Date:         Wed, 15 Mar 2006 14:48:02 -0800
Reply-To:     roger sisler <rogersisler2000@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         roger sisler <rogersisler2000@YAHOO.COM>
Subject:      1.9 runs better with 02 sensor disconnected-kinda long cause I
              need to ventialte
Content-Type: text/plain; charset=iso-8859-1

Imagin that. This is a new O2 sensor to boot.I get ocassional surging of about 200 rpms.Not too much, as recently I fought a much larger swing. Also it seems to run rich ,as I sometimes smell incomplete combustion exhaust when I shut it off and go round the rear, right afterwards.Also the idle is not as smooth as before.I hooked up a vaccum gage, and it shows no major problems,but the needle does vibrate about 1/3 to 1/2 inch of vaccum at 925rpms.

  When I disconnect this O2 sensor, the van runs great.No problems,but I know it wont pass the emissions test(got an extension till July-I told them that this was a rather rare vehicle and I had to mail order parts. Takes time ).I have checked the connection where the sensor connects to the wiring harness.Interestingly, the sensor wire from the sensor ,has only one wire. Where it connects to the wiring harness, this green wire has 2 wires. One is a ground. This connection is  clear of the ground wire.Anyone know what that extra wire(ground) is for?It is constructed like a coaxial cable. 1 wire surrounded by the other mesh wire ground(Sure would not like to have to splice this thing).

  I payed someone to remove and replace the old sensor,as I supposed the old sensor would not come out without a torch heating it up.Is this so? Never really tried.Will Mapp gas do the deed?How about 2 Mapp gas torches?

  Well, I would like to go ahead and get this van tested.Need to fix this sensor problem first.

  Another maybe unrelated problem, is that when cold, the engine will stumble at a stop light,sometimes dying, or after I hit the accelerator, seconds after the engine is first started it will stumble too.Restarting is not as ez as when warm or first started, either.It is like a carburated engine. I have to give it some gas to get it to start.When the van warms up, it dosent stumble, but sometimes I need to give it some gas to restart when I stall it out from bad clutch work.Clutch seems more sensitive too. I am stalling out more often.When i disconnect the O2 sensor, this stalling out seems less often.

  Could these be related? I remember reading that a carburated engine has some device that enriches the fuel delivery for a few seconds when the accelerator is suddenly let go.Like maybe when crossing a railroad track and then stopping quickly,half way (as this may then found to not be a smart idea). This device prevents the engine from stalling out. Forget what it is called.It riches things up, I believe. In a vanagon, this must be computer controlled, like the cold start enrichment.Perhaps my cold start enrichment function is cutting off prematurely? Maybe it is on too long and enriches the exhaust(like most all the time).

  ECU maybe? I removed and swapped the ECU without any difference. Two bad ECUs? I removed the water temp II switch and measured the temp/resistance  at different levels, and found it to be a good sensor.The AFM is grounded and has the tantalum capacitor. The auxillery airflow regulator was hooked up wrongly recently. I had mixed up the connectors to this and the throttle switch(Duh).Burnt out a switch($75 lesson).Perhaps the auxillery air regulator was damaged? I checked to see that it ran ok when the mix up was discovered.It did. Maybe this device was damaged internally? I blew air through ittoday, by attaching a hose from one end . Just a smidgen of air got through by blowing or sucking when the regulator was supposed to be off. Is this proper? I think all the vaccum hoses are ok as each is clamped and/or replaced. I checked over and over to see if they are the problem.Distributor vaccum advance system? I sucked and blew on the hose to this diaphram. Got to blow/suck real hard to
 get anythig out of it.Ok? I did find a hose to the distributor of the wrong size(too big), and changed it.Ignition timing?I put the van at  the bottom of a steep hill and drive up in too low a gear. No valve clacking, so the timing it likes ,must not be too far off.  By the way, the throttle switches work fine. The switch clicks on when at idle ok, and at full throttle.There is no adjustment for the throttle stop,as this is an early WBX throttle. The idle switch is adjusted to where it cuts off and on reliably. Not at .002 or .004 like the late WBX,as I just cant seem to fine tune it so it clicks proper.When cold or warm, the metal changes dimensions and the oils get stiff ,so clicking is iffy when finely adjusted.I get big time surging when this happens. I turned theidle switch screw in a bit more to get good functioning on/off.The large idle air screw(3/4 inch diameter) is turned in all the way and then backed off about 1/3 turn for throttle plate clearence. I need to turn it in
 this far, or the idle goes much too high.925 is the lowest idle I can get out of this throttle without messng with the timing.I removed the air filter , and I still get the rich exhaust.Exhaust leak?Havent checked recently,but it was good a few miles ago.Charcoal canister? I blew into this device and got little air to go inside or out.Water temp I switch? Havent checked it, but it seems ok at the dash. The secondary ignition is brand new(BD-thanks!) from the distributor cap to the spark plugs.The old platnium plus Bosh plugs showed light deposits  evenly on all 4 plugs.The new plug gap is .028.Thisjproblem occured before the change of secondary parts.Coil? Havent checked. Got a hot spark though.Fuel pressure?Got a new filter.I pinched the return hose and got no difference. I determined that the vaccum hose was properly connected to the pressure regulator.I do not know if the pressure is too high.Will disconnecting the vaccum hose lower the pressure?Dont want to swap this les I have
 to, as it is a bit*ch. Well thanks for letting me post this thick pile of paper. Sometimes when I do things like this, the answer comes to me. I am going with the fuel pressure regulator theory at this point.Gas mileage is muy bueno, though.18.3 city(urban).  I will sleep on it first for a few days, for the above reason.Do you have any ideas? Thanks again,Roger


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