Don

        So just to be ReallyClear on this ~ "upstream of the O2 sensor" ~ So the crack is

between the Eng' & The O2Snsr ~ If this is indeed the Case it is NOT a good thing for

your Eng's Performance or your O2Snsr ~ RawAir is MostLikely being pulled through the

crack into the Pipe & Causing the O2Snsr to think it is being exposed to LeanExhaust so

the ECU would then dump gas into the Mix to compensate & when you back off the Gas

it is conceivable that an ExtraShot of RawAir might get sucked in through the Crack &So

when you get back on the Gas a very Rich, maybe even FloodedCondition, is occurring @

which point the ECU just says ~ OK this is Goofy, I need a short break ~

        The Iffy Wires may indeed be contributing to the Issue but

~~~~~~~ YouReally NeedToFix ThatCrack ~~~~~~~

        & ~ Your O2Snsr should not be in 1 of your HeaderTubes ~ It should be located after

the Collector so that It "Sees" the Exhaust from All4 Cyl's ~

                                                                                        ORR ~ DeanB
On 25 Jun , 2014, at 10:24 AM, Don Hanson wrote:

> more...I may have the culprit...
> 
>  I removed my O2 sensor, which was a Denso Universal..It was adapted, with
> the Denso junction plug.... into a long flat VW plug on the motor end of
> the harness...4 prongs...3 from the O2 sensor to the brain and one (grey)
> from the harness plug to a ground nearby.
>  Of the three coming FROM the O2 sensor (two white, one black) the black
> lead was almost completely broken...or maybe it was and just touching now
> and again...   So that may have been the problem, certainly it was not
> functioning properly in that condition..
>    The O2 sensor itself:   It looks pretty strange in that it was covered
> with soot, most likely from idling while the exhaust warmed up to get it
> removed, but under that  thin soot, there was a thick caked white deposit
> covering the whole element...I don't know what these are supposed to look
> like but that doesn't seem right.
> 
>  So I have a new Bosch sensor..two whites and a blue with a round plug...I
> am going to splice that into the VW flat plug...putting the blue to the
> black and the white to white...the grey will go back to the block where it
> was before.
>  The Bosch sensor is different in that it has a perforated cylinder
> covering the element, I guess..but I think I got it as a specific VW
> sensor...
> 
>   I also found in my parts collection a good Temp II sensor (tested as per
> the Bently) a new red Bosch coil and an underneath throttle switch...(I
> think..on the inline VW motor the switch is 'concealed' below the throttle
> body...
> 
>   I am first going to change the O2 sensor and the Temp II sensor, see if
> that does it...
> 
>  Anyone have any comments?
> 
> On Wed, Jun 25, 2014 at 12:08 AM, Dennis Haynes <d23haynes57@hotmail.com>
> wrote:
> The symptoms clearing after cycling the ignition switch is classic of a
> problem with the O2 sensor or circuit. Sensors do get intermittent and they
> are easily fouled by road stuff on the outside and worse oil or antifreeze
> on the inside. Rich mixtures for any reason can also cause them to carbon
> foul.
> On the Vanagon Digifant another common problem is a bad ground for the O2
> reference circuit. One of these connections is the ground wire in the
> harness to the distributor. Check the archives. I have written the
> procedure to test the O2 sensor wiring in the past. If it can�t be found I
> can re-write.
> 
> Dennis