Analog Grounds....
 

Hi Guys

Having just got my MS2 from Reverent and working through the teething issues I wonder if anyone can help a few newbie questions?

(The tuner studio software is a bit daunting compared to the link S/w I have played with in the past!)

Rev has had a quick look at a log (rough idle and poor throttle tip in/pick up under 3000rpm) and has suggested that the IAT, TPS and something else..maybe CLT? all show signs of noise.

He suggested that I improve the "Analogue Grounds".

I have done a google search and all I can see is issues related to LC1's.

There is a post from Joe in 2010/11 about the Analogue grounds all being in the loom and going back to the ECU....that being the case how do I improve the analogue grounds?

Can I ground the ECU directly better than it is ?

basically meaning you'd run all your sensor grounds directly to the MS.

https://www.miataturbo.net/attachmen...ine=1377868985

https://www.miataturbo.net/attachmen...ine=1377868985

Thanks Scott, now I want to rewire my car.

blame mazda for connecting the black/lt. green wires to the chassis grounds.

Those images really opened my eyes when I first saw them.

Shitty grounds and general Mazda wiring harness douchebaggery has lead me to just building a completely custom harness.

Great diagram. Who made it?

Thanks guys. that is REALLY helpfull.

I will arrange that wiring as recommended.

A quick question, one of the issues that i can see (whether it is a reall issue or not...?) is that even after calibrating the TPS.At the 0 position it is sending back -1 to -4 responses randomly. these seem to coincide with when the idle goes wacky, then it settles down till the next - reading...this may a chicken / egg issue though....

Do you guys think this could be a ground isssue, incorrectly calibrated issue or a faulty TPS issue (worked/works fine with link ecu though).

Also, further to the grounding thing, do all you guys run seperate grounds from each sensor direct to the ecu or is there an easier / tidier way?

Okay, I have solved my idle up to -4 TPS problems, the info above lead me to the solution BUT the info above is a bit misleading fro Rev built enhanced MS2 ECU's.

After soldering 3 ground wires to pins 7-19 in prepration to ground the ECU correctly (as per the above info) I decided I should double check against the pinout that comes with Rev's instructions.

It turns out his pin outs are TOTALLY different to the normal MS ones and the link above (whilst it was indirectly helpful) is incorrect.

Pin 3 of the Rev built enhanced MS2 is his designated analogue ground. Wiring my TPS to this was the solution.

So for future reference in the forum - I am not sure what will happen to your Reverant built enhanced MS2 if you ground pins 7-19 but I don't imagine it will be a good thing....

The same reasoning can be applied to the use of the PGND and SGND (signal ground) pins on the MS:

https://www.miataturbo.net/attachmen...1&d=1378353874

https://www.miataturbo.net/attachmen...1&d=1378353874

I'm sure rev must have a reason for pin 3, it's a spare either way. Good to know for future reference since there are a lot of rev built ms out there.