Date:         Tue, 16 Jun 2015 17:44:15 -0400
Reply-To:     Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject:      Re: 85 Westfalia Weekender fails Evap test.
Comments: To: Tyler Hardison <tyler@SERAPH-NET.NET>
In-Reply-To:  <CAP_Yzp++ADs5T=5VXpKQtbOjMOO9MQMc=rva58n1pTHrbJdGwQ@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

The easy way to test the evap system is to find a shop with a smoke generator. On the vanagon the common leaks are the vent and vapor lines above the fuel tank and gravity vent valves, seals on top of the expansion tanks in the wheel wells. Next is the purge valve and the lines to it and the carbon canister. 

For the emissions failure you need to offer some data. What did it fail for?
Carbon monoxide, (CO). Fuel began to burn but could not complete due to lack of oxygen or the oxygen could not reach the fuel vapor molecules. Mixture, incorrect ignition timing, bad injectors, fuel or air unbalance, oil getting where it doesn’t belong. 

Excessive Hydrocarbons, (HC). Fuel that didn’t burn at all. Lean or ignition related miss fire. Check for vacuum leaks, injectors again, Bad valves. 

Oxides of Nitrogen (NOx). Excessive combustion pressures or peak flame temperatures under load. Ignition timing, gear or tire changes, bad catalytic converter.  Vanagon does not have Exhaust Gas Recirculation, (EGR). 

Running catalyst should not have much to do to reduce CO and HC. It is needed for NOx. The O2 sensor is critical in this. The catalyst requires excess O2 (lean) to reduce the HC and CO. It needs an O2 deficient (rich) mixture to reduce the NOx. The O2 sensor system has to continuously switch between rich and lean so these 3 reactions can take place. 

Dennis



-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Tyler Hardison
Sent: Monday, June 15, 2015 6:02 PM
To: vanagon@GERRY.VANAGON.COM
Subject: 85 Westfalia Weekender fails Evap test.

I could go on and on about CARB and why they are the bane of my existence..
But I also like my air quality..

Anyway, took the Vanagon to the SMOG shop. They were nice enough to pretest without charging me.

Failed on the EVAP test, this is where they pressurize the fuel system and test for leaks. Any common places where I should look first before going from nose to stern looking for it?

Also failed on the emissions. Previous owner stated that they replaced the catalytic converter. I've done all of the vacuum hoses that I could find.
Complete ignition tune up and timing. I've also got an air-flow meter ordered as the one on the bus has been "compromised" (opened up).

Anything else I should play with?

-- Tyler

85 Westy Weekender