On the Digifant, the ECU has absolutely nothing to do with spark advance.
Problem is in the distributor. The distributor has mechanical (centrifugal),
advance, and vacuum advance and retard.

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?

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