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Installing An Electric Fuel Pump in a T6 Car

September 27, 2010 | Troubleshooting & Repair

By Bob Slayden


When a car sits for a long period of time there is a tendency for fuel to evaporate from the carburetors, which can cause difficulties in starting. An electric fuel pump is one way to eliminate this problem. [Editor: A less expensive approach is a priming bulb. Another alternative is the Precision Matters "Primer Reservoir".].

Here are detailed instructions for installing an electric fuel pump in a 1962 or later 356 (For pre-1962 cars see this article). In this installation, the fuel pump is not intended to be used full time, so no pressure regulator is needed. Installation can be done in a couple of hours and is well worth the effort.

Installation in a T6 Car Placement of pump & wiring - view from wheel well
Placement of pump and wiring, view from wheel well
Placement of fuel lines
Placement of fuel lines Pump placement from below
Pump placement, view from below
Fuel line routing looking forward from wheel well
Fuel line routing looking forward from wheel well
Button before mounting under dash
Button before mounting under dash

Parts Needed

  1. JC Whitney Item #73ZX0906P-6v or #73ZX2807Y-12v
    [Ed: no longer available from that source, see below for other sources]
  2. 3-4" piece of heater hose
  3. 2-3 small fuel line hose clamps
  4. short section of fuel line about 24" long
  5. clear inline fuel filter
  6. 5-6 nylon tie-backs 8-12" long
  7. about 9' black 16 gauge automotive electrical wire
  8. inline fuse holder
  9. 2 wire connectors
  10. 1 small round wire terminal/end
  11. short piece 2-3" small diameter rubber tubing to protect wire from chaffing
  12. elongated spring loaded doorbell button from Home Depot, Lowes, Ace etc. about 3/4" x 2 & 1/2"

Tools Needed

  1. Drill for two 1/4' holes in front cross brace (3/16" bit optional wiring hole)
  2. pliers
  3. screwdriver
  4. wire crimpers

Notes

The pump offered by J C Whitney is rated (4.5 to 7 lbs) higher than the 356 needs. No risk of damage only of over powering the needle and possibly a somewhat rich mixture on starting, exactly what is needed. An original mechanical pump in good condition should be sufficient except for sustained very high speed driving since I haven't tested fuel flow at sustained maximum throttle. Not much chance of that in most of the US these days with crowded highways and radar.

Procedure

 

  1. Turn fuel lever to Z (Zu=closed)
  2. Jack up front of car or right side.
  3. Remove right front wheel.
  4. Remove fuel line from fuel cock. This would be a good time to check or rebuild fuel cock if it hasn't been done in umpteen years. This is not required for the electric pump installation though. Don't let fuel drip in your face! Stick a wooden pencil in the line to keep it from dripping.
  5. Position fuel pump on top of cross brace beneath the fuel tank and the front torsion bar tubes on the right side of car and mark for the two mounting holes (be sure to leave room for fuel lines to bend gracefully) drill 1/4" holes (see photos)
  6. Install the fuel pump on the cross brace. Wedge 3-4" heater hose between back of pump and cross brace as additional shock buffer for pump before tightening bolts.
  7. Cut short section of new fuel line and insert fuel filter in middle.
  8. Use this short section of fuel line to connect fuel cock to "in" port on pump. Attach with clamps. (see photos)
  9. Attach main fuel line to engine to "out" port on pump. Be sure fuel lines are neat and clear of steering damper. Use tie backs to position away from steering mechanism.
  10. Wire by connecting the new fuse link inline in a sort piece (about 6") of 16 gauge wire and connecting to terminal # 50 (the one with big red wire) on ignition switch. The button is "hot" at all times so pump may be activated before turning ignition key "on." Connect other end of same wire to doorbell button that will be fastened by double sided tape if needed (no screw holes etc.) on the inside of the lower lip of the dash panel just below the key. It is therefore out of sight but easily reached by curling your fingers around the dash lip and pressing on the button (see photo before placement under dash).
  11. Connect longer wire (about 8 1/2 feet) to other terminal on door bell button. Route long wire through firewall under dash adjacent to large existing wire bundle to the right of steering column crossing through to trunk. Inside the trunk, route wire behind fuse box and alongside of the bundle on driver's side of car to steering box access cover. Alternately you may want to drill a 3/16" hole under bundle into steering area to pass wire through. Loosen screws to steering box cover and pass wire into steering compartment below.
  12. Protect wire from chafing where it passes under cover with a short piece of rubber tubing and secure access cover screws. Route wire carefully avoiding steering mechanism and damper to pump and attach to terminal on the pump. Secure wire with tie-backs to prevent it from getting entangled in steering mechanism or steering damper.

Post Installation Notes

The pump is mounted "in-line" as it has check valves inside that allow the mechanical pump to pull through it without problems. Having the pump low (in the chassis) allows it to prime without difficulty and keeps it and the fuel filter safely away from engine/exhaust headers etc.

