Hi Volks,

I wonder if someone out there has a scope and can look at the hash on
the B+ and maybe a sender lead like T-II or AFM?

I've been looking for example at the AFM lead, referenced to the
ground bolt by the ECU (2.1l) and it's sitting at a pretty constant
~2 volts with the engine idling.  But on that two volts is riding a
bunch of junk that I have to verify by examining B+, but I'm pretty
sure is switching hash from the alternator regulator.  There's some
regular squarish-wave oscillation that comes and goes at a few
hundred mV (and on the T-II signal, for example, where the base
signal is something like 0.1 V when the engine's hot, the oscillation
makes it average a couple tenths higher); but the most striking thing
I'm seeing is a regularly repeating pattern with more than 1.6
millisecs before a repeat.  It starts out with an underdamped wave at
4 mHz with p-p amplitude of EIGHT VOLTS for the first cycle or two,
then after that dies away the voltage gradually droops and then
descends in a smooth curve with minimum about -2 V, the same as the
bottom of the first cycle of the big spike.  There's some
low-amplitude (1-2 V) oscillation then the voltage gradually climbs
back up to the average value.  Total time is about 8 microsecs.

I'm not very happy seeing all that junk on B+, but it really bothers
me that it's leaking through the ECU into the sender inputs.  My
greatest concern is actually T-II, where as I said the average value
of the signal rises a couple tenths of a volt when you start the
engine, making it getting on for three times as high as it should
be.  I'm pretty sure my 1.9l didn't do that, as I had a Digitool
hooked to it for quite a long time.

Can anyone compare this with their own beast and give me a heads-up?

A year or so ago I was looking at what's on the alternator B+.  I'll
have to revisit that but whatever I was looking at I tried adding a
bigger capacitor on the output and it started ringing like crazy.  I
didn't have a big choke to try.

Thanks,
David