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How to MegaSquirt your Ford Mustang
Thanks and props to 'DieselGeek' for alot of help getting this
info together! You are the man!
Also-- if you haven't already, please read the 'disclaimer' at the top of the
parent page here.
Updated 2/21/2007 MSnS-E details on TFI and MSD control while
keeping fast idle control added

All 87-95 Fox Body
Mustangs
These have TFI modules on the
distributor (87-93) or remotely mounted (94-95). You can do these using
the PIP wire on the TFI distributor as the tach input to MegaSquirt-I running
MSnS-E firmware, or a MegaSquirt-II running the standard MS2 firmware.
More information on each implementation and any modifications required are
below.
87-93 5.0l Mustangs
Basically you get the TACH input to the MegaSquirt (pin 24) from the PIP
signal on the TFI module, and you send the outgoing MS ignition signal back out
from pin 36 to the SPOUT pin on the TFI module. I'll update this with more
info as time goes on-- it's totally possible to do this without the MSD box as
well, it just requires some mods. The mods aren't pretty on the MS-I with
MSnS-E, the mod is much easier on the MS-II.
94-95 5.0l Mustangs
Based on a remote mount TFI Module and a separate distributor. Same
story as the 87-93 for the most part, you just get the return the signals to
different places. Basically you get the TACH input to the MegaSquirt (pin
24) from the PIP signal on the TFI module, and you send the outgoing MS ignition
signal back out from pin 36 to the SPOUT pin on the TFI module.

Thanks to 'MegaScott' on the
MSEFI.com forums for this drawing and permission to use it here.
Using the MegaSquirt-I (MSnS-E) with a MSD 6A
Ignition Box on a TFI Vehicle
(such as the 87-95 Mustang)
This setup drives the MSD box through a VB921
transistor (for a V3.0 board) or 2N2222A (for a V2.2) and works with the stock
Ford fast idle valve.
MegaSquirt-I
PCBv2.2 Mods
Required:
-
Input mod: You install a 1k 1/4w resistor in
place of D8
-
Output mod: Run a jumper wire from the negative lead
of LED 17 to jumper X11.
-
Fast idle mod: Replace transistor Q5 with a
TIP120/121/122 power Darlington, as shown on our
MK-PWMIAC catalog page.
-
That's it!
MegaSquirt-I
PCBv3.0 Mods
Required:
-
Input mod: You install a 1k 1/4w resistor in place
of D2. Jumper TachSelect to OptoIn, XG1 to XG2, and TSEL to OptoOut.
-
Output mods:
-
Jumper IGBTOUT to IGN to send to IGBT ignition coil driver signal out of
pin 36 on the DB37.
-
Install Q16 if it is not already installed (Our
units will have this already soldered in).
-
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.

- Fast idle mods:
- Remove Q20 and D8.
- Remove R39 and install a jumper in its
place.
- Install a TIP120/121/122 in place of Q4.
For more information, see our
MK-PWMIAC page.
- That's it!
MSnS-E Ignition Configuration
-
Configur MegaTune for MSnS (NOT TFI) Spark Output using
LED17 (D14). (You'd only set it to TFI if
you weren't using the MSD box and had done the TFI mods)

- In MegaTune,
you MUST have “spark output" set to "inverted.”
- The
MSD box will control the dwell.
External Wiring

Here is an external wiring diagram for the V3.0
board. V2.2 wiring is identical except that you will connect the MSD white
wire to pin 25 instead of 36. Note that the fuses and relays are already in
the stock wiring, so you will not need to change these. The injector
configuration shown is intended to promote smooth flow through the fuel
rails and is one of several possible ways to wire the injectors.

