Hi Volks,

I checked out the harness this morning...

There are 4 white wires that go to the two injectors.
The shielding on the O2 sensor is grounded, and has no voltage. It is
trimmed to stop about 1/2 inch from the end of the core wire.
The core O2 sensor wire reads .44V
There is a brown wire to a clean and tested ground.
There is a white wire reading 13V - O2 sensor heater power.
There is a green/white wire reading .33V -- Where is this one supposed
to go?

Happy Trails,

Greg Potts
Toronto, Ontario Canada
197x Westfakia "Bob the Tomato"
1987 Wolfsburg Weekender Hardtop
www.pottsfamily.ca

BUSES OF THE CORN - AUGUST 13-15th, 2010
www.pottsfamily.ca\busesofthecorn

On 5/28/2010 5:45 AM, Dennis Haynes wrote:
> Sorry I missed the "Digifant" vs. "Digijet". The 2.1L Digifant does control
> the spark advance with the ECU. AFM and temp sensor are the primary spark
> advance signals. Since you are not seeing advance and you have the O2 sensor
> problem I suspect you have a ground problem. Possibly in the harness itself.
> The O2 sensor ground reference is also the ground wire in the distributor
> harness. The wire to the O2 sensor is a coaxial type wire, (inner wire outer
> shield). Pell back some insulation and check the outer shield for any stray
> voltage. With ignition on there needs to be no voltage between the shield
> and the chassis. If there is you have a problem. With the O2 sensor
> disconnected you should see about .5-.6 volt on that center O2 sensor wire.
> For the temp 2 sensor one wire goes to the ECU and the other goes to a
> ground. Another place for a bad ground connection.
>
> Dennis

>> -----Original Message-----
>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
>> Greg Potts
>> Sent: Thursday, May 27, 2010 5:36 PM
>> To: vanagon@GERRY.VANAGON.COM
>> Subject: Digifant timing/tuning help needed
>>
>> Hi Volks,
>>
>> My 1.9L digifant engine has been sluggish ever since I put it into the
>> bus back in September. It doesn't seem to make much power unless I wind
>> it out to 2.5K rpm or so. Fuel economy is nothing great either; I am
>> only getting 14MPG on a typical tank.
>>
>> Compression is good. (Around 150 on all 4 cylinders last time I checked)
>> Distributor is only 1 year old, as are wires, cap, rotor and plugs. If I
>> pull a plug wire off the distributor the idle staggers no matter which
>> plug wire I remove (ie, no weak link).
>>
>> Coolant temp sensor was replaced, it didn't help. O2 sensor is
>> disconnected until I get a new one; It's pretty much undriveable with
>> the O2 sensor connected. Throttle position sensor is working.
>>
>> So tonight I checked the timing. 5 degrees BTDC at 2K RPM with coolant
>> sensor disconnected. It's spot on at 2K rpm but as the revs increase the
>> timing stays rock steady at 5 degrees BTDC.
>>
>> According to http://www.oldvolkshome.com/ignition.htm the timing should
>> advance to 35 BTDC at 3K RPM....
>>
>> I have tried swapping the ECU and AFM with good spare parts and it makes
>> no difference whatsoever.
>>
>> Am I doing something wrong, is the ECU broken or am I reading more into
>> the oldvolkshome specs than I should?

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