So...I bought a pre-assembled DIYPNP for my 1990 1.6 probably a decade ago, when I installed it I (believe) I forgot the ST SIG fuse, and fried the high side driver. No fuel pump. No start. I jumped the F/P and GND in the diagnostic box as a "temp fix" and have been driving it that way until this day.

After all these years I finally decided to open up the Megasquirt and replace the high side driver, and to my surprise I opened it up and I do not have one?! 😵 I just want my fuel pump to not be constantly running when the ignition is on, and the drivability of the car not relying on a paperclip in my diagnostic box haha

So my question is...what next? Do I install a tip125 transistor (as pictured below)? Or will that create a host of new issues? (I did not build this so I'm a little out of my element, however I have been practicing my soldering ha) Any help is appreciated, thank you!

 

The fuel pump relay can be activated by two ways: One is with a high-side output that can be done through the stock wiring; the other is with a low side output (ie the one that is already built into the microsquirt module) but you will have to run an extra wire from the DIYPNP to the fuel pump relay OR to the AFM plug (as that is what is triggering the low side relay once the car starts). I would choose the second option.

 

Thank you for your help, the second option sounds feasible! Any chance you could walk me through exactly what I need to do?