MS-II Sequencer™ Set-Up

Your MS-II Sequencer™ EFI controller needs to be set up on 3 levels:

  1. Installation and Wiring - the physical setup,
  2. Tuning Software - to conform to your tuning PC computer,
  3. Tuning Parameters - to match the engine characteristics.

To install MS-II Sequencer™ EFI controller, you will need to physically mount it on the vehicle. You can do that using the four mounting holes on the flange of the case. Be sure to allow enough room for the harness to plug into MicroSquirt.

The wiring instructions are here: MS-II Sequencer™ Wiring Instructions, the tuning software set-up instructions follow, while the tuning parameters are discussed here: Configure/Tuning.

The tuning software for MS-II Sequencer™® EFI controllers is called TunerStudioMS (it is used with all variants of MegaSquirt).

You are all set up and ready to connect to your MS-II Sequencer! Note that MS-II Sequencer™ must be connected and powered up to communicate with TunerStudioMS on the laptop PC.

The tuning interface help file is on the web at:

The differences between MicroSquirt® and MS-II Sequencer™ User Inputs are as follow:

  1. The #set MS2_SEQ line must be in the settings.ini file and all other MegaSquirt® variants unset.
  2. As with MicroSquirt®, there is no injector PWM option.

  3. The Sequencer™ is meant to be used with toothed wheel, Dual Spark options 2-5 or 7-8: Falling/ Rising Cam sync, single crank wheel, single cam wheel, and falling/ rising edge crank signal with M-0 wheel crank tooth.

  4. The Sequencer™ is suitable only for engines with 3 8 cylinders, excluding 7 cylinders.
  5. To make the ReqFuel and duty cycle values correct , it is necessary to set the following parameters: Ignore the no squirt error warnings in the Injection Control setup, they don't apply to the sequencer.

  6. 'Calculated' should be used for the cranking trigger trigger rise is not supported and is not needed with a toothed wheel. It may work, but there may be extra pulses that may cause backfires.

  7. X-Tau works the same as normally, but during the transition from wasted to sequential, the time between squirts will double. This will result in a richer pulse width for a brief period because if the tau value is too short and the rpm too low when it happens, you will get a rich spike due to the fact that the cylinder is much drier when you squirt because it has waited twice as long for the sequential squirt. This is correct behavior, but if the engine has been tuned for wasted, you may have to increase tau a bit at the transition rpm.

  8. Port A0 and Port M3 can not be used as spare ports for the sequencer because they are used as a control line by the ECU to signal the sequencer processor when synch has been lost and when a new tach cycle begins.

    These have been replaced by 2 new spare outputs (they can even be used as PWMs when code is so written). These pins are on the Router processor and using them is completely transparent to the user. You use them just as you did A0 and M3, but wire to pins 31 (old A0) and 20 (old M3) on the second (output) Ampseal. In addition, a third GPIO/ PWM output from the Router, with 5 V pullup, was added on Ampseal pin 30. They can all be turned on/ off via a CAN message from the main processor to the Router. Hence, they can also be configured and controlled by a GPIO device. The following table summarizes this.

    Outputs                                 Function                         Control
      Router PT0                           GPIO                        ECU, CAN device
    (Ampseal O/P pin 31)              PWM                       CAN device
      Router PT1                           GPIO                        ECU, CAN device
    (Ampseal O/P pin 20)              PWM                       CAN device
      Router PT3, w pullup            GPIO                        CAN device
    (Ampseal O/P pin 30)              PWM                        CAN device

  9. You can only use ONE EGO sensor.

  10. The dual table option no longer has meaning because there are more than two injector banks. It could be used for a switch-over in case alternate fuel is used, but there is not at present any code to trigger the table switching.

  11. Set spark output as 'High to Low' same as MicroSquirt®.

  12. Odd angle should work for cylinders 4, 6 and 8,as well as 2 cylinders.

  13. Ignition option should be Standard Coil, you can't use EDIS.

New User Inputs for code version 3.343 are:

  1. ECU Type = 3 for the Sequencer™.

  2. Cam_Tooth. This is a user specified tooth number on the crank wheel with the significance that the cam synch must come after this tooth and before tooth no. 1. The numbering of the crank wheel teeth is such that tooth no. 1 is the first tooth after the missing tooth section. This allows the user to place cam synch anywhere on the crank wheel. Normally you would want to place it in the last quadrant before the missing tooth section, with Cam_Tooth defining a sector large enough that it is easy to place the cam synch and it will remain in the sector even at high rpm/ hi acceleration with excessive cam twisting. On the other hand, the smaller the sector the less probability of noise triggering a false signal. In setting the Cam_Tooth you must consider 2 cases. The first is when you have ECUType = 3 (Sequencer), Dual Spark option = rising/ falling edge cam synch, with a missing tooth crank wheel, on a 4, 6 or 8 cylinder engine. In this case set the Cam_Tooth as described, meaning a number from 1 to N M. In this configuration, the ECU will start the engine off in a temporary wasted spark mode, meaning it fires 2 coils and 2 injectors after each cylinder tach event. After it has achieved 8 cam synch verifies, meaning one rev with cam synch, one rev without cam synch, consecutively for a total of 16 =crank revs, then the ECU switches to sequential mode one spark, one injection per cylinder per 720 crank degrees and no longer looks at cam synch.

