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Date:         Mon, 5 Feb 2007 13:38:10 +0000
Reply-To:     dhaynes@OPTONLINE.NET
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject:      Re: CSI: Vanagon...Smog results!
Comments: To: William Greenamyer <greenamyer@YAHOO.COM>
In-Reply-To:  <vanagon%2007020508112938@GERRY.VANAGON.COM>
Content-Type: text/plain; charset=us-ascii

Below 1,000 rpm, air quantity and turbulence is too low to promote fuel mix. That is the main reason the idle ignition timing is designed to be so low. Advance the timing, and the fuel and air quantity has to be further reduced to maintain a low idle speed. As there is no after air injection reaction system, all combustion has to be in the engine or the Cat. Also, the proper spec is 850-950 rpm. Not 650. There are two versions of the idle stabilizer, Green and Black. I forget which but one of them does not do anything until the idle approaches 650. Virtually use less. The other one starts to advance the timing as the idle goes below 750. Still not much help.

Dennis

----- Original Message ----- From: William Greenamyer Date: Monday, February 5, 2007 8:22 am Subject: Re: CSI: Vanagon...Smog results! To: vanagon@GERRY.VANAGON.COM

> Below you say to set the idle RPM to 950-1000. That happens to > be where my > van (84GL) passes. It does not pass at Bentley value of 650RPM. > What is > happening at 950-1000 that is not happening at 650RPM? Is it > just the heat > of the CAT or is there something else we should be considering? > > William > > On Wed, 31 Jan 2007 23:41:34 -0500, Dennis Haynes > wrote: > > >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 > .... >


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