Ecu Grounding Q's??
 

Has anyone tried regrounding the ecu and benefited from doing so?

yes, it eliminates the chance of a bad ground or broken wire, and the car miss reading the sensors.

I would recommend it to any car over 10 years. You should re-ground the engine an battery at the same time (although I always upgrade my battery to ground and engine to ground, even on brand new cars).

Yes well this is an interesting topic.Getting a good ground to the ecu is obviously important.The ground to the ecu is made from a couple of wires in the engine harness which are grounded to the engine block under a bracket which supports the vacuum lines on the drivers side of the motor.So anything to improve this path could help.
However there is an equally important grounding arrangement which is often overlooked.All the sensors are grounded FROM the ecu in a loop arrangement which is in the engine harness.This ground loop has mechanical joints which deteriorate with time.If you have this kind of problem,the ONLY solution is either repair the harness or add ground wires to the affected sensor.

I grounded my ECU to try and eliminate the 3800RPM hesitation on my 86 GXL, but it had absolutely NO effect. However, I've since tried 3 different ECU's in there [all from '86 GXL standard], and two of the three worked perfectly, but one of them had the same hesitation problem as mine did! If you're trying to fix the hesitation problem, my suggestion is getting a new ECU.

I've seen a lot of posts recommending grounding the ECU, battery, and engine. I have a '87 TII. Where are the recommended ground points for each when adding ground straps? Are any of these grounds isolated from the others, or can they all be grounded at the same point?

Just replacing the existing grounds with 8 awg wires will generally fix many of the problems

Where on the ECU would one add a ground, if one were so inclined to do so?

I had that absolutely HORRIBLE hesitation that was intermittent in how bad it was but it was always there. I have 3 rx7's, 1 a parts bitch, the other i wrecked but has a strong ass engine, and the third my baby with a bodykit that has the hesitation. I tried ground the pressure sensor to no avail. I also yanked the ECU out of both the other cars and tried them to no avail. I hooked a voltmeter up to the wires that carry the power for the injectors, all were giving me basically ok readings. I replaced the cats which i ended up gutting. It was driving me insane but there was nothing i could do. Then i read on some stupid little website that the grounds from the injectors could be a possible cause and since i was running out of options and ideas i said what the hell i did it. VIOLA!!! it was gone and i had a so much smoother power curve which was great. even if your car isnt hesitating ground the ECU cause Mazda RX-7's have got to have the record the THE WORST grounding job of any car ever built. well thats my 2 cents, hope it helps you out.

88SE
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K&N Filter
Gutted Cats W/Stock mufflers & Y pipe
Body Kit W/New paintjob
Clean inside and out

Actually no, Mazda has pretty good grounds, compaired to many japanese cars. If you think Mazda grounds are bad you should see some of the early to mid eighties Hondas and Nissans I have seen. Saw this 86 Prelude once that lost most of the engine ground and when the girl cranked the car, the whole harness smoked like a fuse in a bugs bunny cartoon.

Any car more than 10 years old is gonna have electrical problems. Even my Lexus, if you look at the Lexus forums/boards, people have the same exact problems with grounding on the older cars that we do.