|
Using the MegaSquirt-I (MSnS-E) with the factory TFI
Ignition
(such as the 87-95 Mustang)
MegaSquirt-I
PCBv2.2 Mods
Required:
-
Input mod: You install a 1k 1/4w resistor in
place of D8
-
Output mods:
-
Run a jumper wire from the negative lead
of LED 17 to jumper X11.
-
Get a 1k 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
negative lead of LED17 to the left pin of U5 to add a 12 volt
pull-up.
- Fast idle mod: Replace transistor Q5 with a
TIP120/121/122 power Darlington, as shown on our
MK-PWMIAC catalog page.
- That's it!
MegaSquirt-I
PCBv3.0 Mods
Required:
-
Input mod: You install a 1k 1/4w resistor in place
of D2. Jumper TachSelect to OptoIn, XG1 to XG2, and TSEL to OptoOut.
-
Output mods:
-
Run a jumper wire from the lead of D14 nearest the
DB9 connector to the IGN jumper.
-
Wrap a 1k resistor in a length of heat shrink
tubing, about 1" long, so that the leads of the resistor stick out both
ends of the tubing.
-
Use this insulated resistor to connect the S12
jumper hole to the IGN jumper to provide a 12 volt pull-up on the
ignition output.
-
Fast idle mods:
- Remove Q20 and D8.
- Remove R39 and install a jumper in its
place.
- Install a TIP120/121/122 in place of Q4.
For more information, see our
MK-PWMIAC page.
- That's it!
MSnS-E Ignition Configuration
-
Configure MegaTune for TFI Spark Output using
LED17 (D14).

- Set
Spark Output Inverted to Yes.
- Set
Trigger Angle to 10 degrees.
- Set
Dwell to Fixed Duty, and Spark Output Duty Cycle to 50% duty cycle.
External Wiring
Here is an external wiring diagram for the V3.0
board. V2.2 wiring is identical except that you will connect the TFI SPOUT
signal to pin 25 instead of 36. Note that the fuses and relays are already
in the stock wiring, so you will not need to change these. The injector
configuration shown is intended to promote smooth flow through the fuel
rails and is one of several possible ways to wire the injectors.

|
Using the MegaSquirt-I (MSnS-E) with a MSD 6A
Ignition Box on a TFI Vehicle
using the Fast Idle Output
for spark control
This is an older setup that is
somewhat easier to build, but does not offer fast idle support, nor does it
use quite as reliable a transistor to drive the MSD box as the VB921.
MegaSquirt-I
PCBv2.2 Mods
Required:
-
Input Mod: You install a 1k 1/4w resistor in place
of D8
-
Output Mod: None Required when using MSD 6a Box.
MegaSquirt-I
PCBv3.0 Mods
Required:
-
Input Mod: You install a 1k 1/4w resistor in place
of D2
-
Output Mod: None Required when using MSD 6a Box.
MSnS-E Ignition Config
-
Configured for MSnS (NOT TFI) Spark Output using
FIDLE (pin 30) (You'd only set it to TFI if
you weren't using the MSD box and had done the TFI mods)
<--- Click here for a closer look at the proper settings
-
In MegaTune,
you MUST have “spark output" set to "inverted.”


Thanks to 'stangdrvr' for the drawings and notes and permission to use them
here!
These diagrams are very useful if you are planning on running
your MegaSquirt using a MSD 6a box to provide the ignition signal.
There are a few changes to the second diagram as compared to the MegaManual on
the msefi site. These changes are TFI + MSD specific.
A1 = Connect to oxygen sensor, LM-1, or LC-1 output.
B2 = Connect to blue wire from TFI module.
C3 = Connect to coil outputs from MSD.
D4 = Connect to white wire from MSD.
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Using the MegaSquirt-II PCBv3 with the factory TFI
Ignition
(such as the 87-95 Mustang)

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 differentiation from that doc here.
-
Step 22: You really don't need any of the
5 jumper wires listed in this step. If you ever use this ECU on a
different car that does use a stepper motor IAC you can add them then.
Personally, I'd leave them out for your Mustang as you can use the IAC
outputs for other cool stuff later.
-
Step 50: You'll be installing
the 'Hall/Optical Input Circuit' (currently all steps under 50a).
If you see any steps that say 'only do this if you are triggering from the
negative terminal of the coil', you aren't, so don't. ;)
-
Step 51: You don't need these
components, but I'd recommend installing them anyways in case the MS ECU is
ever used on another car with a VR sensor.
-
Step 52: Set the jumpers for
Hall/Optical/Points. That would be XG1 to XG2, OPTOIN
to TACHSELECT, and TSEL to OPTOOUT.
-
Step 59: You will be doing the PWM Idle
Mod using the parts from the
mk-PWMIAC. That means you leave D8 out
when you get to this step.
-
Step 62: Follow the steps in the blue box
following step 62 to finish installing the
mk-PWMIAC for control of your 2-wire idle
valve.
-
Step 65: You ARE USING THE 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)
NOTE-- there was
originally an error in the MS2 TFI docs that said to leave R43 out for this
setup, I've found that to be incorrect and it's been corrected it in the MS2
docs, so LEAVE R43 in!
-
Step 69: Choice time -- Install the
PWM Flyback Circuit bits....
-
Step 71: Choice time -- Install the
current limit circuit for FET protection....
-
Step 74: Do not install Q20 (part of the
mk-PWMIAC mod)
-
Step 75: Leave R39 out and jumper it instead
(part of the mk-PWMIAC mod)
- Now for the final step (Mod for TFI Ignition
Output). Use a 100ohm, 1/4watt resistor. Solder
one leg of this to the IGN/IGBTOUT jumper wire. Solder the other
leg of this to the hole labeled S12.
(Not to be confused with the hole labeled
S12C !) The S12 label is on TOP
of the board, but you'll place this resistor on the bottom generally.
Check out this diagram.

