Fuel Pump Amperage

[TomoHawk]

Does anyone know the actual current under load of the Fuel pump on a 80Z when it's in operation?  If you wanted to install a kill switch of some kind it would be good to know, and I don't think it has a corresponding fuse.

[Chickenman]

The fuel pump should always run through a high amperage ( 40 amp ) continuous duty relay. The relay itself shouldn't pull much amperage. A 10 to 20 amp switch should be fine wired through the relay.  5 amps fuse is enough on the switch side. 

 A 25 amp fuse should be good enough on the fuel pump side.... for the stock fuel pump

Here is an article testing various aftermarket Hi Performance fuel pumps. Amperage draws are included. Note amperage draw was tested at 13.2 volts. If voltage at fuel pump is less than this figure, amperage draw goes up.

Make sure the fuel pump supply wire is of adequate size ( 12 gauge minimum ). Most factory wiring is not large enough for aftermarket pumps. Note that the Walpro 255 was not tested. It tends to draw more amps than other models, so plan accordingly. 

 

Edit: Forgot to include the link to the article.

http://realstreetperformance.com/Fuel-Pump-Comparison-Test.html

Edited May 1, 2017 by Chickenman

[TomoHawk]

So much for the "Just put a simple SPST switch on the fuel pump wire" system.

[Chickenman]

Well, the factory systme does run through a relay. So you can just wire in a simple SPST switch to the factory relay. I didn't know if you were doing a custom wiring job or what. 

[Zed Head]

Here's a chart from a company I've never heard of that felt confident enough to post what look like reasonable numbers.

http://www.autoperformanceengineering.com/html/fpspecs.html

 

Edit - realized after posting that the question might be a bit off target.  Fuses are designed to protect the wiring, not the device.  So, fuses would generally be specified by wire gauge of the power supply wire.  Like fusible links were, in the beginning.  And fuses are really just fusible links under glass.

Edited May 1, 2017 by Zed Head

[Zed Head]

Also, the fuse for the pump is the fusible link supplying the fuel pump relay.  It's one of brown links, 0.3 mm^2, the smallest.  So you could just remove the link itself and put the cover back on, for a short quick theft-proofing.  Looks like it supplies power to the air regulator and the pump and the ignition relay.

[TomoHawk]

A 30A relay in the back, (some have the fuse incorporated into the relay) and any small switch,  will be simple and fairly compact.  In case the relay fails, the use of certain connector terminals would make it so you could  bypass the relay, it it fails.

  Removing the fusible link will work, but those darned plastic covers break or become loose after you take them off so many times.