MSefi.com read only forum (Jan.15,2018)

I am doing a ms2 b&g 2.92 fuel only. In early documentation the tps ground just went to ground. Later documentation has tps ground to pin 19 to help with noise. In my case the tps is shared with the factory gm pcm which all the gm grounds ground to a stud on the intake. Rather than physically solder on the gm ground to MS pin 19 I would like to just run the pin 19 ground to the stud on the intake. All the other MS grounds will ground to that stud. Does anyone see a problem with that

The general rule is *all* sensor grounds go to a ground pin on the MS DB37 connector. And MS is grounded to the block via other pins on the DB37.

If you unplug MS, no sensor should have a ground.

The theory is if you ground a sensor to the block, it will share a high current ground which may well have some 'spikes' on it. The sensor inputs are required to measure tiny currents, and these spikes can interfere with that and give false readings.

I will separate them but I expect it is my limited understanding of grounds. When the grounds get to the MS pins 7 through 19 are all common and that is the part that has me not understanding why they should be separated. I am not questioning I am just trying to understand.

The fellows over on the Extra forum have a pretty diagram that explains why certain grounding arrangements are bad; it has to do with the current flow through the main ground wires causing a voltage offset. By grounding the various sensors directly (and exclusively) to the MS, the trivial current flow means no voltage drop and no sensor reading errors. Also - as you noted - noise can get pretty crazy on the heavy ground wires.

Thanks, I think I getting now.