Hi Ryan,
Oh yes, you're right, reversing the thermocouple connections
would reverse the output to the gauge.
I'm a bit curious about what you mean by
'bridging the
ground to either lead' for this, it doesn't want any other
ground applied. Doing so would provide another ground loop
and possibly give false readings.
I've drawn the sheathing and the amp (black) terminal joined
and to be treated as one wire, try it on the yellow and the
black, without crossing over the thermocouple wires. By
Using the sheath as ground at the thermocouple end, the fault
becomes irrelevant, so long as it is the only ground applied
to this unit and amp.
You would have to check (visually) that the sheathing doesn't
touch ground anywhere along its length, insulate if necessary,
maybe grommets would do, see what you think.
I have a friend here who is fairly familiar with this air cooled
volkswagen engine, he says its a 'boxer' engine (flat four) and
he would like me to mention some points that you may already
know. He says to change the head bolts for studs, as the bolts
can stretch with the extra load, also to mention that the heat
shield also helps to duct the air, some people remove it, they
think that will help the cooling, but actually it can make it
worse. Looking at the engine from the rear, he says that the
head on the left is the one that generally overheats, and to
pay extra attention to this one. Also that the standard fan
arrangement is not very good, and to consider changing it for
the porsche type fan arrangement, this may involve other mods.
Also he says that a 'Fast-road-cam' is about the maximum lift
reasonably, and that nossing is not an option on those heads,
it would just damage them.
please excuse the writing, i've just re-written this, i had a
TYPICAL 98se crash, just as i was posting, and i lost the well
written version of this. I am still fuming over it. I think
this PC needs more ram, i only have 64mb in there. I hope this
is written well enough to follow, just ask if its not clear!
If this cannot cure your mis-reading problems, then yes, you
will probably have to fit one of those little isolated supplies
that you spoke about before. I'm not very familiar with them.
Best of luck with it, John