Toggle switch for efi fuel pump?

[koosh]

Been researching possibilities fir installing a toggle switch on the power wire going to an in tank fuel pump with a car that has efi.
Some results say: just install a 20 ano on/off toggle, others say the switch should be installed with a relay because of the possible high amp draw?
Manufacturer says my pump averages between 16-18 amps, but “could” go higher depending on “other electrical items” whatever that means…
I was thinking of using a high amp rated battery shut off switch?

 

[matthon]

Depends on the efi system, iirc.
My FiTech controls the in-tank pump, has a wire from the ecu specifically for it.

 

[RemCharger]

A buddy of mine on a 70 charger, used the defrost switch to power the pump. It is a low pressure carb FP though..

 

[gkent]

A relay is always a smart idea. A fuse between the relay and the pump. Trigger the relay with ground - that way you don't have 12 volts running through the switch.

 

[gkent]

I was thinking of using a high amp rated battery shut off switch?

WAY overkill !!!

 

[furious70]

Always a relay and the switch goes in the signal to the relay not the main power wire.

 

[furious70]

I'll add I've considered an interia switch too like OEM and I really should have one, everyone should

 

[matthon]

Prior generations of FiTech had the relay built into the ecu with a fuse.
No need for external relay.

 

[451Mopar]

Prior generations of FiTech had the relay built into the ecu with a fuse.
No need for external relay.

My FiTech 1200PA does not use a relay, the ECU powers the fuel pump with the option of Pulse Width Modulation (PWM). for pumps that need constant power I think you just set the PWM to 100% (It's been 10 years since I set it up, but I think that is how it was done?)

I don't know the posters setup is that he needs a switch. Every EFI system I have used has the computer turn the pump on and off, either through a relay or PWM like the Fitech.
For safety, you can add an inertia switch like they used in FORDs to cut power in case of an accident. Make sure to get the matching connector too.

If you want to manually control the pump, I would use a lower current switch on the control side of a relay.

 

[furious70]

My classic FAST mpi does not have that control, but it's an antique at this point

 

[Dennis H]

Is this about safety after a wreck?

 

[furious70]

I have a switch so that if I'm doing something else that requires the key on run I don't have to be running my battery down endlessly making laps with gas

 

[koosh]

I have a switch so that if I'm doing something else that requires the key on run I don't have to be running my battery down endlessly making laps with gas

This exactly my reasoning…. working on other issues needing key on and not have the pump cycle. The built in control on my MSD Atomic EFI works flawlessly, and they tell me i need no switch, but i don’t think they get what im trying to achieve.

 

[koosh]

Thanks for all the replies. Now this all takes a back seat, as upon my maiden test ride the pump HAS FAILED.
Being a “in tank” pump, i now have to drain and drop the tank for removal….
Another fun project

 

[matthon]

ECU powers the fuel pump with the option of Pulse Width Modulation (PWM)

To clarify, prior generations have PWM with an internal relay and an in-line fuse.

Current units have external relays, fuel pump and main power, and fuses.

Also, turn the key to run, fuel pump primes the tb then shuts off. It does not run continuously.