Jeffersonc Posted July 27, 2018 Report Share Posted July 27, 2018 Wiring my first ECU into a racecar I recently bought. Custom chassis and engine harness. I am getting electricity back feeding out from the +14 pin on the ECU. It starts once I turn on the main power safety switch to the vehicle. The engine is an RB25 in a 240sx chassis. The only way I can get it to stop back feeding is by unplugging the VCT plug at the solenoid. I have tried another solenoid for testing purposes but it continues to back feed. If I unplug the solenoid and install a light bulb, the back feeding stops. The VCT, CAS and Injector harness +12 power wires are grouped together and supplied from a fuse circuit from the custom fuse box. The coil harness +12 power is on a separate circuit as I was told to wire it this way. Any ideas where to start? The VCT is wired into AUX Output 2. Quote Link to comment Share on other sites More sharing options...
Jeffersonc Posted July 27, 2018 Author Report Share Posted July 27, 2018 Fixed! the power circuit for the VCT, CAS and INJ was actually on a constant power supply. Well, a power supply that is hot when the vehicle safety switch is turned on. (it was considered the "dome light" circuit according to the fuse block manual I found) For a test I used an IGN switched power source and it's fixed. Now question. Should the +14 power supply for the ECU have a fuse? It's currently a direct feed right off the IGN switch on the dash. Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 27, 2018 Report Share Posted July 27, 2018 22 minutes ago, Jeffersonc said: Now question. Should the +14 power supply for the ECU have a fuse? Its currently a direct feed right off the IGN switch on the dash. 1 Yes, ideally it would be fused at about 5A. Quote Link to comment Share on other sites More sharing options...
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