Image
courtesy of Bowling and Grippo
That's it-- you've got your Megasquirt-II
Engine Management System fully prepared to receive the ignition input from your TFI module, and return the
Megasquirt controlled ignition output back to the TFI module giving you full
control of your stock TFI ignition system. At the same time you've also
'modded' the FIDLE output to be able to handle your Pulse-Width Modulated (PWM)
Idle-Air-Controller (IAC).

If you're modifying a DIYAutoTune.com
MS230-C MegaSquirt-II Assembled ECU:
Input Mod:
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)
- Use a 100ohm, 1/4watt resistor. Solder
one leg of this to the IGN/IGBTOUT jumper wire. Solder the other
leg of this to the hole labeled S12.
(Not to be confused with the hole labeled
S12C !) The S12 label is on TOP
of the board, but you'll place this resistor on the bottom generally.
Check out this diagram.

Image
courtesy of Bowling and Grippo
That's it-- you've got your Megasquirt-II Engine
Management System fully prepared to receive the ignition input from your TFI module, and return the
Megasquirt controlled ignition output back to the TFI module giving you full
control of your stock TFI ignition system. At the same time you've also
'modded' the FIDLE output to be able to handle your Pulse-Width Modulated (PWM)
Idle-Air-Controller (IAC).

Wiring it all up...
I couldn't possibly hope
to cover all of the wiring information that is so thoroughly covered in the
MegaManual here, and for the most part there's really no need to.
Sensors and Injectors wire up the same on most every vehicle out there...
You can use the
MegaManual's wiring section for this information. I'm going to
cover the Mustang specific stuff here.... that would be the Ignition Wiring
and the PWM IAC valve wiring. Those are the only two missing pieces of
the puzzle.
Ignition Wiring:
-
Input: Pin 24 on MS-II DB37, PIP from TFI module
-
Output: Pin 36 on MS-II DB37, SPOUT to TFI module

Image courtesy of Bowling
and Grippo
PWM IAC Wiring:
To wire this up without the relay board (directly to the ECU), wire up the
hot wire from the idle valve to switched 12v+ (hot in RUN), and wire the negative wire from
the idle valve directly to pin 30 on the MegaSquirt DB37.
To wire this up with the relay board, you will need to jumper the FIDLE relay to
take it out of the loop, below is a picture of how to do this. Then you will
still wire up the hot wire from the idle valve to switched 12v+ (you could use
the fuel pump power from the relay board), and wire the negative wire from the
idle valve directly to the FIDLE terminal on the relay board. This will allow
full control of your PWM idle valve.

Image 'borrowed' from the MSnS-E pages
You should also put a 1N4001 diode across the PWM Idle
valve itself - the banded end goes to the 12 Volt supply, the non-banded end
goes to the lead that goes to MegaSquirt (this diode is for flyback purposes on
the idle valve).