I only use it to prime the carburetors after the car has been sitting for some time. When you activate it, you can clearly hear the muffled "ticking" sound of the pump filling the carbs until they are full. Turning the key then results in immediate starting if all else is okay (ignition, battery, plugs, carbs, etc.) with much less wear on starter since it doesn't have to grind away filling carbs with the mechanical pump. Using the electric pump lessens battery drain as well.

Having it available only for priming avoids the risk of a pressurized gas stream should a fuel hose fail with much less risk of a fire. I have run briefly at or over 100 mph without fuel starvation with it in line. It is also useful on switchovers to reserve.

It will serve as a backup fuel pump if your mechanical pump fails. Keep a short piece of fuel hose in your spares to bypass the mechanical pump if its diaphragm blows and tape or wire the electric pump "on" full time to get home.

When I use the pump for starting my car, I generally have to run it about 20 to 60 seconds and occasionally longer on first start after sitting several days or longer, depending on how long the car has been sitting.

Bob Slayden
Atlanta, Georgia
Longterm custodian '62 Twin Grille Roadster #89696 with electric fuel pump, dual master cylinder, silicone brake fluid and 4-point seat belts

 





This list of vendors, in alphabetical order, is not necessarily comprehensive, and additional companies may also offer similar products. Note that where possible, links are provided directly to a specific product page if available.

NLA:  Electric Fuel Pump (6V or 12V, requires pressure regulator)

Zim's Autotechnik: Pierburg Low Pressure Fuel Pump 12V,  Electric Fuel Pump and Regulator 6V

5 Comments

Aa493c9f9299cdb0d51a6d201e2b655c 5331
John Pratt
February 02, 2011 at 11:05 PM
Great article. I followed your instructions to the letter (almost)! I used a Purolator/Facet 4.5 psi pump available from Car Parts Discount, http://www.carpartsdiscount.com/auto/parts/63/porsche/356b/fuel_pump/universal_electric_fuel_pump_4_5_psi.html?3593=125296. I bought an inline filter and 4 feet of 5/16 inch fuel hose and had more than enough length. <br />The placement is perfect, much more to my liking than behind the passenger floorboards. Thanks! :lol:
Profile missing thumb
Bruce Herrington
March 18, 2013 at 3:24 AM
Partly for ease of access, and partly due to concern about drilling holes in an 'original' 356, I always mounted electric pumps to the rear torsion bar tube, using hose clamps and suitable vibration absorbing rubber pad. Even in the SoCal Desert, I've had no problems with vapor lock in the long run from the front to the back of the car. Any ol' pump will do, for priming the carbs on cold starts, .<br /><br />Bruce Herrington
Aa493c9f9299cdb0d51a6d201e2b655c 5331
John Pratt
February 02, 2011 at 11:05 PM
Great article. I followed your instructions to the letter (almost)! I used a Purolator/Facet 4.5 psi pump available from Car Parts Discount, http://www.carpartsdiscount.com/auto/parts/63/porsche/356b/fuel_pump/universal_electric_fuel_pump_4_5_psi.html?3593=125296. I bought an inline filter and 4 feet of 5/16 inch fuel hose and had more than enough length. <br />The placement is perfect, much more to my liking than behind the passenger floorboards. Thanks! :lol:
Profile missing thumb
Bruce Herrington
March 18, 2013 at 3:24 AM
Partly for ease of access, and partly due to concern about drilling holes in an 'original' 356, I always mounted electric pumps to the rear torsion bar tube, using hose clamps and suitable vibration absorbing rubber pad. Even in the SoCal Desert, I've had no problems with vapor lock in the long run from the front to the back of the car. Any ol' pump will do, for priming the carbs on cold starts, .<br /><br />Bruce Herrington
Aa493c9f9299cdb0d51a6d201e2b655c 108
Alex Mestas
May 02, 2015 at 7:00 PM
I installed an electric fuel pump in my 63 356 B to prime the carbs. If my Coupe sits for more than 2 weeks there's a lot of cranking going on. I bought the "Kit" from Ed Rutherford at Klasse356.com who put the kit together for me. It contained every thing you need for the installation including great instructions. I didn't want the pump in the floorboard or in the engine bay. I had the pump mounted on top of the right diagonal brace since there is already a hole there for the bracket. Then they drilled a hole for the ground wire on the same channel and attach with a bolt and ring terminal. The hot wire of the pump is runs thru the brake light switch wire grommet above the master cylinder, following those wires up to the steering column and under the dash. I took Mike Wilson's recommendation and used an original sunroof switch as the my primer switch. The hot lead comes from the ignition switch. We picked up one of the connections next to the radio wire as it is only hot when the ignition is in the on position. We installed a fuse holder on the other wire from the switch ( the one leading back to the pump). It takes a 10 amp fuse. If you do use the sun roof switch, it just snaps into the rectangular hole under the dash to the left of the steering column. You can pig-tail the wire from two terminals to a single wire to the fuse so the pump can be activated either by pressing the switch to the right or left (open or close) mode of the switch. It's an 1.5 hour job. For those concerned with the authenticity of the appearance it's all reversible and can be removed as easily as it was installed. Using an original sunroof switch gave it the original touch. Thanks Mike for that great suggestion and instructions on connecting the switch.