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How to MegaSquirt your V6 powered Ford Probe GT or Mazda MX-6 / MX-3Using the stock distributor or wasted sparkUpdated 9/11/2009 - Added MX-3 wire colors
Application(s): This article covers the 1993-1997 Ford Probe GT, Mazda MX-6, and Mazda 626 equipped with the KL-DE, KL-03, or KL-ZE engines (2.5 liter V6), with a manual tranmsission, as well as the '92-94 MX-3 with the 1.8 V6. See notes about automatic transmissions under "Other Things the ECU Controls." The first generation Probe LX used a 3.0 pushrod V6 with electronics very similar to the 5.0 Mustang, and can be MegaSquirted using the same mods as in our Mustang article. Level of control: Full Standalone EMS-- Fuel and Ignition Control There have been several ways to install MegaSquirt on these engines, but we've worked out a method of using the stock crank trigger wheel and the one tooth wheel in the distributor to get the accuracy of a crank trigger, without having to file any teeth off the pulley or make any other changes to the engine wiring. This works on both OBD-I and OBD-II motors, so if you have a later car, there's no need to swap in an early distributor. ECU ModificationsOn these engines, you can use either the MegaSquirt I or II. We recommend the V3.0 board if building one yourself, or the V3.57 if buying one ready made. In either case, you'll want to use the Extra code.
WiringHere are the wires you'll need to grab for ignition control and where they connect to the MegaSquirt. The crankshaft position sensor is on the front of the block, connected near the temperature sensor. The camshaft position sensor is in the distributor, as is the ignition module. The distributor wiring colors are slightly different depending on the year and model. Probe wire colors (all years):
MX-6 1993-1995 wire colors:
MX-6 1996-1997 wire colors:
MX-3 1992-1994 wire colors:
Be careful not to wire the crankshaft position sensor backwards; this can result in a noisy RPM signal and unsteady timing. Idle Air ControlThese engines use a pulse width modulated (PWM) idle air control motor. A V3.57 board can control this directly. With a V3.0 board, you will need to add our PWM idle control mod kit to control this valve. Other Things the ECU ControlsThe stock ECU controls a couple other devices in these cars besides the injectors, ignition, and IAC valve. Here's what to do about the ones you will need to control. Fuel pump: This is a standard output on the Megasquirt. Wire the Megasquirt pin 37 to the fuel pump relay wire that went to the stock ECU. Air conditioning: While the stock ECU controls the air conditioner, you don't need a computer to make this work. Wiring the A/C request wire running to the ECU to the A/C compressor relay should make this work, although we have not tested this one for ourselves. VRIS: The Variable Resonance Induction System uses two separate solenoids to operate a set of butterflies in the intake manifold to change the intake characteristics. You can leave both open, but it is possible to control them with the MegaSquirt. The factory settings have VRIS valve 1 open at 3250 RPM and valve 2 open at 4250 RPM. You can drive the solenoids from the MegaSquirt using our relay control mod kits. Cooling fans: There are two relays for the cooling fans in these cars, one of which turns on the fan in low speed mode and the other turns on the fan in high speed mode. You can either maintain the two stage mode by using one output to turn the low speed fan on and a second output to turn on the high speed fan at a higher temperature, or simply run the fan off at low temperatures and at high speed when the engine gets hot. Use our relay control mod kits for fan control. For more information about the relay outputs, see our Common MegaSquirt Modifications page. Note that the MS1 has only four such outputs, and using them all will keep you from being able to also run boost control. With the MS2, there are enough general purpose outputs to run all four VRIS and fan outputs and have one left over. Automatic transmission: On OBD-II cars, this is controlled by the ECU directly, so if you have a '96 or later car with an automatic, you'll need to do a parallel installation. (See this link for more information on how to do this.) On '95 and earlier cars, the transmission ahs a separate controller and it looks like this can work without the stock ECU, although we have not confirmed that at this point. Gauges: These are not controlled by the ECU, so if you're using the stock distributor you have nothing to worry about here. MegaTune Configuration for MS2/ExtraSet the following under Tach Input / Ignition Settings.
Dwell settings will depend on the coil used; 2.5 to 3.0 msec is a safe starting point. A typical rule of thumb is to back off the dwell until you can just barely detect a misfire under lean cruising conditions, then add 0.2 ms of dwell time. Use these trigger wheel settings.
If you use someone else's .msq file we do recommend you check the firmware version the .msq file was built on as you cannot always use a file built on one firmware version with an ECU running a different version or a different ignition setup-- it's best to use the .msq files with the same version of the firmware that the file was built on. Alternately you can manually copy the settings over from the borrowed file.
MegaTune Configuration for MS1/ExtraUnder Codebase and Output Functions, set Wheel Decoder to Generic Wheel, and all other code types to Off. Set LED17 (D14) Function to Spark Output A. Do not enable the other spark outputs. Use the following wheel decoder settings:
On the 'Spark' menu choose 'Spark Settings' and set 'Spark Output Inverted' to NO, and set the trigger angle to 60. It is critical to get the Spark Output Inverted setting correct, as setting this wrong can result in damage to the ignition module or coil. Dwell settings will depend on the coil used; 2.5 to 3.0 msec is a safe starting point. A typical rule of thumb is to back off the dwell until you can just barely detect a misfire under lean cruising conditions, then add 0.2 ms of dwell time. If you use someone else's .msq file we do recommend you check the firmware version the .msq file was built on as you cannot always use a file built on one firmware version with an ECU running a different version or a different ignition setup-- it's best to use the .msq files with the same version of the firmware that the file was built on. Alternately you can manually copy the settings over from the borrowed file. Going distributorless?Yes, you can use these input mods for a crank triggered distributorless ignition, with different hardware mods. Software changes are minimal: Just enable spark outputs B and C with MS1/Extra, or set Number of Coils to Wasted Spark in MS2/Extra. You will keep the same ignition input mods, but the output mods will be different, and the stock tach will not work without mods as it is triggered from the ignition module. The mods needed will depend on the coils you're using. For example, these mods will work if using BIP373s to drive a coil without built in ignitors.
Suggested partsOn these motors, you can use a MegaSquirt I or II, although the MegaSquirt-II has the edge. We recommend using a GM open element IAT sensor and removing the air flow meter. ECU options:
Mod kits discussed in this article:
Other recommended parts
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