Turbo water pump

[Drscottsmith]

I have converted this car to microsquirt engine management. My understanding is the extra electric pump and relay setup for the coolant flow to the turbo is independent, but on the wiring diagrams it does pass through the dme, among other places.

I wish MS had an extra output that I could use to control this pump but I am out. Should the system simply work with no dme connection?

I still have the temp sensor, pump, hoses and relay installed. Is there a bypass wiring of some sort that would at least get the 24-30 second running when car is turned off operational?

Thought about modifying a turbo timer type of device to just control the pump or even simpler a time delay relay board like this:

https://www.amazon.com/hz/mobile/missio ... T6O7A8SDXP

But I am not sure how to wire the trigger so that the timer would start when the engine was switched off.

Thoughts - I have read in at least one place that with modern oils and street use there really is no need for the pump at all.

Thanks

-scott

[Tom]

I have converted this car to microsquirt engine management. My understanding is the extra electric pump and relay setup for the coolant flow to the turbo is independent, but on the wiring diagrams it does pass through the dme, among other places.

I wish MS had an extra output that I could use to control this pump but I am out. Should the system simply work with no dme connection?

I still have the temp sensor, pump, hoses and relay installed. Is there a bypass wiring of some sort that would at least get the 24-30 second running when car is turned off operational?

Thought about modifying a turbo timer type of device to just control the pump or even simpler a time delay relay board like this:

https://www.amazon.com/hz/mobile/missio ... T6O7A8SDXP

But I am not sure how to wire the trigger so that the timer would start when the engine was switched off.

Thoughts - I have read in at least one place that with modern oils and street use there really is no need for the pump at all.

Thanks

-scott

The pump is controlled by the relay and the thermo-switch in the turbo coolant pipe. Not sure what you saw in the wiring diagrams (??) but the system should work as designed with the MS ECU --unless I'm more coffee-deprived than I realize right now. When the thrermo-switch gets hot enough, it sends a ground signal to the water pump relay, which turns on the pump for ~30 seconds. Likewise when the ignition is turned off, the relay sees that and turns on the pump for ~30 seconds. If you system is not working when the car gets hot and/or after you turn off the motor, see this relay troubleshooting video...

[Bergerac]

It definitely works without the DME, the pump stays on after the ignition and DME relay are de-energised.

For this reason it is hard to control with an after market ECU, you have to maintain the power to the ECU somehow and switch it off when the temp switch turns the pump off.

I'm working on it still with the S2 because that wiring is missing and is part of the body harness which is a lot of work to remove to modify. Link have a simple timer which allows you to keep an aux output on which you can used to maintain power to the ECU after the engine stops.

[Drscottsmith]

I am still using the dme relay to switch on the aftermarket control hardware, so that is still present. I would think if you gave the switched power as the control signal it might work but everything I can find starts the clock on power on, not off.

[Tom]

It definitely works without the DME, the pump stays on after the ignition and DME relay are de-energised.

For this reason it is hard to control with an after market ECU, you have to maintain the power to the ECU somehow and switch it off when the temp switch turns the pump off.

I'm working on it still with the S2 because that wiring is missing and is part of the body harness which is a lot of work to remove to modify. Link have a simple timer which allows you to keep an aux output on which you can used to maintain power to the ECU after the engine stops.

Just to clarify, I think you are saying it is hard to use an aftermarket ECU to run the fans after shut down (since the ECU is, well, shut down) and so it is easier to just use the factory control relay because it runs independently of the DME or ECU. I'd agree with that.

On your S2, if you are adding a turbo water pump (?) and struggling to replicate the turbo's post-shut down cycle, I'd be very inclined to just hand wire (mount it on the firewall with spade connectors) a factory turbo relay. All the wiring is explained in my video and that way there's no need to reinvent the wheel. You could get a 'turbo timer' for peanuts, but those keep the engine running and typically require some Fast n Furious controller in the cabin....

[Bergerac]

Ohh I can make it work, I just have to set the ECU Power hold timer to 5min which isn't really an issue because the ECU itself uses bugger all power. What im struggling with is the logic to power down the ECU when the fans and pump (it has a turbo) have reached a temperature setpoint because that logic stops the car starting again. Not sure this is possible at all with a MS unless they've added features I'm not aware of.

My fans and pump are both wired to a PDM, no more complex relays and resistors to mess around with anymore and I can change set points/duty cycles on the fly.

[Tom]

Ohh I can make it work, I just have to set the ECU Power hold timer to 5min which isn't really an issue because the ECU itself uses bugger all power. What im struggling with is the logic to power down the ECU when the fans and pump (it has a turbo) have reached a temperature setpoint because that logic stops the car starting again. Not sure this is possible at all with a MS unless they've added features I'm not aware of.

My fans and pump are both wired to a PDM, no more complex relays and resistors to mess around with anymore and I can change set points/duty cycles on the fly.

Maybe a little external hardware to cut it off after the sooner of reaching the set-point or XX seconds... ?

[944m3]

Has anyone found an alternative timed relay we can use? Mine is dead and it seems Porsche ones are no longer available.

I’ve seen timed relays as cheap as $20 on eBay. They appear to have the same connector pattern.