Simon,
I THINK the condensor (capacitor) is an electrolytic. If you keep it,
you'll have to
reverse the leads, else the first time you apply current you'll fry it
(probably to a
dead short, and possibly cause damage to your wiring). If it's any
other type,
it won't hurt to reverse it.
I've used "off-the-shelf;" i.e. standard diodes, with success. There's
not much
point in using a Zener--aka "avalance"--diode; they're used for
overvoltage protection
which you're not likely to experience. You'll need one with a quite
high current rating
(at least 3 amps@, say, 20+volts). Make sure you get the polarity
correct--diodes usually
have a silver paint "band" on the anode (+) side (Dave R, correct me if
I'm wrong here ;)
FWIW, this is called a "flywheel" diode and is common on a lot of
inductive loads (like
relays).
If it's not too much jack, I'd probably get one from SU ... they come
with terminals
attached and the leads should be marked red (+) and black (-). Make
sure you tell
them it's for negaive ground (though it won't matter if you get the
leads correct, the
terminals and leads might be a little different).
bs
Simon Lachlan wrote:
>Hi,
>
>I have a MkII BT7, which is not particularly relevant here as it has an
>AUF301 SU fuel pump which my manual says is from the "Later convertible
>model MarkIII".
>
>I have the pump in front of me as I type. It has a condenser (item 25 on
>page DDD.13 if you've got the same hymn sheet as me).
>
>So, when I take the car from positive to negative earth, what do I do to the
>pump?
>
>I've dug through my collated info on this topic and the collected wisdom is
>a bit contradictory:-
>
>1) Leave as is, but switch the leads around. Is that only for pumps
>with diodes fitted instead of condensers?
>
>2) Leave as is.
>
>3) Replace condenser with a diode.
>
>4) Replace condenser with Zener 20-28 volt diode.
>
>5) Fit a diode, CSX1004, is what Burlen Fuels (the SU people in UK)
>say. I suspect that they are just saying "Send money, NOW" but being polite.
>
>
>
>Maybe a CZX1004 is a Zener???
>
>
>
>What's to do here?
>
>
>
>Thanks,
>
>Simon.
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