Megatune Ignition Configuration:
(from B&G's
TFI Control page for the MS-II)
- Trigger offset =
10° (this will vary,
depending on the distributor orientation, see below)
- Ignition Input Capture to 'Falling
Edge'
- Cranking Trigger to 'Trigger
Rise'
- Coil Charging Scheme to 'Standard
Coil Charging'
- Spark Output to 'Going
High (Inverted)'
Then set the dwell setting to 8.0 milliseconds
with no battery voltage compensation. This will get the spark output to
closely imitate the square wave signal that the EEC-IV computer sends out.
More information on setting Trigger Offset:
You must also set the initial position of the
trigger (called the 'trigger offset'), then check it using the Trigger
Wizard in MegaTune (Tools Menu). The trigger offset setting will
vary according to your distributor position (where it is in rotation) but
you'll need to set it properly... Basically you use the Trigger Wizard
and adjust the 'trigger offset' and/or twist your distributor until the
advance number in the Trigger Wizard matches what you're reading with your
timing light. The +/- buttons on the trigger wizard will adjust your
trigger offset. You'll need to use these buttons and a timing light to
make the number on your light, and the big number on the left in the Trigger
Wizard, match up.
Here's the information on this direct from the
MegaTune Manual:
Before tuning your advance table, be sure to use
a timing light to verify that your 'trigger offset' is calibrated.
Changing the Trigger Offset in MegaTune will not change the displayed
advance, instead, it changes the actual advance as seen with a timing light.
Your goal is to make these two match.
To do this, get your engine warmed-up (otherwise
the timing moves as the temperature increases) and idling, then use a timing
light to verify to be certain your actual advance as shown by a timing light
equals your the advance display on the advance gauge in MegaTune. (8° in
this case). (Note that positive numbers denote BTDC, and negative numbers
denote after TDC.)
 Image courtesy of Bowling
and Grippo
Megatune PWM IAC Configuration:
- First open the MegaTune Configurator, and open CAR1>SETTINGS.INI>SETTINGS>IDLE_CONTROLLER
and select PWM_GAUGE from the dropdown box at the top right.
- Save and exit the Configurator.
- Open MegaTune and connect to the ECU, and from the SETTINGS menu choose IDLE
CONTROL.
- Select the PWM Warmup ‘Algorithm’ and then you can configure the values
for your vehicle and click ‘Burn to ECU’.
Exactly how should these settings be tuned for the
Mustang's valve? I'll update this with working settings when I get
feedback from one of you guys, or get the time to finish the Mustang
'squirting here, whichever comes first. For now, information on tuning these settings can be found
in the MegaTune manual:
http://www.megasquirt.info/megatune.htm#sd
Coolant (CLT) / Intake (IAT/MAT) Temperature
Sensor Calibration
You can use your stock IAT and CLT sensors, and with the MegaSquirt-II you can calibrate these
sensors through MegaTune. It's best to leave the standard R4 and R7
'Bias Resistors' in place in the MegaSquirt and just configure this in the
software. You get better accuracy this way.
- Open MegaTune>Tools>Calibrate Thermistor
Tables
- Select 'Coolant Temp Sensor', Select
'Fahrenheit', and enter these values:

- Click OK and the Coolant sensor will be
calibrated.
- You're not quite finished yet though--- You
need to repeat these steps, but choose 'Air Temperature' as the sensor
table and use the same temp and resistance values from above as the
sensors use the same curve. This will calibrate the IAT as well.
NOTE-- Make sure you chose Fahrenheit or your
readings will be WAY off with the above values....

More Information
- Everyone should thoroughly read the
MegaManual. I mean... you wouldn't buy a new doo-dad and install
it without using the manual would you? OK now seriously though...
this is your pride and joy we're talking about here... read the
manual and the FAQ!!! www.megasquirt.info
- Read both the MS1 and MS2 sections, not
all of the MS1 section will apply to you, but MUCH of it will, and
the MS2 section isn't really complete without this information.
- Another great resource I refer to often is the
MegaTune Tuning Software Manual-- here's the link: http://www.megasquirt.info/megatune.htm
You shouldn't really 'need' this information, but
it's linked here for further reading if you're interested.
|
Using the MegaSquirt-II PCBv3 with a MSD 6A Ignition Box
on a TFI Vehicle
(such as the 87-95 Mustang)

