1G Fuel Pump Voltage Sensor

[Mokkan]

Where is the fuel pump voltage sensor located on a 1990 GSX? I've checked the factory service manual electrical diagrams and don't see it anywhere.

I had 6.1v at the pump, so I ran my own 10 gauge wire from the MPI relay output to the pump input, since the wiring diagram showed nothing except for the pump check port between the two. The pump now has 12v, but the check engine light is on and is indicating a fuel pump issue. I'm assuming I bypassed the voltage sensor with my rewire and I would like to put 12v back to the sensor so it will turn the CEL off.

 

[steve]

Where is the fuel pump voltage sensor located on a 1990 GSX? I've checked the factory service manual electrical diagrams and don't see it anywhere.

That's because there is no such thing. The closest thing is the sense input on ECU pin 13. The output from the MPI relay runs to the pump and the ECU pin.

The connection is documented in the 1G DSM Technical Manual and the real 1990 FSM but was dropped from some later versions of the FSM including the ones scanned for the backupCD manual.

I suspect you didn't connect ECU pin 13 to the replacement wire and your now getting a 44 fault code since the ECU can't tell that there is power when it things the fuel pump should be on.

 

[Mokkan]

Awesome! Thanks for the explanation. I can run a jumper over to pin 13 easily enough - and now that I see it, I realize I must have overlooked that pin in the dsmlink ecu pinout. I have a hardcopy 1990 manual coming in the mail now, which I should have done before rebuilding the engine and messing with wiring.

 

[Darksurfr]

Hey guys. Having a problem that this seems to be linked to. Does anyone have an image of what pin 13 goes to? I am trying to wire my flash ecu but needing pin 13 hooked up to something i think and pin 56. 1990 FWD TSI. or GST for ease

It seems like there is 12 volts on pin 13 when the car is running but not sure whatt he purpose of pin 13 is when pin 56 seems to be what the FSM shows is the equivalent of pin 8 on the 98-99 ecu. Little lost right now. sorry to bring up an old thread and change the topic but Really trying to figure this out and I have no access to post in the flashecu threads.