really
>>> prone to this due to the poorly designed intake system. Over advanced
>>> ignition timing will also add to this as the advance timing will
>>>
> require
>
>>> much less air and fuel to maintain a low idle speed. This results in
>>>
>>>
>> poor
>>
>>
>>> swirl and mixing and the fuel mix will fail to light. If an oil change
>>> fixes this, consider you have a ring or valve-guide problem.
>>>
> Excessively
>
>>> lean or rich mixtures will result in the miss fire.
>>>
>>> Oxides of Nitrogen (NOx). This is the result of excessive flame
>>> temperatures. Engine design, ignition timing, and load all add to
>>>
> create
>
>>> this. The controls are timing settings (why we have the dual diaphragm
>>> distributors before Digifant), low compression, most vehicles EGR, and
>>>
>>>
>> in
>>
>>
>>> everything 81 and later the three way oxidation reduction catalyst with
>>> the O2 sensor for final mixture control. The downside of this is that
>>>
> we
>
>>> can no longer use lean mixtures to improve fuel economy. This is also a
>>> major problem with Diesel engines as they have high compression, and
>>>
>>>
>> lots
>>
>>
>>> of excess air.
>>>
>>> Now give us the rest of the readings and I will try to give you
>>>
>>>
>> diagnoses
>>
>>
>>> and direction. Resist the temptation to tamper with the afm and make
>>>
>>>
>> blind
>>
>>
>>> adjustments or start changing parts.
>>>
>>> Dennis
>>>
>>> -----Original Message-----
>>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
>>>
>>>
>> Of
>>
>>
>>> John Goubeaux
>>> Sent: Thursday, February 07, 2008 5:31 PM
>>> To: vanagon@GERRY.VANAGON.COM
>>> Subject: SMOG TEST failure
>>>
>>> My 90 failed the California smog test today. In short, the idle values
>>> were off with HC ppm at 424 where max allowed is 120  though the
>>>
> 2500rpm
>
>>> values passed fine and are way below limits.
>>>
>>> So I am looking for some clues on where to start with this, and while I
>>> realize it might not be straight fwd, thought I would see if anyone has
>>> some insights. Replacing components one by one might get expensive so i
>>> was hoping on narrowing it down on what it **could be.
>>>
>>> Idle is fine though it has been rough for a while at startup and I have
>>> had intermittent, what appears like missing at high speeds when
>>> accelerating.  I had thought that i was seeing what folks refer to as
>>> the "vanagon syndrome"  but with with the idle values like these am
>>> thinking that it could be as a result of  the idle control valve
>>>
> (though
>
>>> it vibrates), the idle control unit or the coolant temp sensor (which i
>>> am told can cause a rich mixture.
>>>
>>> It looks like Bentley has clear steps to trbl shoot the idle though I
>>>
> am
>
>>> not sure, without the proper tools, if I can make the needed
>>>
> adjustments
>
>>> it calls for.
>>>
>>> Thanks in advance for any wisdom that can be shared..!!
>>>
>>> -john
>>>
>>>
>>>
>>>
>>
>>
>
>
>