RB26 OEM Boost Solenoid Valve terminals

[GodziRRa]

Hi guys,

Just looked at the FSM regarding the RB26’s oem pcm valve/boost solenoid. It says valve terminal 1 and 2, didn’t say wire color etc. I’m no electrician so I’m not really familiar with the symbols. One terminal has a black verical line as some sort of symbol. Anyone can tell which is which? Because I did get a 12v output on a terminal that’s supposed to have none. 😅 Terminal one is for the yellow and blue wire, or that’s the black and red wire? TIA!

[Duncan]

They kind of show it in the diagram, terminal 1 is the vertical part of the T and 2 is the horizontal/perpendicular.

But, why do you want to know? That Pin 1 should have power at all times when IGN is on, terminal 2 is pulsed by the ECU to control boost (ground signal)

[GodziRRa]

27 minutes ago, Duncan said:

They kind of show it in the diagram, terminal 1 is the vertical part of the T and 2 is the horizontal/perpendicular.

But, why do you want to know? That Pin 1 should have power at all times when IGN is on, terminal 2 is pulsed by the ECU to control boost (ground signal)

Because I got power at the horizontal terminal with the ignition on not the verical one. 
Just now I started the car, and at idle I’m getting 12v on both terminals. 🤷🏻‍♂️

[GTSBoy]

1 hour ago, GodziRRa said:

Because I got power at the horizontal terminal with the ignition on not the verical one. 
Just now I started the car, and at idle I’m getting 12v on both terminals. 🤷🏻‍♂️

There is no problem here.

Point 1. DC solenoids do not care which way that they are wired up. They throw the solenoid in the same direction regardless of current flow.

Point 2. The solenoid coil is just wire. If you put 12V permanently onto one side of it, and do not earth the other side of it, then the 12V will be measurable at both terminals. That 12V is actually measurable all the way down at the ECU. The ECU doesn't care. When the ECU decides that it wants that solenoid to operate, it provides the earth, by switching on a MOSFET (transistor) inside the ECU that will connect the solenoid terminal to earth (exactly as Duncan^ said). Now the solenoid has 12V being fed in one side and a convenient earth on the other side. Current flows, solenoidy things happen.

[GodziRRa]

3 hours ago, GTSBoy said:

There is no problem here.

Point 1. DC solenoids do not care which way that they are wired up. They throw the solenoid in the same direction regardless of current flow.

Point 2. The solenoid coil is just wire. If you put 12V permanently onto one side of it, and do not earth the other side of it, then the 12V will be measurable at both terminals. That 12V is actually measurable all the way down at the ECU. The ECU doesn't care. When the ECU decides that it wants that solenoid to operate, it provides the earth, by switching on a MOSFET (transistor) inside the ECU that will connect the solenoid terminal to earth (exactly as Duncan^ said). Now the solenoid has 12V being fed in one side and a convenient earth on the other side. Current flows, solenoidy things happen.

Thanks for that detailed solenoidy reply! Just confused why the supposed terminal that’s giving 12v (ignition on) isn’t giving me any, and the terminal that shouldn’t is giving one. 
If this is the case then we’re problem free. 😊 Some parts of that old FSM still confuses me.

[Duncan]

But, why were you checking in the first place? The IGN 12v at the boost control solenoid (terminal 1) also feeds a heap of other locations like the PCV, were you trying to sort a problem or just wondering?

The wiring from the ECU to the boost control solenoid is fine for use with a aftermarket ECU and solenoid if required (change the plug at the solenoid end to suit)

[GodziRRa]

17 hours ago, Duncan said:

But, why were you checking in the first place? The IGN 12v at the boost control solenoid (terminal 1) also feeds a heap of other locations like the PCV, were you trying to sort a problem or just wondering?

The wiring from the ECU to the boost control solenoid is fine for use with a aftermarket ECU and solenoid if required (change the plug at the solenoid end to suit)

I just replaced my old krusty solenoid. And since I tested the resistance of the new one, I also tested the wirings because I have a voltmeter in my hand… and I remember before that my mechanic had some rewiring done. 🙂