[Healeys] SU fuel pump polarity

[Bob Spidell]

Looks like they're both wired the same, and for neg. ground.  Try 
hooking them up to a 12V power source, and see which way makes them fire 
(pump).   If they don't run connected one way, try the other.  If it 
doesn't run right off the back disconnect lest you overheat the solenoid 
body.

Are both diodes labeled the same?

Bob


On 6/22/2018 3:18 PM, hspethmann at t-online.de wrote:
>
> My Healey:
>
> BJ8 MKIII 1964
>
> # L27347
>
> pos. earth
>
> Fuel pump for the last 20 years:
>
> SU AZX1307
>
> now with a slow, but steady clicking every 15 to 20 sec , when 
> ignition is on.
>
> I thought, the easiest solution is to change the pump with a spare 
> pump I have in my trunk for about the same time as the first one. Both 
> pumps look the same on the outside. Both pumps are wrapped in black 
> tape.  But the label on the box of the spare pump says: AZX1307 neg. 
> earth.
>
> In the archives I found a very instructive contribution by Steve 
> Russel from Aug 2009. And it ended with the words: "A picture would be 
> worth a lot of words right now."
>
> So I removed the cap on both pumps to see if there is any difference 
> in the wiring and took a picture, attached to this mail..  Both pumps 
> look the same inside. You see the old pump on the left, the new one on 
> the right.  Under the cap you see a piece that looks like a capacitor, 
> labeled as BZX1013. But following the explanation with terminal 1, 2 
> and 3 clockwise beginning with the power input stud and ending with 
> the internal ground terminal I suppose the "capacitor" is a diode. But 
> when there is no difference in wiring between the old and the new 
> pump, why could it be, that the old one looking like a neg. earth ran 
> 20 years in a car with pos. earth?
>
> I'm confused and hoping for your wisdom to shed some light on the problem.
>
> Best
>
> Achim
>
>  

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