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Configuring Megasquirt for a DIYAutoTune.com Crank Trigger
Last Updated: 11/01/2007
This web page covers how to configure Megasquirt for our line of
36-1 trigger
wheels. See the
main
Megasquirt trigger wheel page for more details on the trigger wheels,
including how to install them on your car. In this article, we will use
the standard orientation described in the installation guide. Here's how
many teeth the gap should be ahead of the VR sensor to use the settings in this
article. You'll notice that the settings for 4, 6, and 8 cylinder engines
are the same as the settings on stock Fords.
| Number of cylinders |
Missing tooth location at TDC |
| 1 |
9 teeth ahead of the sensor |
| 2 |
9 teeth ahead of the sensor |
| 4 |
9 teeth ahead of the sensor |
| 6 |
6 teeth ahead of the sensor |
| 8 |
5 teeth ahead of the sensor |
| 12 |
8 teeth ahead of the sensor |
EDIS on a Megasquirt-I V2.2 Board
Using MSnS-E firmware
Hardware mods required:
- Remove D5, D8, R10, and the XG1-XG2
jumper.
- Jumper XG1 to the right hole of D5.
- Install a 1K resistor in place of D8.
- Run a jumper from the bottom hole of R10
and the banded side of the D9 diode.
- Use a 750 ohm to 1K resistor to connect
the right side of R23 to the negative side of D17.
- Run a wire from the negative side of D17
to X11 to bring the SAW output out on the DB37 pin 25.
External wiring:
- Connect the EDIS PIP signal to pin 24.
- Connect the EDIS SAW signal to pin 25.
MegaTune settings required:
Under Codebase and Output Functions:
- Set EDIS on, and all other code types off.
- Set LED17(D14) Function to Spark Output A.
- Turn off all other spark outputs.
Under Spark Settings:
- Set Trigger Angle and Trigger Angle
Ignition to 0.
- Set Cranking Timing to Trigger Return.
- Set Hold Ignition to 0.
- Set Spark Output Inverted to Yes.
- Do not select oddfire.
Under Dwell Settings:
- Specify Fixed Duty, 50% duty cycle.
The MSnS-E manual has a
detailed write-up about EDIS here. |
EDIS on a Megasquirt-I V3.0 Board
Using MSnS-E firmware
Hardware mods required:
- Remove C30.
- Run a jumper from the top hole of C30 to
S12C.
- If building the board from scratch, you do
not need to include D1 or D2, but they do not need to be removed.
- Replace R12 with a 1K resistor.
- Remove the XG1 to XG2 jumper, and jumper
XG1 to TachSelect.
- Jumper OPTOUT to TSEL.
- Connect a 750 ohm to 1K resistor from the
right side of R24 or the 5V hole in the proto area to the negative
lead of D14.
- Run a wire from the negative lead of D14
to the IGN jumper hole on the opposite side of the board to bring
the SAW output out to pin 36 of the DB37 connector.
External wiring:
- Connect the EDIS PIP signal to pin 24.
- Connect the EDIS SAW signal to pin 36.
MegaTune settings required:
Under Codebase and Output Functions:
- Set EDIS on, and all other code types off.
- Set LED17(D14) Function to Spark Output A.
- Turn off all other spark outputs.
Under Spark Settings:
- Set Trigger Angle and Trigger Angle
Addition to 0.
- Set Cranking Timing to Trigger Return.
- Set Hold Ignition to 0.
- Set Spark Output Inverted to Yes.
- Do not select oddfire.
Under Dwell Settings:
- Specify Fixed Duty, 50% duty cycle.
The MSnS-E manual has a
detailed write-up about EDIS here.
|
Distributor Based Ignition on a Megasquirt-I V3.0 Board
Using MSnS-E firmware
Hardware mods required:
- Build the VR
conditioner circuit, as described in Step 51 of the MegaManual. All
our preassembled Megasquirts with the V3.0 board come with this
circuit installed.
- Jumper TachSelect
to VRIN.
- Jumper TSEL to
VROUT.
- You may need to
adjust the VR trim pots, R52 and R56, when this is installed on a
running engine. A usual base setting is to turn them all the way
counterclockwise.
- Jumper IGBTOUT to
IGN to send to IGBT ignition coil driver signal out of pin 36 on the
DB37.
- Cut out R57 if
fitted (This won't be there on my units, though.).
- Get a 330 ohm 1/4w
resistor and cut the leads down to about 1/2" at each end. Maybe a
bit less.
- Tin each end of the
resistor with a bit of solder.
- Cut a 5" piece of
hookup wire (22ga is fine) and strip just a 1/8" or so. Tin the
stripped wire with solder.
- Melt the tinned
wire tip to one end of the tinned 330 ohm resistor tip and let it
cool.
- Heatshrink wrap
this wire/resistor assembly.
- Use this
wire/resistor combo to jumper the 'top' (top as in when you facing
the silkscreen side of the PCB, with the text so that you can read
it normally) lead of R26 to IGBTIN on the opposite side of the PCB.
External wiring:
- Connect the VR sensor to pin 24 and the
shielded ground wire.
