Vanagon EuroVan
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Date:         Mon, 27 Dec 2010 16:47:39 -0500
Reply-To:     Ken Wilford <kenwilfy@COMCAST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Ken Wilford <kenwilfy@COMCAST.NET>
Subject:      Re: Progressive rough running - until ignition reset
Comments: To: John Rodgers <inua@CHARTER.NET>
In-Reply-To:  <4D18FB21.3040008@charter.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

John, check out this article I wrote about this exact problem in my newsletter:

Vanagon Oxygen Sensor Syndrome

Why is my van running like crap?

I have been having so many people call me lately with the exact same symptoms: Van is running extremely rich, bucking, losing power, and even visible smoke out of the tail pipe. The van will start up fine and run well until it is warmed up, then this starts happening. But if you turn the ignition off and then back on again while driving down the road the van will start to run good again for a minute or so. If you are experiencing this problem, I am here to say that I know exactly what the problem is and I can help you figure it out yourself without spending hundreds or thousands of dollars at the mechanic. The problem is in the oxygen sensor system. How I know that for sure is that when the van is started up, the computer looks at every sensor except for the oxygen sensor. It uses a built in reading for that until the van warms up. When you turn the ignition of and back on, this resets the computer and for a little while it runs off of the built in reading and then switches back to looking at the oxygen sensor readings again. Now that we know where the problem is, we can focus our talents on figuring out what part of the oxygen sensor system giving us a hard time. Grounds. First let's make sure that we have a good ground from the firewall to the cylinder head on the driver's side. There should be a strap there and it needs to be in good condition. If not, fix this first. Next there should be a ground connection that is coming out of the wiring harness that goes to the distributor and is also is grounding on the driver's side head in the same place as the ground strap. If you trace the wiring that goes to the distributor hall plug back about six to eight inches you will see this brown wire coming out of the harness. Be sure it is there and not broken, and has a good end on it and is securely fastened to the head. If not then repair this.

Oxygen sensor. Now that we know the grounds are good, the oxygen sensor itself is the next suspect. To test it simply unplug it from the fuel injection wiring harness. You should find the connector in the area below the ignition coil. Just trace the wire up from the oxygen sensor and you will find it. The oxygen sensor is located in the middle of the exhaust connector pipe for 1.9l Vanagons or in the catalytic converter for 2.1l Vanagons. If you unplug the sensor and the van runs better then you need a new oxygen sensor.

Wiring in FI harness. The most insidious part of this problem is that, more and more, I am finding this problem is caused by the oxygen sensor wiring inside the main FI harness. That means to fix the problem you are going to need to replace part of the FI harness itself. If you have done the other tests and you are still having problems then most likely it is with the oxygen sensor wiring inside the Fuel Injection harness (aka engine harness). It is a coaxial wire that has an inner signal wire and an outer shield. Over time the insulation between these two breaks down and now you are getting bad oxygen sensor readings sent to the computer even though everything is fine. You can check that this is your problem by unplugging the ECU from the ECU plug. In the 1.9l Vanagon the ECU is behind the driver's side rear tail light in the engine bay. In the 2.1l Vanagon the ECU is under the rear seat. Over to the driver's side you will see a black metal box. Take it loose from the firewall and flip it over and there is the ECU. Unplug it and look at the plug. You will see a small phillips head screw on the back side. Take this loose and cut the tie wrap that holds the plug to the harness. Now you can take the plug apart. You can gently pull on the center section of the plug while removing the cover. Once the cover is off, if you look at the plug more closely you will see it has numbers on it. For the 1.9l Vanagon you want look at pin number 5 or for the 2.1l Vanagon you want to look at pin number 2. This is the oxygen sensor signal wire and it should be green in color. Leave an inch or so and cut this wire. Tape the short end up and put the plug back together. The van should run great now with no rich running or bucking. You can run it like that forever. The oxygen sensor just fine tunes your mixture to give you best fuel economy. However many people are going to want to fix this right. We are offering a kit of wiring that you can just plug into your ECU in place of the wiring you just cut that will repair the problem permanently. The kit is $59.

On 12/27/2010 3:46 PM, John Rodgers wrote: > Volks, > > I have a general Vanagon troubleshooting question - today driving home > from an enjoyable Christmas gathering with all my family, the van > engine started twitching - a little skip at first, then as the miles > rolled it got worse and worse. I was sweating getting home in all that > snow and rain and raw weather we were having, and sure as heck didn't > want to stall out and spend time on the side of the road in that > weather. I managed to make it off I-65 at the southern exit onto Shelby > Co 25 on towards Columbiana. By the time I got to the last hill just > outside town - I was down to about 10 miles an hour, and coasted down > that hill into town to the main stoplight. The plan was to go through > the light on green, and pull over in a BigBox store parking lot. Didn't > get the chance. Light changed, and the engine stalled. I turned off the > wipers, the heater fans, and the head lights, shut off the ignition, and > then hit the switch again. She fired right up, purring like a kitten. No > more trouble......... until well up the road. Same thing over again. > Just a little twitchy at first, then got progressively rough. This time, > while coasting, I turned the switch off, and back on. The engine cleared > it throat, and purred like a kitten. Did it twice more before I got home. > > So - what could be happening that turning the ignition off and back on, > results in temporary clearing the problems. At first I thought fuel, > then some king of ignition trouble, then an electrical fault for sure. > Electronics somehow. > > Any ideas?? > > Thanks, > > John > > -- > John Rodgers > Clayartist and Moldmaker > 88'GL VW Bus Driver > Chelsea, AL > Http://www.moldhaus.com >

-- Thanks, Ken Wilford John 3:16 www.vanagain.com Phone: 856-327-4936 Fax: 856-327-2242


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