Ignition Grounding Issue

[MR2K24]

Hello,

I have a k24a2 swapped mr2 spyder running kpro v4, and I have been having an issue with the ECU not grounding the EFI main relay. I have tested the coil side of the relay and I am getting 12v. I traced back the ground wire to make sure it went to the ecu and it is for sure connected to pin E7. The relay will not trigger when I turn the key.

I have tested the relay and It works great, I have also swapped relays to make sure that wasn't the problem.

Have you ever seen this issue with the ECU's?

I also have a p0563 VBU high voltage code, which I have read is because the main relay is wired incorrectly. Would this have any effect on the E7 pin not grounding?

Thanks guys!

[Hondata]

Yes, this is a very common problem with engine swaps. If the ECU is wired to the main relay incorrectly, even once briefly, then it will burn out the ECU main relay ground circuit. This gives the problems as you have described, including the VBU high voltage.
If possible test the ECU in a known good vehicle and see if it works there. Check your main relay wiring, but be aware the ECU may have been damaged before you used it.

[MR2K24]

That's what I figured. Thank you for your response.

I have a couple more questions.

If I just wire that relay as a kill/manual switch, would hondata be fine running with the VBU code?

Is there a way to replace the ECU main ground relay or will I need a whole new board?

Are there other pins other than E1-E7 that would short the ECU if a 12v was fed to them incorrectly?

[Hondata]

Yes, you can bypass the main relay output and the ECU will run ok.

It is hard to tell what might be damaged on the ECU but the first step would be to test the ECU in a known good vehicle to isolate the problem.

The fuel pump relay output is often mis-wired and damaged in the same was as the main relay output.

[MR2K24]

Great, thank you for your help!