I'll have a remote water pump on the Duster and I'm trying to figure out the best way to wire it. I can wire it to the ACC circuit so it is on whenever the ignition key is on or in ACC. That would allow me to run it with the engine off if I wanted to cool the engine down.

I can wire it to IGN on so it is on when the key is on or the engine is on.

I can also use the EFI system to control it. For instance, I can program the ECU to turn the pump on whenever the engine is running (speed over 500 rpm). If I do it that way then it is a little more fool proof, but I can't turn it on with the engine off.

Does the water pump need to be run when the engine is off? Only reason I can think of is to help cool the engine down between rounds.

You could wire it through the fuel pump relay so
it has enough amps.. that is near the ECU

One of the local drag racers has a 160F temp. sensor installed in the fins of his radiator so it will turn on and off the water pump at 160F, I'm not sure if he has it wired into the ignition switch or not
He does commercial appliance repair here in Bend so he may have it set up so he can turn it on with the ignition switch on and have it turn itself off with the ignition switch turned off, I can ask him if you want to know

For between rounds and to keep the heads cool, I like the water pump & radiator fan to run whether engine's on or off, and I can run them independently of each other. Not sure what you have, I just have the old-school Moroso electric deal with Gilmer belt driving an OEM water pump.

Andy my Dart has the water pump relay controlled off the the ACC key switch and the fan on a controller with a temp probe in the tank.

Fan is set up to run when ever it is hot enough to need it. I also run a t-stat.

Lots of ways to do it, this works well for me.

I have a remote water pump. I put a pressure switch on the oil system so that as soon as there is oil pressure the water pump runs, to avoid accidental over heating.

Then I also ran a switch in the car that can turn the water pump on when the motor is not running, for between round cooling.

This works well for a bracket car.

If I were you I would use the EFI system.

Where you pull power is dependent upon how the car is wired.

If you have a BIG cable running from battery to alternator, grab or provide a bus point from alt charge stud.

If running OEM wiring, there is no good location to run the pump in both engine on or off configurations.

Andy I run mine off my ECU. It comes on at at 500RPM OR when the temp is over 120*. My high and low fans are also run by the ECU. When I get done making a pass I shut the engine off and turn the key back on, the fans and pump run until the engine gets down to 120* and then shut off. Makes it easy to manage engine temp without the fear of leaving them on for to long.

Since you have the ability, I suggest you drive it with the ECU in pwm mode. This way, you can always have some flow without temp surge.

I'd wire it to a relay and have the ECU ground it to turn it on bad on temp, rpm, whatever you like, but then also have a manual override switch that will pull the relay to ground to run the pump with the engine off.

Or this:

Simple rule with water pumps - if the engine is running - the pump must be on - that way you avoid steam pockets or hot spots away from the sensor - Also you should be able to turn it on when not running to cool between rounds - many of the new engines with electric water pump and fan actually can run when the engine is off - this allows for a conrolled cooling cycle to avoid heat soak

I am setting up a relay panel for the car to control things like the fuel pump, water pump, fans, etc. I will use ground switching as much as possible since it is safer than voltage switching.

I think I can use the ECU to control the pump and I think I can create a digital switch on the digital dash so I can turn the pump on even if the engine isn't running. Might take me a while to figure it all out though. Lots of new stuff to learn.........

Take a look at www.leashelectronics.com - I started using their boards - have them in both cars - made wiring very clean

Thanks, I'll take a look at that. I've been looking around for integrated solutions like that. I was thinking of going with the relay board from Auto Rod Controls but I'll take a look at Leash.

This is how I would do it with EFI...

I use a few of his relay boards for different things, nice stuff. Really nice product for the money.

Yeah that is kind of what I'm thinking too. I can also do the same trick with the transmission cooler. I have a sensor in the pan so the ECU can turn the fan on and off based on temp. The fluid doesn't move of course unless the pump is turning but I can still cool down the fluid that is in the cooler. The fuel pump is already controlled by the ECU with EFI so that is taken care of also. The car starts to get fairly automated at that point. I originally was going to put a switch panel in the car but now I've decided that I can get rid of the switch panel all together so I'll probably put it up for sale.

Yeah the Megasquirt really automated mine also. I have the factory key, line lock button, and a starter button. Not bad for running two fans, two fuel pumps, and an electric water pump.

I guess I miss read the post but on a race car I would run it
through the ECU and run the control through it.. I have
run Rampage run through it and a separate over ride on
the fan and pump on a heavy duty relay

I have considered this, I would need to add a solid state relay for the WP in my situation. I normally just run the water pump all the time, but in the winter it makes it hard to get engine temp up over 130 or so. It would be nice to slow it down to help build a little heat.

The thermostat is supposed to do that job, it can be a Hi flow stat as well.

For the OP, keep it simple. Id wire it triggered by the ign on. Then add a second switch to fire it at will when the engine isn't running.