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 differentiation from that doc here.
-
Step 22: You really don't need any of the
5 jumper wires listed in this step. If you ever use this ECU on a
different car that does use a stepper motor IAC you can add them then.
Personally, I'd leave them out for your Mustang as you can use the IAC
outputs for other cool stuff later.
-
Step 50: You'll be installing
the 'Hall/Optical Input Circuit' (currently all steps under 50a).
If you see any steps that say 'only do this if you are triggering from the
negative terminal of the coil', you aren't, so don't. ;)
-
Step 51: You don't need these
components, but I'd recommend installing them anyways in case the MS ECU is
ever used on another car with a VR sensor.
-
Step 52: Set the jumpers for
Hall/Optical/Points. That would be XG1 to XG2, OPTOIN
to TACHSELECT, and TSEL to OPTOOUT.
- Step 59: You will be doing the PWM Idle
Mod using the parts from the
mk-PWMIAC. That means you leave D8 out
when you get to this step.
- Step 62: Follow the steps in the blue
box following step 62 to finish installing the
mk-PWMIAC for control of your 2-wire idle
valve.
- Step 65: You ARE USING THE 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)
NOTE-- there was
originally an error in the MS2 TFI docs that said to leave R43 out for this
setup, I've found that to be incorrect and it's been corrected it in the MS2
docs, so LEAVE R43 in!
- Step 69: Choice time -- Install the
PWM Flyback Circuit bits....
- Step 71: Choice time -- Install the
current limit circuit for FET protection....
- Step 74: Do not install Q20 (part of
the mk-PWMIAC mod)
- Step 75: Leave R39 out and jumper it
instead (part of the mk-PWMIAC mod)
That's it-- you've got your Megasquirt-II
Engine Management System fully prepared to receive the ignition input from your TFI module, and return the
Megasquirt controlled ignition output out to your MSD 6a CD Ignition box--
Giving you full control of your fuel and ignition!. At the same time you've also
'modded' the FIDLE output to be able to handle your Pulse-Width Modulated (PWM)
Idle-Air-Controller (IAC).

If you're Modifying a DIYAutoTune.com
MS230-C MegaSquirt-II Assembled ECU:
Input Mod:
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)
That's it-- you've got your Megasquirt-II Engine
Management System fully prepared to receive the ignition input from your TFI module, and return the
Megasquirt controlled ignition output out to your MSD 6a CD Ignition box--
Giving you full control of your fuel and ignition!. At the same time
you've also 'modded' the FIDLE output to be able to handle your Pulse-Width
Modulated (PWM) Idle-Air-Controller (IAC).

Wiring it all up...
I couldn't possibly hope
to cover all of the wiring information that is so thoroughly covered in the
MegaManual here, and for the most part there's really no need to.
Sensors and Injectors wire up the same on most every vehicle out there...
You can use the
MegaManual's wiring section for this information. I'm going to
cover the Mustang specific stuff here.... that would be the Ignition Wiring
and the PWM IAC valve wiring. Those are the only two missing pieces of
the puzzle.
Ignition Wiring:
-
Input: Pin 24 on MS-II DB37, PIP from TFI module
-
Output: Pin 36 on MS-II DB37,
connected to white wire (points trigger) on the MSD 6a box

Image courtesy of Bowling
and Grippo
PWM IAC Wiring:
To wire this up without the relay board (directly to the ECU), wire up the
hot wire from the idle valve to switched 12v+ (hot in RUN), and wire the negative wire from
the idle valve directly to pin 30 on the MegaSquirt DB37.
To wire this up with the relay board, you will need to jumper the FIDLE relay to
take it out of the loop, below is a picture of how to do this. Then you will
still wire up the hot wire from the idle valve to switched 12v+ (you could use
the fuel pump power from the relay board), and wire the negative wire from the
idle valve directly to the FIDLE terminal on the relay board. This will allow
full control of your PWM idle valve.

Image 'borrowed' from the MSnS-E pages
You should also put a 1N4001 diode across the PWM Idle
valve itself - the banded end goes to the 12 Volt supply, the non-banded end
goes to the lead that goes to MegaSquirt (this diode is for flyback purposes on
the idle valve).

