[Roadsters] Electric Fuel Pump

[Mark Sedlack]

Ron,
If adding an electric pump to a car that didn't have one originally, the 
below information is spot-on:

"Getting power to the pump involves adding a safety oil pressure switch so 
the pump only runs when the ignition is on and the oil pressure is up. This 
is done by installing an oil pressure switch from a Chev Vega (you may also 
need a couple of 1/8" pipe tees and short nipples if you also have an oil 
pressure gauge). These switches are available from most local auto parts 
stores. Three part numbers: NAPA (Echlin brand) p/n OP-6610 or Standard 
brand p/n PS-133 or Delco PS-9. While at the parts store, also get a 
standard sealed-beam headlight 3-prong socket connector. This connector fits 
the new oil pressure safety switch.

The switch has three prongs marked "I", "S" and "P." When there is NO oil 
pressure, the "S" and "P" are connected. When there is oil pressure, the "I" 
and "P" are connected.

The "I" wire is connected to the 12 volt side of the Ignition dropping 
resistor. The "P" wire goes up to the pump. Only one wire need be run from 
the back to the front. It is also a good idea to put a 5 amp fuse in this 
line. The "S" wire goes to the starter solenoid "S" terminal to energize the 
pump during cranking. The negative terminal of the pump is grounded to the 
pick-up tube with a clamp. (see Fig. A side view).


How does it work?

In the gauge installation, a wire runs from the pick-up terminal of the 
starter solenoid which is energized only when the key is turned to start the 
motor. The current goes through the normally closed (at rest) contacts of 
the oil pressure switch to the fuel pump (between contact "S" and contact 
"P"). When the engine starts and the oil pressure rises, the switch 
transfers, causing current flow from the ignition switch (contact "I") 
through the transferred switch contacts to the fuel pump (contact "P"). As 
long as oil pressure is maintained and the ignition is on, the pump keeps 
running. This is also an engine protection feature, if oil pressure is lost 
from an oil pump failure, the engine automatically shuts down."


I would add one other thing - its better to have the power "P" wire from 
above listed switch trigger a relay that feeds the pump instead of powering 
direct.  Some pumps can draw some serious amps.  Both my cars are wired this 
way.

Mark Sedlack
New Franklin, OH
66 1600 http://www.mildevco.net/chevypowereddatsuns/
77 280Z http://www.mildevco.net/chevypowereddatsuns/


----- Original Message ----- 
From: "Ronnie Day" <ronnie.day at gmail.com>
To: "Roadster List" <datsun-roadsters at autox.team.net>; "510 List" 
<bluebird510 at googlegroups.com>
Sent: Wednesday, July 31, 2013 10:41 AM
Subject: [Roadsters] Electric Fuel Pump


> Anyone have a specific suggestion for an electric fuel pump for the ('70
> 2000/SU) Roadster. Yes, I know I can go with an OE unit, but they run
> around $150 so I'm considering using an electric. I know it needs to be
> around 3 psi.
>
> Most of the ones I see with a quick search are high pressure unit for use
> with newer EFI systems. I seem to rememember Holley and S-W having 
> suitable
> models. I'll need a pressure switch, too, for the power if I go this 
> route.
>
> TIA,
> Ron