xEtherealx

I'm reworking a truck harness and the ECM has 8 grounds coming from it, which sometimes combine in splice packs and tie into the sensors. Am I ok to combine all the sensor and ECM grounds, making a connection to the block with one ground lug in order to clean up the wiring?

EFIHARNESS

Sensor grounds are not chassis grounds. you can tie all the sensor grounds together
and go to 1 low ref.
The chassis grounds need to go to both heads and block as the coil packs are not always grounded thru the valve cover. Steve

xEtherealx

That makes sense, my sensors' grounds all go directly to the ECM while the 8 ECM chassis grounds all ended up at splice packs. After noticing that there are less grounds going into the splice packs than leaving to the PCM it's obvious that their only purpose is to tie into the ground lug connecting the grounds to the engine. Thanks!