I gather if it was grounded properly it should be okay. The mounting nuts for the ECU are good for regrounding purposes.

 

Now I'm a bit clueless what to do next. I'm going to check the grounding stuff again tomorrow but I guess there are no more faults.

 

I just checked the grounding again and couldn't find anything wrong. Maybe my secondary injectors really need a cleaning. Those hesitations feel exactly like the 3800rpm hesitation but they don't have a specific point where they appear. The only requirement is that the secondary injectors must be running.

By the way what exactly happens at the 3800rpm hesitation? Are the secondary injectors injecting too late?

 

They don't receive the trigger signal, which is a ground, from the ECU. Did you ever add additional grounds to the existing grounds or just clean up the existing ones? If you only cleaned up the originals then you might want to reground by adding some.

If you measured the voltage on the Light Green wires specific to the secondaries ( LG/W front sec. and LG/R rear sec.) then you could tell if they were being sent the ground trigger as the voltage on these two wires would drop to about 8 volts or so from 12 volts when the 3800 rpm level was reached.