Where does the main wiring loom, that feeds the ECU, get it's earth from?

I have a poor earth issue at ECU as some sensors are reading oddly, fixed by earthing ECU case. But suggests I have poor earth where loom picks up earth.


I have already added wide gauge earth wires from battery to strut turrets, manifold, alternator, original shell and engine block earths and one to the OEM ecu mounting cradle.

Thanks

BTT for any info?

Symptoms - MAF signal drops to 0v for fractions of a second, intermittently;
dash temp gauge needle drops to cold and recovers back to normal, when hot ( looks as though ignition turned off and needle drops to rest, but recovers in 3 - 5 seconds, may bounce up and down a bit under middle warm position ). PFC Hand commander shows temp stable.

Looks like loss of signal to ECU or earth/power to sensors?

Not likely to be PFC fault?

I've now added extra earth to the loom earth points behind each strut top and cleaned the plug on the loom at o/s rear bulkhead, and the earth on the starter motor. Runs smoother on MAF signal now, but intermittent drops signal. May be MAF is dodgy, ordered a new one now to eliminate the possibility.

New Z32 MAF fixed the MAF / runningproblem, but watre temp gauge still drops when revs pass 3500 !

Would this be a poor earth to dash gauges, would it affect anything else ( fuel gauge? ) and how would I cure that?

Thanks