- Connect the negative terminal of the coil
to pin 36.
MegaTune settings required:
Under Codebase and Output Functions:
- Set Generic Wheel on, and all other code
types off.
- Set LED17(D14) Function to Spark Output A.
- Turn off all other spark outputs.
Under Wheel Decoder Settings:
Some settings are the same for all engines.
- Wheel decoder base teeth: 36
- 2nd trigger enable: Off
- Missing Teeth: -1
- Dual dizzy mode: Normal
- Wheel decoder routine: 025 style
These settings are specific to your engine.
| Number of Cylinders |
Trig pos A |
Trig return pos A |
Trig pos B |
Trig return pos B |
Trig pos C |
Trig return pos C |
Trig pos D |
Trig return pos D |
Trig pos E |
Trig return pos E |
Trig pos F |
Trig return pos F |
| 4 |
3 |
8 |
21 |
26 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| 6 |
35 |
5 |
17 |
23 |
29 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| 8 |
35 |
4 |
8 |
13 |
17 |
22 |
26 |
31 |
0 |
0 |
0 |
0 |
| 12 |
2 |
7 |
8 |
13 |
14 |
19 |
20 |
25 |
26 |
31 |
32 |
1 |
Under Spark Settings:
- Trigger Angle: 60 (Exception: 6 cylinder
engines must use a trigger angle of 70.)
- Trigger Angle Ignition: 0
- Cranking Timing: Trigger Return.
- Set Spark Output Inverted:
Yes. Setting this wrong will damage the VB921.
Enable dwell control and adjust as needed to
match the coil you are using.
|
Direct Coil Control Distributorless Ignition on a Megasquirt-I V3.0 Board
Using MSnS-E firmware
Hardware mods required:
- Build the VR
conditioner circuit, as described in Step 51 of the MegaManual. All
our preassembled Megasquirts with the V3.0 board come with this
circuit installed.
- Jumper TachSelect
to VRIN.
- Jumper TSEL to
VROUT.
- You may need to
adjust the VR trim pots, R52 and R56, when this is installed on a
running engine. A usual base setting is to turn them all the way
counterclockwise.
- Jumper IGBTOUT to
IGN to send to IGBT ignition coil driver signal out of pin 36 on the
DB37.
- Cut out R57 if
fitted (This won't be there on my units, though.).
Now for constructing the
outputs...
- Get a 330 ohm 1/4w
resistor and cut the leads down to about 1/2" at each end. Maybe a
bit less.
- Tin each end of the
resistor with a bit of solder.
- Cut a 5" piece of
hookup wire (22ga is fine) and strip just a 1/8" or so. Tin the
stripped wire with solder.
- Melt the tinned
wire tip to one end of the tinned 330 ohm resistor tip and let it
cool.
- Heatshrink wrap
this wire/resistor assembly.
- Use this
wire/resistor combo to jumper the 'top' (top as in when you facing
the silkscreen side of the PCB, with the text so that you can read
it normally) lead of R26 to IGBTIN on the opposite side of the PCB.
- Now, you will be constructing duplicates
of this VB921 circuit for each coil output you need. For a 1
cylinder, you'll use 1 output; for more cylinders, you will use 1
output for every 2 cylinders. You can mount the additional VB921s on
a second heat sink stacked on top of the first, attached on top with
long screws. Or you can mount the VB921s to the case.
- Each VB921 will need a resistor-on-a-wire
assembly, running to its left leg. You will get the VB921 input
signal from the following locations:
| Output |
Input Location |
| Spark A |
Top of R26 |
| Spark B |
Top of R29 |
| Spark C |
Top of R27 |
| Spark D |
Bottom of R1 with R1 removed |
| Spark E |
JS7 |
| Spark F |
JS10 |
- The center leg of the VB921 is its spark
output. We have found that the IAC traces can carry enough current
for normal use, so you can use one IAC trace for each spark output.
You may need to add an extra connector on 12 cylinder applications.
This is our recommended pinout, which we use in our assembled ECUs,
for up to 8 cylinder engines.
| Output |
Board connection |
DB37 pin |
| Spark A |
IGN |
36 |
| Spark B |
IAC2B |
31 |
| Spark C |
IAC2A |
29 |
| Spark D |
IAC1B |
27 |
- Connect the right leg of each VB921 to a
ground, such as the proto area ground or SG pins. It's best if you
can find a separate ground for each VB921.
External wiring:
- Connect the VR sensor to pin 24 and the
shielded ground wire.
- Connect the negative terminals of the coil
to the pins specified in the above pinout.
MegaTune settings required:
Under Codebase and Output Functions:
- Set Generic Wheel on, and all other code
types off.
- Set one spark output for every two
cylinders.
- Turn off all unused spark outputs.
Under Wheel Decoder Settings:
Some settings are the same for all engines.
