Mitsubishi Magna Distributor
Used pigtails have the same problem with corrosion as do the injector clips on C/S cars. You can replace those terminals inside that used connector with new terminals and they are readily available. You need two new clips and pull the wires from them, after you've added in the resistor to provide the pull-up signal to the MSII ecu reinsert them into the clip. You don't need the 4th wire. This is a new injector clip and one of the terminal removal tools you can purchase. If you don't have or want to buy that tool, grind down and old screwdriver, its just a thin metal strip but some screwdrivers went ground down with be soft and hard to pry the locking tabs out.
You can see this terminal is corroded and shouldn't be used or washed, it is trash. That is compared to the new terminal after it is removed from the injector clip.
This is the resistor added between the 12V (+) feed to the distributor from the ignition switch and the sensor output that goes back to the ECU. This pulls up the voltage to 5V. It is a 2 Watt, 1K ohm resistor. All you do is jumper those two wires. The 3rd wire is a ground.
Insert the new terminals into the Magna dist. connector then insulate the legs off the resistor.
This is a test harness made to verify that the two sensors are working and to show the signal they produce.
You'll need a fully charged battery, two 390ohm resistors and 2 leds.
Why test both sensors when you only need one? If you plan on later adding in the Router Board to control sequential injection and/or coil-on-plugs you will need this 2nd sensor to have distributor-less ignition. The distributor will function fully as your cam/crank angle sensor. http://www.megamanual.com/router/index.htm shows you how that works. To make the test harness all you need is a 390ohm resistor and an LED. Its shown on the Megasquirt site how to do this as well. The resistor is wired into the LED to keep is from burning out. When power is applied to the test harness both LEDs should illuminate when the distributor isn't plugged in. When you do plug it in it will depend on the position of the rotor if both or either of the LEDs are on or not. You'll need a fully charged battery, this one almost is and if not your readings will vary accordingly. Added into the harness are three (one missing the tip) probes to touch to the volt meter: the ground, the lead for the red banded LED and one for the white banded LED.
As you rotate the drive gear on the distributor you'll observe the LEDs flashing. You'll have the white banded LED "on" when the rotor is at the number one plug wire position and that is when the rotor points directly at the electrical connector and this is what Megasquirt uses for a signal. That signal is used for the high current ignition driver and there are 4 pulses per turn of the rotor the same as if you had an old style points distributor when the rotor is at 12,3,6 & 9 o'clock positions. The 2nd sensor is tied to the red banded LED and it is only "on" at TDC and can be used as the crank angle sensor portion. These two sensors sending out the 5V pulse in squarewave form makes this distributor excellent for use with MSII.
This is a short .avi file testing the distributor. It shows you the pulses generated from the sensors with the test harness connected to the distributor and to a battery while the drive gear was rotated by hand.
right click save or just mouse over and it will play
Continuing on with wiring the MSII harness to connect to the distributor. This is the sensor wire back to the ECU. The shielding can't be allowed to contact the sensor wire, pull the shield back and keep it separated. This is shrink wrap to hold it folded back.
These tiny gauge wire, 18-20ga I crimp twice, just squeeze and slide over and squeeze again. It takes but 2 seconds to crimp these terminals. The bare wire is coated with the coating mentioned at the top of the page then the shrink wrap slid over the connector to insulate it. Remember to put the shrink wraps all on first including the larger pieces depending on how you want your harness to look.
There is friction tape after the wires come from the connector were covered and before the harness wrapping. This makes the transition between those two diameters even. The blue band is part of the wiring diagram coding.
MSII and Megatune might not allow the motor to start up easily with the drive gear in the position you will have when you get this distributor. While you can move the trigger offset to get the engine to run Megatune is using the trigger offset for cranking and MSII is receiving a signal to fire the plug based on this offset. The crank degrees the dist. can use for either rising or trailing edge of the signal is ~70 then a period of ~110 degrees before the next cycle then it repeats. Unfortunately you can't have it both ways, you either get good startup or good running -if you have the offset say about 20-25 or -30 depending on which tooth you are using when you insert the dist. into the head that won't allow the motor to start up without kicking back on the starter. This could break the start drive. This isn't likely a problem on all intake manifolds but on this one we weren't allowed but a small percentage of the adjustment range.
You should make sure the person doing the modification to your intake manifold knows what dist. if any you are using and move the thermostat housing up and\or back further than it is on this one so you can get the full adjustment range. If you are using a stock C/S distributor this might not pose a problem but this Magna dist. is must larger in diameter so make this known.
Something had to be changed: the stud in the head, the slot in the dist. body, the t-stat housing on the manifold or move the dist. drive gear. On this unit, its aftermarket by the way, there were 4 holes instead of the usual 2 on a C/S dist. There are 12 teeth so of the 720 degrees of crank angle (2 turns crank=1 turn cam) one tooth is 70 degrees. We had an adj. range of about 20 crank degrees. This put the initial timing too far off. Easiest solution was to drive the pin out and rotate the gear 180 degrees (half turn) and put the pin back in. You can see this is before the gear was repositioned. On one side the holes are in the bottom of a tooth and the opposite side it is at the top. (there were two sets holes in this gear I don't think the factory units are like this)
Now reinsert the dist. and using the test harness if you made one you'll get the rising edge of the signal that you'll use just about 6.5 degrees BTDC and this will be the "initial timing". If you don't have or didn't make a test harness you will see the rotor position just to the side of the terminal connector when the timing mark on the crank pulley is at about 6.5 degrees BTDC.
Set your trigger offset in Megatune so these numbers match, then fill in the advance tables after you get the dist. calibrated.
You'll have the dist. body fully at one end of the adjustment then lock it down.
How do you use this signal? Pick the rising or falling edge in Megatune. We are only using the ignition signal. Ignition options in Megatune: for Ignition capture use falling edge and for cranking use rising edge. If you pick the rising edge for ign. capture you end up having ignition advance and the rotor isn't even near the plug wire this is why to use the falling edge. For cranking, since we ended up with ~7 degrees btdc when that occurs we use the rising edge. The initial adv. for the most part = trigger offet and trigger offset is called the adv. offset in their code. You'll see those 3 terms used so remember they are talking about the same thing each time in different places. The total adv. your engine will ever see is (=) the trigger offset + your spark adv. table numbers + your cold adv. table. After the engine starts you can set the trigger offset to calibrate the dist. with a timing light but remember your maximum adv. when you set all this up. As you rotate the dist. body the rotor isn't moving and the sensor is part of the body not the rotor. You don't want the window of max. adv. to be out of range of where the rotor position is in relationship to the plug wire.
The 0 point on the wheel is at the center of the rotor. Note the LED, white band is ignition, red is TDC
TDC sensor & ignition hall sensors are separate
TDC signal for ~70 degrees=140 crank degrees
Ignition signal for ~30 degrees=70 crank degrees (also equal to one tooth on the dist. drive gear)
TDC begin Ignition begin Ignition end TDC end
