I have located the two pins that go back to the fuel pump driver out back. One seems to light up 12v briefly at key on and the other I assume is being PWM'd as it seems to have only a few volts with a quick spot check on the dmm.
Anyone know how the PNP ecu accomplishes this? Is there a specific 12v hot/pwm grounded circuit that uses the factory fuel pump driver?
The car is a 2002 bugeye wrx with an EZ30D/SEx-257/6speed. The stock ecu is still in the car for obd2 purposes, but currently without rpm signal from a 4cyl I only get a brief view of the factory behavior.
WRx fuel pump driver circuit
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Re: WRx fuel pump driver circuit
There is an enable signal that puts out 12 volts at all times the fuel pump is on, controlled by the standard fuel pump output. Then there is a 5V PWM signal that is triggered by an AND logic between the fuel pump output and PWM3 to control the fuel pump speed.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
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Re: WRx fuel pump driver circuit
Thanks Matt,
Is the "and" function done within programming or is it run thru a logic gate?
Is the "and" function done within programming or is it run thru a logic gate?
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Re: WRx fuel pump driver circuit
Just thinking out loud here, but could I use the std fuel pump output to throw 12v at the one leg via relay or transistor, and say Spark H to PWM 5v to the other leg? Seems like a win/win in simplicity
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Re: WRx fuel pump driver circuit
Success! So I just mapped Spark H to the 5V TTl line ( Violet with white stripe, pin 15 on connector B136) and it works without sending 12v to the other line.
Now I just need to work on exporting a 4cyl 36-2-2-2 signal to the stock ecu from the megasquirt and I'll have the groundwork for a PNP harness to allow the masses to swap the 6cyl into a WRX and keep emissions devices intact
Now I just need to work on exporting a 4cyl 36-2-2-2 signal to the stock ecu from the megasquirt and I'll have the groundwork for a PNP harness to allow the masses to swap the 6cyl into a WRX and keep emissions devices intact
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Re: WRx fuel pump driver circuit
Logic gate.BaldTurboFreak wrote:Thanks Matt,
Is the "and" function done within programming or is it run thru a logic gate?
Matt Cramer -1966 Dodge Dart slant six running on MS3X