Megatune Ignition Configuration:
(from
B&G's MSD 6a Control page for the MS-II)
- Ignition Input Capture to 'Rising
Edge'
- Cranking Trigger to 'Trigger
Rise'
- Coil Charging Scheme to 'Standard
Coil Charging'
- Spark Output to 'Going
Low (Normal)'
- Maximum Spark Duration to '25.5'
Under the dwell settings:
- Maximum Dwell Duration to '25.5'
To set the dwell to 25.5, you'll have to change one
of lines in the megasquirt-II.ini file. You'll find this file in
C:\Program Files\MegaSquirt\MegaTune2.25\mtcfg
Edit the following line: (use
CTRL-F to search for max_coil_dur to find the line)
max_coil_dur = scalar, U08, 4, "ms", 0.10000,
0.00000, 1.00, 8.00,
1 ; * ( 1 byte)
to
max_coil_dur = scalar, U08, 4, "ms", 0.10000,
0.00000, 1.00, 25.50,
1 ; * ( 1 byte)
You must also set the initial position of the
trigger (called the 'trigger offset'), then check it using the Trigger
Wizard in MegaTune (Tools Menu). The trigger offset setting will
vary according to your distributor position (where it is in rotation) but
you'll need to set it properly... Basically you use the Trigger Wizard
and adjust the 'trigger offset' and/or twist your distributor until the
advance number in the Trigger Wizard matches what you're reading with your
timing light. The +/- buttons on the trigger wizard will adjust your
trigger offset. You'll need to use these buttons and a timing light to
make the number on your light, and the big number on the left in the Trigger
Wizard, match up.
Here's the information on this direct from the
MegaTune Manual:
Before tuning your advance table, be sure to use
a timing light to verify that your 'trigger offset' is calibrated.
Changing the Trigger Offset in MegaTune will not change the displayed
advance, instead, it changes the actual advance as seen with a timing light.
Your goal is to make these two match.
To do this, get your engine warmed-up (otherwise
the timing moves as the temperature increases) and idling, then use a timing
light to verify to be certain your actual advance as shown by a timing light
equals your the advance display on the advance gauge in MegaTune. (8° in
this case). (Note that positive numbers denote BTDC, and negative numbers
denote after TDC.)

Image Courtesy of Bowling and Grippo
Megatune PWM IAC Configuration:
- First open the MegaTune Configurator, and open CAR1>SETTINGS.INI>SETTINGS>IDLE_CONTROLLER
and select PWM_GAUGE from the dropdown box at the top right.
- Save and exit the Configurator.
- Open MegaTune and connect to the ECU, and from the SETTINGS menu choose IDLE
CONTROL.
- Select the PWM Warmup ‘Algorithm’ and then you can configure the values
for your vehicle and click ‘Burn to ECU’.
Exactly how should these settings be tuned for the
Mustang's valve? I'll update this with working settings when I get
feedback from one of you guys, or get the time to finish the Mustang
'squirting here, whichever comes first. For now, information on tuning these settings can be found
in the MegaTune manual:
http://www.megasquirt.info/megatune.htm#sd
Coolant (CLT) / Intake (IAT/MAT) Temperature
Sensor Calibration
You can use your stock IAT and CLT sensors, and with the MegaSquirt-II you can calibrate these
sensors through MegaTune. It's best to leave the standard R4 and R7
'Bias Resistors' in place in the MegaSquirt and just configure this in the
software. You get better accuracy this way.
- Open MegaTune>Tools>Calibrate Thermistor
Tables
- Select 'Coolant Temp Sensor', Select
'Fahrenheit', and enter these values:

- Click OK and the Coolant sensor will be
calibrated.
- You're not quite finished yet though--- You
need to repeat these steps, but choose 'Air Temperature' as the sensor
table and use the same temp and resistance values from above as the
sensors use the same curve. This will calibrate the IAT as well.
NOTE-- Make sure you chose Fahrenheit or your
readings will be WAY off with the above values....

