Electronics guys, switch question
Thread Starter
TECH Fanatic
Joined: Dec 2001
Posts: 1,220
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From: Germantown, MD
Electronics guys, switch question I need to setup a switch for my secondary fuel pump. Here is a diagram of my current setup.
Buschman's Fuel Setup
So you can see that the negative terminal was run all the way back up to the switch in the engine bay. I was told this is no better or worse than wiring up a relay and running the relay back up to the front. Any comments on that from the more experienced electronics pros?
Now because of the way my secondary pump is mounted I need to have a special kill switch. It's higher than the stock pump so there are times when fuel is low that I will want to make sure it doesn't engage if I happen to hit a little boost.
So I want a switch that has three positions. Pump always on, pump always off, and pump is boost referenced. What kind of switch should I use and how would I wire it up to accomplish what I'm trying to accomplish?
Thanks in advance,
Mike
Buschman's Fuel Setup
So you can see that the negative terminal was run all the way back up to the switch in the engine bay. I was told this is no better or worse than wiring up a relay and running the relay back up to the front. Any comments on that from the more experienced electronics pros?
Now because of the way my secondary pump is mounted I need to have a special kill switch. It's higher than the stock pump so there are times when fuel is low that I will want to make sure it doesn't engage if I happen to hit a little boost.
So I want a switch that has three positions. Pump always on, pump always off, and pump is boost referenced. What kind of switch should I use and how would I wire it up to accomplish what I'm trying to accomplish?
Thanks in advance,
Mike
Thread Starter
TECH Fanatic
Joined: Dec 2001
Posts: 1,220
Likes: 0
From: Germantown, MD
No one? I thought we had some cleaver electronics guys in here???
Help a brotha out.
Mike
p.s. Also how can I bridge a small 12 volt LED to display inside the car when the pump is running?
Help a brotha out.
Mike
p.s. Also how can I bridge a small 12 volt LED to display inside the car when the pump is running?
Just a comment on boost referenced switches controlling the relay.
HPTuners new software lets you drive relays based on different variables, one of which could be fuel pressure, I think thats a better idea than the boost way, because you won't always need to drive both pumps, only if your press drops below xx
HPTuners new software lets you drive relays based on different variables, one of which could be fuel pressure, I think thats a better idea than the boost way, because you won't always need to drive both pumps, only if your press drops below xx
Originally Posted by buschman
No one? I thought we had some cleaver electronics guys in here???
Help a brotha out.
Mike
p.s. Also how can I bridge a small 12 volt LED to display inside the car when the pump is running?
Help a brotha out.
Mike
p.s. Also how can I bridge a small 12 volt LED to display inside the car when the pump is running?
A single pole double throw switch should work. They usually have 3 connection points, one common wire that is then switched between the other to. If you wired the common to ground, one side the negative aux fuel pump and one side to the boost ref switch it should work.
In the middle position nothing would be grounded, in position one you would complete the pump ground and the pump would run all the time. In position 2 you would complete the ground to the boost switch which would come on only when you’re under boost.
I use this set up in my car when switching between 2 different fuel pumps (I have 2 separate gas tanks) in the middle no pumps run, pos 1 and pos2 switch between the 2 pumps. Same thing you’re looking for.
For the led wire the positive side to +12volt and wire the negative side to both sides of your switch. (So it gets grounded regardless of the position) You would probably want to put blocking diodes on the wires right before they merge with the switch.
This diagram may help
I am not a wiring expert but my car runs.
Mark
