This post may not be related to tuning but more towards wiring problem but I am hoping that I could get some basic guidelines as I consider myself still new in the arena and still got a lot to learn
I am currently using Link G4+ Monsoon on a 3SGTE ST246 engine on my Toyota MR2. Car was running great for the past few months until recently I could not get my car to start. After I did the basic check-up I found that the fuel pressure is '0'. Therefore my focus would definitely be the fuel pump. For your information, the wiring was not done by me but I am now learning to do such wiring myself.
My fuel pump is activated from a relay that uses AUX 6 of the Link G4+ Monsoon. I try to run the test using PC Link and can hear the sound of the relay clicking but I don't hear the priming sound from the fuel pump. Then I try to directly run the fuel pump from the battery (12v current) to its connector and I can hear the fuel pump priming. For that, I concur that my fuel pump is working and is not the fuel pump issue itself.
Next from the connector that I have disconnected from the fuel pump, I tested it with a multimeter. What I found that there is a current supply of 8v-9v to the fuel pump when the key is ON (after finish the 2-second priming that I have set at Link G4+). When I set at PC Link Software 'test ON' for AUX 6 which is the pump, the current supply becomes 2.8v-3v along with the clicking sound. Picture attached is as per my explanation.
Picture #1 8v-9v before TEST ON fuel pump at PC Link
Picture #2 2.8v-3v during TEST ON fuel pump at PC Link
Next, I try to test all the fuses that I can have my hands on but all the fuse seem okay. As my logic and understanding of wiring, I don't feel its the fuse as there are still current flows to the pump but it just seems that the current is low for the pump to operate. As I mentioned above the wiring was not done by me, therefore, I try my best to detect the wiring with the limited knowledge that I have.
I seek the advice here to guide me on how could i further diagnose and solve this issue myself. Your advice and guidance is very much appreciated.