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[quk@isham-research.demon.co.uk (Phil Payne)]

In message <004901bd9a25$f3268fa0$ee5195c1@default> "DRoxburgh" writes:

> I ran the engine in the drive, wiggled then tugged the three wires attached
> together to the 'turbo' box - nothing - tried the braids at the front and
> rear of the rocker cover, and still running. It seems to happen after smooth
> braking to a standstill, I dont know if its connected to the whether its
> been raining, could be, but it seems to be happening more often. Have I
> pulled the right wires?

I have (empirically) said before: "Do not accept physical robustness as
proof of electrical continuity".  It may even have been in those words,
and it's probably in the archives somewhere.  I was most seriously
misled by John Robinson's car, which had perfect physical performance
in the coil ground and zero electrical performance.

Scott Mockry has been a little more objective and has suggested that
some circuits (most especially the WOT switch) need _LOW_ _RESISTANCE_,
not just continuity.  His figure of "less than 4 ohms in the WOT circuit"
has explained a lot of observed WOT phenomena - Orin Eman's WGFV test
light is a _vastly_ more reliable test of WOT functionality than any
electrical test on the switch circuit.

With a little thought, this becomes blindingly obvious.  The MB engine,
for instance, is grounded to the chassis in at least three places -
front braid, coil platform braid, and gearbox exhaust mount.  In spite
of this, Audi decided to ground the instruments directly to the engine
because they didn't trust the other grounds - even though there are
three in parallel - to provide low enough resistance.

--
 Phil Payne
 Phone: 0385 302803   Fax: 01536 723021
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