Date: Wed, 31 Jan 2007 23:41:34 -0500
Reply-To: Dennis Haynes <dhaynes@OPTONLINE.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject: Re: CSI: Vanagon...Smog results!
In-Reply-To: <8082912.1170298771714.JavaMail.root@elwamui-lapwing.atl.sa.earthlink.net>
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The crossover pipe on top of a giveaway. 1.9. The single pulley indicates it
most likely was a late '83 with the extremely early cooling system and it
may even have that odd ball 190 mm clutch and flywheel.
Now for your emissions failure results.
Your test is basically an idle speed and 2,500 rpm test. You failure was
both HC and O2. From a diagnostics point of view this is extremely valuable.
You r test results provide the justification for these testing programs. You
are a gross polluter putting out fumes like a Model T or a bad lawnmower.
As a recap for the group, the test limits are 1.2% CO and 220 ppm HC. These
are typical limits and all cat equipped vehicles should reach it, even
without a working cat. For information, the Dyno tests (IM 240) is used to
put the drive train under a sustained load to test for NOx production. This
tests the 3-way part of the cat, (CO, HC, NOx) and for engines so equipped,
the EGR function. Changes in ignition timing, gearing, compression ratios,
etc have adverse effects on NOx.
Anyway, your results were 9.99% CO, 1700 ppm HC at idle and 8.63% CO and 255
ppm HC at 2,500 rpm. The O2% was .2 at 2,500 and 5.6 at idle.
Normal atmosphere O2 is at least 19.5% these readings tell me the thing is
running real rich. There is obviously no O2 sensor control. The fact that
the HC drops at 2,500 rpm tells me there may also be an ignition, timing or
valve problem.
First thing to do is test the O2 sensor. Put meter on it. Measure between
the sensor lead and a good chassis ground. With things cold, when you first
turn on the ignition, you should see ~.6 volts. The is the leakage or bias
voltage on the ECU amplifier input. A cold sensor is an open circuit so you
will see that. Now start the engine. As the sensor warms, you may see the
voltage drop but it should soon increase. Since you are so rich, you should
see close to 1.0 volt or maybe more. If not, sensor is shot.
Next, after we know we have a good sensor, remove the cover from the AFM.
Disconnect the sensor from the ECU and connect it to the meter. Start engine
and watch voltage on sensor after it warms up. While engine is running,
gently turn AFM wiper opposite the direction the airflow is pushing it. The
engine should lean out and the sensor voltage should drop. Using the plastic
wheel, tighten return spring to get the sensor reading to around .5 volt.
Rev the engine and see if you can get it close to that voltage across the
range. The idle bypass screw can help get the idle speed tuned if needed. I
usually just set it 2 turns open and a properly functioning system will take
it from there. Re-connect the sensor to the ECU. You should be able to see
the sensor reading vary from .2 to.8 volts. You now have O2 sensor control.
If the throttle switch is working right, you can rev the engine to say 1,800
rpm, let go of the throttle, and see the O2 reading go to "0" for a moment
as the engine slows down. This is due to the fuel shut off when the engine
is above 1,300 rpm and the throttle is closed. Now, when the fuel is
resumed, the O2 sensor is ignored for 30 crank revolutions. This is why the
base mixture setting is critical. If the mixture is too rich without the O2
control, the engine will creep above the cut off speed, fuel is shut off,
the speed drops, and the cycle will continue. This is that famed Digi-jet
idle surge.
For the basic settings, make sure the distributor vacuum advance and retard
are both working. Set the timing at the correct setting, over advanced will
increase HC at idle. Set warm idle high at 950-1,000 rpm. Makes a big
difference. Make sure the auxiliary air regulator is working, getting 12
volts and closing quickly. If the basics are set correctly, you should no
problem passing those limits.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Joseph Fortino
Sent: Wednesday, January 31, 2007 10:00 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: CSI: Vanagon...
that thing is smoked out.. hard for me to tell
-----Original Message-----
>From: Paul Guzyk <paullist@GUZYK.COM>
>Sent: Jan 31, 2007 5:27 PM
>To: vanagon@GERRY.VANAGON.COM
>Subject: CSI: Vanagon...
>
>here's a game for all of you;
>
>can you tell if this engine is a 1.9 or 2.1 ?
>
>http://www.californiavan.com/burned/
>
>also, if you haven't done so already, replace all your fuel
>lines....this could be you !! :(
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