Key is OFF but all of the injector connectors except one ...

Hello again and thank you for the request. No, that is not normal. The injectors should not draw anything with the key off. Make sure that there is no power reaching the injectors with the key off and that the ground wire has no continuity to ground. If you do have that with the key off we are either dealing with damage to the harness or that ECM is bad like I suspected at first.

I see. Yes both cases are possible. ECM could cause all sort of issues. I understand that. I'm going after the harness first. So let's say the ECM is working fine. Here's what troubles me. When key is ON, I have around 6 volts on all injector connectors except that single connector which reads 8.8 volts. How would a harness damage explain this?

Corrosión or pinched wires adding resistance.

It may seem simple to you but I have a hard time understanding it. If there's corrosion or pinched wire somewhere, I'd expect one or two show out of line numbers but what I have is all of them seem faulty except one. I know it's possible but hard to imagine all of the cables are bad except one. Am I missing something?

yeah it’s very strange the way your issues are coming up but there’s nothing else that I can think of to explain your symptoms.

Totally understand it. One more question, when car is off, what makes the voltage to reach to the injector connectors beside a bad ECM?

the ECM does not provide voltage. when the ignition switch is in the on or running position power is fed to the injectors via the fuse box

Sure, I asked cause you said Make sure that there is no power reaching the injectors with the key off. I was wondering what to check for that.

you’d just check at the injectors. to be drank seems that you have some deep electrical problems going on and it’ll take some time and various tests to narrow it down.

Got it

let me know what we find out.

Well, you say Make sure that there is no power reaching the injectors with the key off and that the ground wire has no continuity to ground. Power reaching the injectors is through checking at the injectors as you said. That's the input that I gave you meaning I've already checked on that and power IS reaching the injectors. Ground wire continuity to ground is another one. I'll do my best on that. Thanks

yeah no problem.