Main Index of MS2-Extra Manuals

Layout of Components -- Suggested Supply points -- List of common components and part numbers

LS1 (Gen 3) trigger wheel

Internal Wiring -- Wiring Schematic -- MegaTune Settings

Available in MS2/Extra 1.0 and 2.x codes.
The Gen 3 LS1 motors use a 24 tooth crank wheel and a 1 tooth cam wheel. These can be used to fire the COP's in a wasted spark format by specifying the second trigger no-missing teeth. The crank wheel is the main trigger and and the cam wheel is the second trigger. These are both 5v signals so only simple interfacing is required. The second trigger is rising and falling.

ERRATA: December 2009 - we have found that "rising and falling" does not reliably work as desired. A new custom LS1 wheel decoder will be available in the MS2/Extra 3.0 alpha codes, but as a workaround, please try either "Rising" or "Falling" at cam speed.

V3.0 Internal Wiring:
Input Mods:

The following circuit would need to be made to interface the Cam sensor to the MS2 ECU

Output Mods for V3.0:

V2.2 Internal Wiring
Input Mods:

The following circuit would need to be made to interface the Cam sensor to the MS ECU, unfortunatly on a V2.2 PCB there is not enough spare terminals to bring this to the 37pin conenctor. It may be worth using the FIdle pin and removing the transistor for FIdle to acheive this.

Output Mods for V2.2:

Wiring Schematic

The LS motors all use coil near plug coilpacks, these need to be connected together in pairs in a wasted spark format because MS2 only has four spark outputs. The firing order is 1-8-7-2-6-5-4-3, so connect:

1+6 to Spark A
8+5 to Spark B
7+4 to Spark C
2+3 to Spark D

MegaTune Settings

The Trigger Angle/Offset is ignored in Toothed wheel mode, so leave it at zero. The angle used now is the angle that the next tooth (on the main wheel) is seen by the sensor after the 2nd trigger has pulsed. This is entered into Trigger Wheel Settings - Tooth #1 Angle.

Ignition Input is Falling Edge on the main trigger wheel (24 teeth) and the Spark output if using the Ignitors is Going Low. Set Dwell as above for Ignitior control. For Second Trigger active use Rising and Falling.

If using VB921's directly to drive coil packs use "Going High (INVERTED)" Also set Dwell to 3.2 Maximum Duration

Try setting the Tooth #1 Angle to 15, this should be fine, if not use the drawing below to work it out. (The value in theory should be 15deg but it could be 0 or 30 if the cam sensor is slightly off)

Below is an example of how to set up the Tooth #1 Angle but using a 60 toothed wheel, the theory is the same for a 24 toothed wheel, but the angle is 360/24 = 15deg between teeth, so 3 teeth would be 45deg, etc.

The quick-sync fast start tooth pattern is not yet utilised, but if accurate timing data of the wheel is supplied it could be.

Suggested points for Supplies inside the V3.0 ECU

Component Pinouts

Pull up circuit diagram

List of component part numbers used in the ignition section:

Please note: Above part numbers will need checking, some components will come with a minimum order in multiples of 5 and 10.

If you have a question, comment, or suggestion for this FAQ please post it on the forum.

No part of this manual may be reproduced or changed without written permission from James Murray, Ken Culver and Philip Ringwood.