BACK TO PRODUCTS

Ok everyone, here is the new improved smoke switch idea.

First the diagram, then the wiring guide and explanation.

Click to view full size and print :)

How it works!


Once installed, when you push the switch it will activate the two relays.

One of them connects the MAP sensor input to a resistive divider voltage drop which will trick the computer into thinking there is about 36 psi of boost (according to my tst gauge).

The second relay will bypass the computers control of the wastegate AND open the wastegate fully at the same time.

The indicator light is NOT going to be on all the time. The light will only light when the computer tries to activate the wastegate, we are using an incandescent light for this to create the imaginary load the computer wants to see when it does this.


We have to use the DPST (dual pole single throw) switch to disconnect the bypass when it's running stock mode. Otherwise the ecu turning on the wastegate would activate the relays! IMPORTANT!!!


Both the stock circuits are on normally closed connections in the relays, so when the button isn't pressed, everything behaves as stock.

Parts needed

1 DPST toggle switch (auto parts store DPST make sure it says DPST)
1 Indicator light (auto parts store, like a universal idiot light)
2 standard Bosch automotive relays SPDT type. (5 connectors, auto parts store)
10 feet or so of 5 (or 6) conductor shielded wire (16 gauge or 18) (Home Depot)
2 wiring harness plugs for the relays (auto parts store, makes it much easier!)
Various electrical connectors
1- 117 ohm resistor (radio shack, low wattage is fine)
1- 15 ohm resistor (radio shack, low wattage is fine)

 

Wiring it up!

Disconnect the negative battery terminals from BOTH batteries!

Take the wiring harnesses for the relays and write down which color wire goes to which pin on the relay. They have little codes on the relays, (85,86,87a, 87 and 30). Those are important to the wiring of course!

Run the 5 wire cable from under the dashboard where you want the switch and indicator through the big wire harness grommet above the e-brake cable and into the engine bay. Find a good place to mount the relays and pull the cable through to that spot, zip tie everything down. Cut the spare cable off for use going to the wastegate solenoid.

Use a scotchlock (tap) connector to tap into the +5v supply voltage line for the MAP sensor (pink/yellow on mine), run that new wire through a 15 ohm resistor to pole 87 of relay 1. At that joint connect the 117 ohm resistor to another piece of wire to a ring connector and attach it to ground Also use this same ring connector or ground location to attach one of the wires going to the underdash. I'm using a bolt on one of the fuel line hold downs on the intake.

Cut the signal wire on the MAP (light blue on mine) and connect the wire from the MAP sensor side to pole 87A on relay 1.


Connect pin 30 of relay 1 to the ECM side of the MAP sensor signal wire.

Connect pin 85 on relay 1 to pin 85 on relay 2. Connect both of those wires to one of the wires in your 5 wire cable through to the underdash.

Run a section of the 5 wire cable from where the relays will be to the wastegate solenoid, please run this wire somewhere safe, like along the factory wires.

If it's gonna get hot, use good wire and cover it in wire loom. You are only using three of the five wires in this section.

Connect one of them with a tap connector to the grey/pink wire at the wastegate solenoid that shows +12V with ignition on.

Cut the other wire to the wastegate solenoid (dark blue) and connect each wire to a wire in the cable.

Make all your connections here good. I'd probably solder them at this point, heat shrink them, cover the cable in loom and zip tie everything into place. Don't want this wire melting or getting cut by the fan!

Back to the relays now.

Connect pin 86 on relay 1 to pin 86 on relay 2. Connect both of those wires to the +12v wire from the wastegate solenoid AND one of the wires going to the underdash.

Connect pin 87 on relay 2 to one of the 5 wire cable wires to underdash.

Find the wire from the wastegate solenoid that connected on the solenoid side of the dark blue wire and connect that to pin 87A of relay 2 AND one of the 5 wires going underdash.

Connect the wire from the wastegate solenoid that went to the ECM side of the dark blue wire and connect that to pin 30 of relay 2.

Ok, if I'm reading my own instructions correctly, that's it for engine bay wiring. Clean everything up, zip tie it all into place, make it look nice.

Move into the cab. Only a few more connections.

Hook up the wire that you grounded by the map sensor to BOTH input poles on the switch.

Connect the wire that went to both pins 85 on the relays to one of the output poles on the switch.

Connect the last output pole of the switch to the wire that went to pin 87a of relay 2 and the wastegate solenoid.

Connect the wire from pin 87 of relay 2 to the ground side of your indicator light.

Connect the wire from pins 86 on both relays and the power side of the wastegate solenoid to the positive side of the indicator light.

Mount your light and switch, clean up the wires, zip tie where necessary.

Reconnect both negative terminals on the batteries.

Go for a test drive!!! Let it warm up then try out the switch. It shouldn't build any boost and it should be fueling HEAVY... EGTs will probably go up some, but with no load and no boost it shouldn't be too bad. There should also be some nice heavy smoke!