    Note that in Microsquirt cam synch is done differently and Cam_Tooth does not apply. With microsquirt , which gives sequential only for 1 and 2 cylinder engines, the cam synch must be placed to trigger somewhere within the missing tooth section, and the engine will be synched as soon as the missing tooth is detected, and whether a cam synch occurred in the missing tooth section or not determines which of the two outputs is fired first. So set Cam_Tooth = 0 if ECUType <= 2 or DualSpkOptn is NOT falling/ rising cam sync; otherwise, set it equal to a tooth from 1 to No_Teeth - Miss_Teeth.

    The second case for setting Cam_Tooth is when you are not configured as above, for example, no missing teeth, or a cam wheel, or 3 or 5 cylinder engine. These are cases where temporary wasted spark can not be achieved you must have a positive cam synch/ sequential mode before the engine is considered to be fully running. If this is the case, you MUST set Cam_Tooth = 0 and put the cam synch trigger in the missing tooth section. In this case a positive cam sync is required before engine synch. If there are no missing teeth, then tooth 1 is the tooth immediately after the cam synch occurs.

  3. Fuel and Spark Trims: These will work for 1-8 cylinders and are meant to be trims, but they are 16-bit words, and they have been tested to fairly large values like 100% and 40 deg. The resolution is 0.1 % and 0.1 deg. A +/-5% fuel trim is implemented by adding/ subtracting 5% to/ from the normally calculated VE correction. (For pure MAF VE would be 100%.+/- the trim) The spark trim is added to the normally calculated spark advance, so a negative trim number will retard spark. NOTE: trims are not used in any wasted spark mode, since you dont know which is the actual cylinder. In a wasted to sequential mode, for example, a mssing tooth crank wheel with cam synch, the trims wont take effect until the processor declares cam/synch/ sequential mode. (This wasted to sequential indicator has been added to the engine bit and is displayed through the ini file.)
  4. Spk_fuel_offset is the number of cylinders by which to offset fuel timing relative to the corresponding ignition cylinder. It must be a positive number from 0 to no. cylinders - 1. Using both this input and the existing injector % timing offset, one can start injection over all or most of the 720 deg engine cycle. It is intended for use only with sequential mode. Although it has been well tested, it is still a good idea to check the output fuel timing on a scope to make sure the timing is as you expect.

    The following shows an example for a 4-cylinder sequential engine. Sn and Fn denote the timing of the spark and fuel injection for cylinder n relative to a 12-1 toothed wheel. The start of fuel injection here is delayed relative to the spark by 1 tooth (30 deg) of 6 (16%) in the tach peroiod, and is specified by the user input InjStrt (as % of tach period). Then which cylinder gets injected is determined by the Spk_Fuel_Offset. The default is 0 so here cylinder 3 will get injected 30 deg after spark on cylinder 1. Selecting an offset of 3 would cause cylinder 2 to get injected instead. Note that the cylinder no. is the number in the ignition firing order, and that the Spk_Fuel_Offset does not change the fact that cylinder n still gets fuel trim n, even though its fuel injection order has been changed.

  5. Cranking Pulsewidth option: There are 3 Cranking Pulsewidth options (nskipCPW) which appear under the Fuel Menu, Start/ Afterstart selection. These are:

    Note that you must cycle power afterward if CPWOption is changed. Note also that there is no control of when injections begin during cranking when the simultaneous CPW option is used (because it makes no sense). Another thing to note is that fuel trim is not added into the cranking pulse width. Finally, when the mode changes from wasted to sequential during cranking, simultaneous CPW continues until past cranking rpm.

  6. tie1_2cyl: option (=1) to tie Ign1,2 outputs together either direct at the FETS or through a logic chip, or(=0) leave them separate and ignore one. Only applies for MicroSquirt in dual spark/ toothed wheel mode to 1 cylinder engines and 2 cylinder engines with wasted spark.

  7. Acknowledgement: This is NOT a user input and does not appear in the MSQ file. It is a flag that is sent via CAN from the ECU to the sequencer processor to signal that it is up and ready to go. It is a synch between the processors at startup.
  8. Added another MAF option for the case where there is a MAF and a MAP installed. In this mode MAF is used for fueling, but MAP is retained for the load index in spark and AFR target tables.

MegaSquirt®, MicroSquirt® and MS-II Sequencer™ controllers are experimental devices intended for educational purposes.
MegaSquirt®, MicroSquirt® and MS-II Sequencer™ controllers are not for sale or use on pollution controlled vehicles. Check the laws that apply in your locality to determine if using a MegaSquirt®, MicroSquirt® or MS-II Sequencer™ controller is legal for your application.
©2009, 2010 Bruce Bowling and Al Grippo and Lance Gardiner. All rights reserved. MegaSquirt® and MicroSquirt® are registered trademarks. This document is solely for the support of MegaSquirt® boards from Bowling and Grippo.