Dual Point to Multi Point Fuel Injection

     If you have a Dpfi car this is the most important performance upgrade you can do to your car. The gains will be around 8-12 hp. Bolt ons will actually benefit your car to. With the dual point intake there really isn't anything you can do to your car to gain any real hp.
Parts Needed
  • 88-91 Si intake manifold including throttle body, fuelrail, and injectors
  • intake manifold bracket
  • intake manifold gasket
  • ECU: pm6, pr4, or pm7
  • 88-91 Si resistor box
  • 88-91 Si distributor
  • 88-91 Si fuel line from filter to rail
  • stock engine harness
  • injector plugs
  • intake tubing
  • extra wire
  • plug with atleast 4 wires
     The wiring being done is very simple. To someone who is new to working on cars or wiring this can seem like a huge undergoing but it is actually very easy. To those who are weary of doing this or don't understand it, take your time and read through it a couple times until you understand what you will be doing here. you will be doing the wiring for the injectors, crank angle sensor, throttle position sensor (tps), and lengthening some wires. So, get your mpfi manifold on and lets get onto the wiring.
     The TPS is on the throttle body on the opposite side of the trottle cable. The EACV is on the back of the intake manifold.You are going to need to extend the TPS and EACV wires. Extend the throttle position sensor about 8" and the EACV about 5". While extending the the tps switch the green/white and yellow/white wires. If you don't switch the wires the computer will think the throttle is in the opposite position it is actually in.

MPFI Crank Angle Sensor
     Pins B10 and B12 are empty. The wires from C1 and C2 need to be moved there. So cut C1 and C2 off but leave some wire because you will use these. Run The wire you cut off at C1 which is orange to B10 and the wire you cut off at C2 which is white to B12. Now run the ecu side wires from C1 and C2 into the engine compartment. It would be smart to use a plug or something just incase you need to disconnect wires.

     Next is the distributor and crank angle sensor. On the Si motor the distributor has 7 wires and the Dx or Std have 5. This is because the Mpfi motors have a crank angle sensor. What you'll need to do is cut the rectangle distributor plug off of your DX harness. Then you'll take the circle mpfi distributor plug and solder it to your DX harness. Just match the wire colors up. There are 2 white wires but one is larger than the other. Now plug the distributor plugs together. There will be 2 wires left coming out of the distributor, a blue/green and a blue/yellow. These are for the crank angle sensor. Blue/green go's to C1 and blue/yellow go's to C2.

Injector Wiring
-Looking at the injector plugs you got off the mpfi harness you'll see each plug has a red/blk wire and another colored wire. Run all 4 blk/red wires to the resistor box.
-Looking at the 2 injector plugs on the Dx harness you'll see eack plug has a yel/blk wire and another colored wire. Run both yel/blk wires to the yel/blk wire at the risistor box.
-Injector plug # 1 has a brown wire left. Run this to the yellow wire connected to the Dx injector plug.
-Injector plug # 3 has a blue wire left. Run this to the red wire connected to the other Dx injector plug.
-Before wiring injectors 2 and 4 go to the ecu. Cut the wires located at A3 and A7. A3 is yellow and A7 is red. Run these into the engine compartment.
-Injector plug # 2 has a red wire left. Run this to the yellow wire you ran from A3 into the engine compartment.
-Injector plug # 4 has a yellow wire left. Run this to the red wire you ran from A7 into the engine compartment.

PM5/PM9 DPFI & PM6 MPFI ECU Pinout Comparison

Pin NumberNon-OBD PM6 ECUColorsNon-OBD PM5 ECUColors
A1#1 InjectorbrnAux Injectoryel
A3#2 InjectorredAux Injectoryel
A5#3 Injectorlt bluMain Injectorred
A6Purge Cut-Off Solenoid ValvegrnPurge Cut-Off Solenoid Valvegrn
A7#4 InjectoryelMain Injectorred
A8Lock-up Control Solenoid ValveyelLock-up Control Solenoid Valveyel
A9- -
A10Shift Lock Solenoid Valvewht/redEgr Control Valve (CA Only)red
A12Main Relaygrn/blkMain Relaygrn/blk
A13Main Relayyel/blkMain Relayyel/blk
A14Main Relaygrn/blkMain Relaygrn/blk
A15Main Relayyel/blkMain Relayyel/blk
A17- -
B1Ignition Switchwht/grnIgnition Switchwht/grn
B2Fast Idle Air Control ValvebluTandem Control Solenoid Valveorn
B3A/C Clutch RelayyelA/C Clutch Relayyel
B4Radiator Fan Relayyel/grnRadiator Fan Relayyel/grn
B7P/N InputgrnP/N Inputgrn
B8A/C Switchblu/redA/C Switchblu/red
B9- -
B10Crank Angle Sensororn-
B11D4 Inputgrn/blkD4 Inputgrn/blk
B12Crank Angle Sensorwht-
B13Ignition Switchblu/whtIgnition Switchblu/wht
B16Speed Sensoryel/redSpeed Sensoryel/red
B18- -
B20Ignition Timing Adjusting ConnectorbrnIgnition Timing Adjusting Connectorbrn
C1Cylinder Position Sensorblu/grnCrank Angle Sensororn
C2Cylinder Position Sensorblu/yelCrank Angle Sensorwht
C3TDC Sensororn/bluTDC Sensororn/blu
C4TDC Sensorwht/bluTDC Sensorwht/blu
C5TA Sensorred/yelTA Sensorred/yel
C6TW Sensorred/whtTW Sensorred/wht
C8- EGR Valve Lift Sensoryel
C9PA Sensorred/whtPA Sensorred/wht
C10Brake Switchgrn/whtBrake Switchgrn/wht
C11MAP SensorwhtMAP Sensorwht
C12Sensor Groundgrn/whtSensor Groundgrn/wht
C13Reference Voltageyel/whtReference Voltageyel/wht
C14MAP Sensorgrn/whtMAP Sensorgrn/wht
C15MAP Sensoryel/redMAP Sensoryel/red
C16O2 Sensor AwhtO2 Sensor Awht