Only pumps fitted with a diode quench for the contacts or electronic
'points' are polarity-concious and should be marked with a '+' on the end
cap. They should only be fitted to negative-earth cars unless you convert
them - I am not sure if the 'electronic' pumps can be converted but the
diode quenched ones can by reversing the diode. 67 cars to NA spec should
be negative earth, 67 cars to UK spec could be either but +ve ground had a
dynamo and -ve ground had an alternator, check with a volt-meter if the
battery is not marked.
Pumps fitted with a capacitor quench work with either polarity.
If you take off the end cap you will see if it has points or not and what
type of quench is fitted - a capacitor can be buff coloured and marked
something like ".22uF 250v", a diode will probably be black with one end
(usually the +ve) marked with a coloured blob. Another check is to open the
points and connect a test lamp and ground to the pump. If the lamp doesn't
light with either the ground on the body of the pump and the test lamp on
the terminal or the other way round you have a capacitor quench. If it
lights one way but not the other then you have a diode quench, and it needs
to be connected such that with the ground on the body of the pump and the
test lamp on the terminal it does NOT light.
PaulH.
-----Original Message-----
From: Kevin Rarick <krarick@Oceania.com>
To: mgs@autox.team.net <mgs@autox.team.net>
Date: 03 February 1999 23:10
Subject: PC, and thanks
>"Polarity Conscious" - I want to ensure I connect power correctly to my
>newly installed SU fuel pump.
>OK, down to business :) The remaining step is for me to connect the power
to
>the fuel pump. I'm a bit leery about this as I don't want to ruin the pump
>right off by improperly connecting the power. Also, I haven't been able to
>find any specific directions for doing this. My car has a single 12v
battery
>and I haven't traced the cables yet to determine if it's positive or
>negative ground. I remember a fair amount of discussion a month back around
>this topic but I wasn't paying attention at the time. Oops. Of course I
want
>to be aware of the pitfalls, gotcha's, make-sures, dont-forget's, etc. Any
>guidance for this procedure will be greatly appreciated.
>
>Cheers,
>Kevin.
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