ShopTalk Forums | Aircooled VW Tech & Restoration Help

I have a very silly question, but I figured I asked anyways. I'm mounting the fuel pump so that I can finnaly get the car started. I'm trying to figure out exactly where to get the juice from so that it doesn't drain too much from the system. I was thinking from the same side of the fusebox that cradles the windshield wiper's power. any other options? the instructions do not cll for a fuse, should i put in one anyways?
It's a CB performance 3.5# Carter pump.
Thanks for the help guys.


Sincerely,


Ephry

Ephry73 wrote:I have a very silly question, but I figured I asked anyways. I'm mounting the fuel pump so that I can finnaly get the car started. I'm trying to figure out exactly where to get the juice from so that it doesn't drain too much from the system. I was thinking from the same side of the fusebox that cradles the windshield wiper's power. any other options? the instructions do not cll for a fuse, should i put in one anyways?
It's a CB performance 3.5# Carter pump.
Thanks for the help guys.


Sincerely,


Ephry

personally i would never run an electric fuel pump that is not fused...i also like to put in a relay that kills the pump power when the oil light is on...you may want to also put in a bypass(around the relay) for times when the float bowl may be empty....
here is an excellent diagram for you courtesy of Speedy Jim..:
http://www.nls.net/mp/volks/schem/pump.gif

bugninva wrote:...i also like to put in a relay that kills the pump power when the oil light is on...

SpeedyJim's diagram uses the charging system warning light, not the oil pressure light - and that's actually better since if the relay fails the pump will stop. If you use a NC relay that opens when the oil pressure light comes on it's not fail-safe (if the relay failed, the safety feature would be gone).
Ephry, the best place to source the (fused) power varies with the model/year, but since with a safety relay it will only work when the charging system is working (or the button is pushed) you don't have to use power switched by the ignition. On `71-up cars that have an "X" terminal in the ignition switch, you can use that without risk of overloading the main (Term 15) contacts.
A FI Rabbit fuel pump relay can also be used; it has its own fuseholder on the end, and senses pulses from the points or pickup so that it will close any time the ignition is on and the engine is rotating, making the bypass switch less important. If you already have a tach, just tap the relay control lead into the tach signal wire.

Marc wrote:

bugninva wrote:...i also like to put in a relay that kills the pump power when the oil light is on...

SpeedyJim's diagram uses the charging system warning light, not the oil pressure light - and that's actually better since if the relay fails the pump will stop. If you use a NC relay that opens when the oil pressure light comes on it's not fail-safe (if the relay failed, the safety feature would be gone).
.

you are correct on both points...that diagram was for show...i actually use a relay that is made for the application...i bought the relay from a raceparts supplier that is local to me...it is required on the racecars we run at a local track... it actually plugs into the oil light, fuel pressure, or charging system and has mercury switch just incase the shiny side doesn't stay pointing up....

Thanks for the reply guys. This also works great. i had some replie on the T4 forum as well as from Bob Tomlinson himself.
I am definitely going to run the pump with an inline fuse, and when l get the right parts to do it right, l will then have the different sugestions and make up a "hook-up" as such. The warning light shut off sounds really sweet, as does the oil preassure one.
I also plan on running the pump from a sepparate fuse block that is relayed. For now, (since my Ghia is as 1972) is going off the ignition switched.


Ephry

P.S. Love the diagram guys!