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Latest revision as of 04:27, 17 April 2026

General Setup

Crank sensor

07k crank sensor with plug

The 07K engine uses a Hall Effect crank position sensor. This is synced with the cam sensor for Dual Wheel Missing Tooth engine operation and VVT.

Crank sensor pinout

On the rear of the sensor plug the wires are numbered 1 through 3.

Pin 1: 5v.

Pin 2: Sensor output.

Pin 3: Sensor ground.

For best results this sensor should be shielded and kept away from sources of EMI like the starter, high-current wires, and any noise source.

For MegaSquirt, a pull-up resistor is needed for the ECU to recognize the signal. This is done by wiring a resistor between 5v and sensor output.

Incorrect wiring diagrams

07k vs 1.8t crank sensor comparison

This sensor is easily confused with the similar-looking 1.8t Variable-Reluctance (VR). Both are three-wire sensors. The 07k uses two small hex bolts and the 1.8t uses a single bolt.

In the wiring diagrams of both the 1.8t and the B series of engines (BGP, BGQ, BPS), the same sensor diagram is shown but different sensors are used. Per the diagram, both show the 3-wire VR sensor with VR+, VR-, and shield ground — this is incorrect for the 07k.

The C series of engines (CBTA, etc.) does not display a diagram for the sensor.

Cam Sensor

07k Cam sensor

The 07k uses a single Hall effect sensor on the intake cam. This is synced with the crank sensor for Dual Wheel Missing Tooth engine operation and VVT.

Cam sensor pinout

On the rear of the sensor plug the wires are numbered 1 through 3.

Pin 1: 5v.

Pin 2: Sensor output.

Pin 3: Sensor ground.

For best results this sensor should be shielded and kept away from sources of EMI like the starter, high-current wires, and any noise source.

Coil On Plug(COP)

Coolant sensor

2 Wire

3 Wire

Knock Sensor(s)

Throttle body

The 07k uses a drive-by-wire throttle body. To control it, you need a 3rd-party throttle controller called a DBW controller. Preferably wire the controller via CAN bus to the ECU to avoid extra wiring.

A DBW controller can be made using Arduino or purchased (e.g., ldperformance DBW or DBWX2).

Throttle body Pinout

Pin 1: TPS 1

Pin 2: TPS 2

Pin 3: Motor 1 - Brown

Pin 4: Output 5V

Pin 5: Motor 2 - Lilas

Pin 6: Ground

Map sensor

VVT

Accelerator Pedal

I have only messed with MK5 and MK7 pedals and they had identical pin layouts. They are as follows:

Accelerator Pedal Pinout

Pin 1: 5V^[1]

Pin 2: 5V

Pin 3: Ground

Pin 4: Output 1

Pin 5: Ground

Pin 6: Output 2

If you want to bypass the safety of having multiple 5v inputs, wire both 5v together. This can also be done with the grounds.

MegaSquirt 3X

**Please note that this is a work in progress, tune and wire at your own risk**

Ignition options / Wheel Decoder

TunerStudio ignition/wheel decoder options page

Coil on plug(COP)

Wiring diagram for COP^[2]

VW/Audi COP issue

The MegaSquirt3X cannot drive the VW/Audi coils directly. This is due to the SNx4AHCT541 IC being limited by the low trigger resistance (<1k ohm). Standard COPs are ~440 ohm, which causes excessive current draw, misfires, and potential EMI issues leading to RPM sync loss.

VW/Audi COP fix

The fix is to use three TC4427 ICs (scalable per cylinder count) and one 15 ohm resistor on each output.

MS3X ignition output modification circuit^[3]

Megasquirt VAG COP driver PCB^[4]

Drive by cable

Using a VR6 Throttle body

Male 8 pin plug going into throttle body

MS3X 2 wire PWM idle circuit^[5]

VVT

The VVT idle valve wiring can be found in the manual in section 3.5.4.4 (Page 47/225 MS3X/V3.57 Hardware Guide). This section has been copied below.

2-wire PWM idle valve (MS3X)

The MS3X connector allows direct connection of 2-wire idle valves.

MS3X VVT idle valve wiring diagram

Note the diode. The MS3X mid-current outputs are configured for low-frequency valves (e.g. boost or nitrous solenoids.) For high frequency valves such as idle valves or VVT solenoids it is necessary to connect a diode from signal to 12V in the loom. Alternatively a small jumper wire can be installed inside the case to make all outputs high-frequency capable - this is detailed in the assembly section. (c) 2014-8 James Murray 2018-08-01

Helpful links

@@ Line 138: / Line 138: @@
 [[File:MS3x VVT wiring diagram.png|left|thumb|MS3X VVT idle valve wiring diagram]]
-<nowiki>*</nowiki>Note the diode. The MS3X mid-current outputs are configured for low-frequency valves (e.g. boost or nitrous solenoids.) For high frequency valves such as idle valves or VVT solenoids it is necessary to connect a diode from signal to 12V in the loom. Alternatively a small jumper wire can be installed inside the case to make all outputs high-frequency capable - this is detailed in the assembly section. (c) 2014-8 James Murray 2018-08-01
+Note the diode. The MS3X mid-current outputs are configured for low-frequency valves (e.g. boost or nitrous solenoids.) For high frequency valves such as idle valves or VVT solenoids it is necessary to connect a diode from signal to 12V in the loom. Alternatively a small jumper wire can be installed inside the case to make all outputs high-frequency capable - this is detailed in the assembly section. (c) 2014-8 James Murray 2018-08-01
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