More Questions about SU Pump

[vette]

Hello Everyone, I have decided to keep my exiting pump at least for now. I think I'll carry a spare Facet for emergencies. So my existing pump has been workng fine but when I finish the reconstruction I will be going to a negative ground system. Can anyone tell me, Will this pump work on negative ground. I took the cap off and I see an electronic component soldered to the terminals. Was that put there by previous owner, or is that the way it was from new. I'm wondering is that a capacitor , or maybe a diode and will it work on negative ground. It has previously been operating as a positive ground. Thanks, Dave.

 

[andrea]

Hi Vette
Photos are not so clear -but it appear to me as be a condenser
so your pump easy work with Negative ground
NO inversion of pump wire is needed
Condenser are put in, to avoid sparks
but a better system is now the Transil Mod costs GBP4 +MAIL
see articles at page 17 18 19 of
ttypes.org/ttt2/pdf/download.php?issue=7 -<span style="font-weight: bold">or</span>
https://ttypes.org/ttt2/
August 2011-issue
I have it on my MG TD and on my 100/6 where my master PUM are the FACET and SU as ancillary
https://picasaweb.google.com/lh/photo/VtjfgmS_DXkIJ23iIY2_4tMTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/6WBWD-MYSSmOcWNFj6pRttMTjNZETYmyPJy0liipFm0?feat=directlink
https://picasaweb.google.com/lh/photo/HJWqrBODwTk1RTipu7ttXtMTjNZETYmyPJy0liipFm0?feat=directlink
Cheers
Andrea

 

[Bob_Spidell]

Looks like a capacitor, but probably not an 'original' (note the half-cylinder 'bubble' on the plastic cover for the electrical section; the original type capacitor was cylindrical as was the OEM diode). Some capacitors--electrolytic, for example--are polarity-sensitive; others--tantalum for example--are not. See if there's any '+' or '-' markings by the leads; if so you know it's polarity-sensitive. Usually, electrolytics are cylindrical and tantalum are disk-shaped, but there are many varieties.

I agree the transil is the best solution for a points-switched pump. I have one in my positive-ground pump; I believe it's a type of transil that is not polarity-sensitive (I got it from the MG guy).

 

[Keoke]

Another simple solution here is to use a Diode acros the points. For the SU Fuel Punp a 1N540X will work just fine.--Keoke

 

[Johnny]

I'm not certain but aren't the neg grnd pumps wrapped in a black tape and the pos grnd pumps with a red tape? I'm referring to the pump body wrap. You could just send an email to SU mfg in UK with the proper model number and I'm sure they'll know.

 

[Keoke]

No Because this pump has been tampered with.

 

[RAC68]

The SU fuel pump has been equipped with a number of different electronic components to reduce point flash and burn from over voltage. Unless there are marking on the component for identification, it is difficult to determine what the device is or whether it is original.

As I suggested in your previous thread, I would replace the installed component with a bipolar Transient-Voltage Suppression (TVS) unit (P6KE20CA TVS (manufactured by Vishay – Transil is another manufacturer of TVS components) purchased on-line from DigiKey for $0.15 per unit (minimum quantity - 4) + shipping.

Installation is relatively simple. One lead of the component is attached to the pump ground screw with the other lead secured under the top points screw-down.


All the best,
Ray (64BJ8P1)