More Information
- Everyone should thoroughly read the
MegaManual. I mean... you wouldn't buy a new doo-dad and install
it without using the manual would you? OK now seriously though...
this is your pride and joy we're talking about here... read the
manual and the FAQ!!! www.megasquirt.info
- Read both the MS1 and MS2 sections, not
all of the MS1 section will apply to you, but MUCH of it will, and
the MS2 section isn't really complete without this information.
- Another great resource I refer to often is the
MegaTune Tuning Software Manual-- here's the link: http://www.megasquirt.info/megatune.htm
You shouldn't really 'need' this information, but
it's linked here for further reading if you're interested.
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96-98 4.6l Mustangs
Used two 4-tower coil packs, had a 36-1 wheel but no EDIS module.
Best route on these
to use the existing 36-1 wheel and VR sensor and add an EDIS-8 module. These
vehicles come with stock Motorcraft 4-tower coilpacks that are the same units as
used with earlier EDIS systems – i.e., you only need the EDIS module on these
cars to make them work. NOTE: You definitely want to run genuine Motorcraft
coilpacks, or MSD units as we have seen problems (with forced induction or
nitrous motors) with “Niehoff” or “Wells” (or any other non-OEM or non-MSD)
units.
These cars also had
the “return” type fuel system standard to most EFI vehicles.
99-2004 'Modular' 4.6l
mustangs
99+ 4.6 engines (all
models) use Coil-On-Plug ignition. They run a 36-1 crank trigger wheel
and VR sensor on the crankshaft inside the front engine cover. This is the same
trigger wheel and sensor used for the Ford EDIS system, Ford has just modified
the system to integrate the ignition module inside the EEC and run COPs instead
of a coil pack or two. So you’ve got two options here. Either way you’re using
the existing 36-1 trigger wheel and VR sensor, no need to change anything there.
You’ll want to add an EDIS-8 module though since we’re no longer using the EEC
and it’s integrated ignition module. The VR sensor will now need to be wired to
the EDIS-8 module.
Now's when it comes to decision time:
1) You can use the standard EDIS-8 coil packs and run plug wires. This
is the simplest option for sure and plenty adequate for most installations as
it's basically the same setup Ford used on the 96-98 Mustang. They just
had the EDIS module built into the EEC.
OR
2) Based on the following info from Scott Clark (DieselGeek) you can run COPs
from the EDIS-8 module:
You CAN run the
factory COPs with an EDIS module, although this will draw roughly double the
average power from your COP power supply. There are many successful
reports of this being “no problem” on COP installs, some 03 Cobra’s have made
upwards of 775whp using this scheme. Here’s how to wire an EDIS module to
COPs:
Channel 1 Trigger (EDIS Pin 8) -> Coil 6 (-)
Channel 2 Trigger (EDIS Pin 9) -> Coil 5 (-)
Channel 3 Trigger (EDIS Pin 11) -> Coil 4 (-)
Channel 4 Trigger (EDIS Pin 12) -> Coil 2 (-)
Coil 6 (+) -> Coil 1 (-)
Coil 5 (+) -> Coil 3 (-)
Coil 4 (+) -> Coil 7 (-)
Coil 2 (+) -> Coil 8 (-)
+12v -> Coil 1 (+)
+12v -> Coil 3 (+)
+12v -> Coil 7 (+)
+12v -> Coil 8 (+)
Either way you go, coil packs or COPs, once you've got this wired up and even
without the MegaSquirt hooked up to the ignition system the car should fire
right up (of course something has to be firing the injectors, either the EEC or
the MegaSquirt). This is because the EDIS-8 Module will run the car at 10
degrees BTDC when there is no computer control. This is it’s ‘limp home mode’
base timing.
Note: these years of
Mustangs use “returnless” fuel systems. Dieselgeek prefers to replace the
returnless system with a return-style system, as we’ve seen pressure
fluctuations on higher powered cars running returnless fuel supplies. However,
many cars are running 700+whp with their returnless systems successfully.
Retrofitting a return-style fuel supply is not too difficult on a later model
mustang… most run a new -8 line for the feed, and convert the old
returnless-feed line to be the new fuel return to the tank. Run a Walbro or
similar in-tank pump (or whatever matches your power demands).
Other non-year
specific Mustang notes from Dieselgeek:
Ground the Ford TPS
(ground wire) to the block or chassis. Don’t use the factory temp sensors
UNLESS you “re-ground” them – Ford’s sensors are on an isolated “ground” that
may behave “flaky” causing intermittent, one-second blips in whichever sensors
are on this isolated ground. What I usually do is reground the TPS sensor
ground to the chassis, then share the TPS signal (0-5v) wire going to the
factory ECU with the MegaSquirt. Then I like to run separate GM temp sensors –
the GM CLT sensor threads DIRECTLY into the Ford CLT sensor location, and you
can remove the Ford CLT sensor entirely (factory computer will know it’s
disconnected but will run the IAC fine). Thread the GM IAT into your intake
elbow or anywhere just before the throttle body on the intake.
You NEED the EEC-V
(factory computer) to run the gauges, cruise control, odometer, PATS, etc. It’s
nice to let the factory computer still control the Idle Air Control motor, while
MegaSquirt controls the fuel and spark. Many cars are tested and running
happily this way.
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