- Wheel decoder base teeth: 36
- 2nd trigger enable: Off
- Missing Teeth: -1
- Dual dizzy mode: Normal
- Wheel decoder routine: 025 style
These settings are specific to your engine.
| Number of Cylinders |
Trig pos A |
Trig return pos A |
Trig pos B |
Trig return pos B |
Trig pos C |
Trig return pos C |
Trig pos D |
Trig return pos D |
Trig pos E |
Trig return pos E |
Trig pos F |
Trig return pos F |
| 1 or 2 |
3 |
8 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| 4 |
3 |
8 |
21 |
26 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| 6 |
35 |
5 |
17 |
23 |
29 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| 8 |
35 |
4 |
8 |
13 |
17 |
22 |
26 |
31 |
0 |
0 |
0 |
0 |
| 12 |
2 |
7 |
8 |
13 |
14 |
19 |
20 |
25 |
26 |
31 |
32 |
1 |
Under Spark Settings:
- Trigger Angle: 60 (Exception: 6 cylinder
engines must use a trigger angle of 70.)
- Trigger Angle Ignition: 0
- Cranking Timing: Trigger Return.
- Set Spark Output Inverted:
Yes.
Setting this wrong will damage the VB921.
Enable dwell control and adjust as needed to
match the coils you are using. Set the dwell at a very low value to
start with (we've found Ford EDIS coils have especially short dwell
times) and increase it slowly. Back it off if the VB921s become hot to
the touch.
|
EDIS on a Megasquirt-II V3.0 Board
Using standard MS-II Firmware
Hardware mods required:
If you're
assembling your MegaSquirt-II from a kit
(Part#
MS230-K):
- Build the ECU up to trigger from the
Hall/Optical Input.
- Jumper JS10 to IGN to bring the ignition
output directly to pin 36.
If you're
modifying a DIYAutoTune.com MS230-C MegaSquirt-II Assembled ECU:
No mods are required; our units are set up for
EDIS out of the box.
External wiring:
- Connect the EDIS PIP signal to pin 24.
- Connect the EDIS SAW signal to pin 36.
MegaTune settings required:
Under "Base Ignition Settings," make the
following settings.
- Trigger Offset: 0 degrees
- Predictor Algorithm: Last Interval
- Ignition Input Capture: Rising Edge
- Cranking Trigger: Calculated
- Coil Charging Scheme: EDIS
- Spark Output: Going High (Inverted)
The MegaManual has a
detailed write-up on using MS-II with EDIS for further reading. |
Distributor Based Ignition on a Megasquirt-II V3.0 Board
Using standard MS-II Firmware V2.687 or higher
Hardware mods required:
If you're
assembling your MegaSquirt-II from a kit
(Part#
MS230-K):
- For the most
part, stick with the standard assembly documentation at
http://www.megasquirt.info/ms2/V3assemble.htm.
I'll just be covering any departures from that doc here.
- Step 51: You'll be
installing the VR input circuit (currently all steps under 51). You
do not need the components in step 50, although it's handy to
install them in case you ever use the Megasquirt on a different car
(or decide to convert your Mopar to a ignition system that uses this
circuit).
- Step 52: Set
the jumpers for VR input. That would be TachSelect to
VRIN, and TSEL to VROUT.
- Step 65: You will
use IGBT High Current Ignition Driver Circuit. That means you
complete step 65. Install everything just as this step directs
you to (which does mean no R57)
and install the jumpers to enable the circuit. (IGBTIN to
JS10 and IGBTOUT to IGN).
- That's it!
If you're
modifying a DIYAutoTune.com MS230-C MegaSquirt-II Assembled ECU:
Input Mod:
- You will be using
the VR input circuit. Connect the TachSelect jumper to
VRIN, and TSEL to VROUT.
Output Mod:
- There will be a
jumper wire from JS10 over to IGN. Desolder and remove this (don't
just cut it, you'll need the holes clear of solder).
- Install new jumper
wires to enable the IGBT High Current Ignition Driver Circuit (IGBTIN
to JS10 and IGBTOUT to IGN)
External wiring:
- Connect the VR sensor to pin 24 and the
shielded ground wire.
- Connect the negative terminal of the coil
to pin 36.
MegaTune settings required:
Note that on a 1 cylinder, you must set the
number of cylinders to 2 because there are still two ignition events per
engine cycle.
You will configure the input under the
"Advanced Ignition Options" page in MegaTune. Use these settings:
| Number of Cylinders |
Trigger Wheel Teeth |
Missing Teeth |
Skip Teeth |
Delay Teeth |
| 1 |
36 |
1 |
36 |
9 |
| 2 |
36 |
1 |
36 |
9 |
| 4 |
36 |
1 |
18 |
9 |
| 6 |
36 |
1 |
12 |
6 |
| 8 |
36 |
1 |
9 |
5 |
| 12 |
36 |
1 |
6 |
1 |
Under "Base Ignition Settings," you will need
to set Coil Charging Scheme to "Standard Coil Charge" and Spark Output
to "Going High (Inverted)" to configure it for direct coil control. You
will also need to adjust the dwell settings to match your coil.
More details about configuring MS-II for a
missing tooth wheel can be found in
the
"Missing Tooth Wheels" section of the MegaManual. |
|
