Water Injection Trigger - Fuel Pump Trigger wire

[Kevin Doe]

I'm wiring up my water injection kit. Its activated by a boost switch. When boost hits the set level, it basically completes the circuit to the pump relay. I could hook this up to any +12V source, and it would work fine.

But, I would like to hook it up to a source that only has +12V when the car is actually running. Not when the car is off, or even in the on position. I want there to be zero possibility that the water injection can be triggered, unless the fuel pump is also running, and boost pressure is at the triggered value.

So, my question is what ECU pin, or what wire should I tap into. I think pin number 13 looks like the best candidate, but not too sure. I know I want to hook into one of the factory fuel pump relays wires, and I don't care if its the trigger wire, or the fuel pump output wire (because I've rewired my pump and added my own relay, so basically the factory relay triggers, then that output triggers my relay).

Is pin 13 the best source of this? Or is there another wire going to the gold box near the ecu under the radio that would be better? Can you give me a wire desctiption too (color and striping please).

Thanks,
Kevin

 

[doug]

Another solution might just be an arm/disarm switch. Coolingmist has them for $6.95:
http://www.coolingmist.com/detailpage.aspx?pid=31

 

[4wd-Eclipse]

Kiven, did you have warning/pick hold boost gauge like GReddy? if so you can use the YELLOW wire to give the NEGATIVE signal to the 12V relay when the desire boost pressure is reached. We have used this way in my friend supra to control the WI.

Anther option is http://www.coolingmist.com/detailpage.aspx?pid=09

 

[Chadillac2000]

Kiven, did you have warning/pick hold boost gauge like GReddy? if so you can use the YELLOW wire to give the NEGATIVE signal to the 12V relay when the desire boost pressure is reached. We have used this way in my friend supra to control the WI.

Anther option is http://www.coolingmist.com/detailpage.aspx?pid=09

Thats a good idea, only question I have is if you use the peak hold replay feature and it shows what your peak boost was, would that trigger the WI to go off even if the car was not infact at that level but you were just looking at your peak boost?

 

[4wd-Eclipse]

Thats a good idea, only question I have is if you use the peak hold replay feature and it shows what your peak boost was, would that trigger the WI to go off even if the car was not infact at that level but you were just looking at your peak boost?

The YELLOW wire is for the warning NOT for peak hold and you can set it up from the guage. Sorry I didn't mention that before. In our case we set the warning at 1.1 bar, so when the boost reach that level the guage activates the relay via the YELLOW wire. The YELLOW wire is connected to 85 in the relay and an ignition power source will be connected to the opposite one the 86.

I hope this clear

 

[Chadillac2000]

Oh alright. Much clearer. So by connecting the wire to the Yellow Wire on the you can set what psi you want the WI kit to activate by setting the warning light to what you want. For instance, you set the warning light to 1 bar and then when your boost hits 1 bar the WI kit starts spraying?

 

[4wd-Eclipse]

Oh alright. Much clearer. So by connecting the wire to the Yellow Wire on the you can set what psi you want the WI kit to activate by setting the warning light to what you want. For instance, you set the warning light to 1 bar and then when your boost hits 1 bar the WI kit starts spraying?