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Old 06-08-2012, 04:50 AM   #41
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I wonder that Frank never had problems with that...

(Edit: Now I see a very clear advice about grounding on Frank's page - it wasn't there at the time I did my build, good thing that Frank added that)

I am surprised that the car did even run...


So I will just make a connection between the MS3X and the Mainboard DB 37 ground pins/connectors...

Last edited by Zaphod; 06-08-2012 at 08:33 AM.
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Old 06-08-2012, 08:45 AM   #42
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run the grounds from teh ms3x direct to the block!!!! STATEN ISLAND!

dont connect back to harness...but if you do make sure they only connect back to main grounds, no sensor grounds....these are high current grounds.
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Old 06-08-2012, 09:49 AM   #43
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I got this

Quote:
5. All of the ground pins 1,2,7,8,9,10,11,12,13,14,15,16,17,18,19 are connected together within the Megasquirt. The above diagram shows certain pins used as dedicated sensor ground returns - this is good practice, but so long as the sensors are grounded AT the Megasquirt, the particular ground pin number does not matter (i.e. do not ground the sensors to the body or the battery or the engine.) Likewise the power grounds - these are shown at the right of the connector because this makes them electrically closer to the high power components within the Megasquirt, but all ground pins are connected together so alternates can be used. These power ground connections should go direct to the engine block (not the battery and certainly not the body.) Poor grounding by the installer usually results in installation problems.
from here:
http://www.msextra.com/doc/ms3/hardware.html#wiring

How would I make sure that they don't connect with sensor grounds, when the sensor ground are connected with the main grounds in the MS3 anyway...
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Old 06-08-2012, 10:03 AM   #44
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that's why youre supossed to run them seperatly to the block. Ken yells at me for this.

but ideally, you ground the sensors THROUGH the MS and no where else on the car. Notice the diagram you posted.


anyways, just get the grounds to the MS3x and win at life already.
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Old 06-08-2012, 11:07 AM   #45
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I tied all of the MS3X grounds together and connected them to the OEM connector at pin 3A - everything is right as rain now...

Thanks for babying me through this...

Engine is running rich as ---- now, also I will have to retune the idle settings, AE etc...

Last edited by Zaphod; 06-08-2012 at 12:54 PM.
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Old 06-11-2012, 03:02 AM   #46
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As I got my problems solved - I thought a little more about the grounds for the MS3X.

At the moment I connected the MS3X grounds to pin 3A at the main harness, together with another ground for the Mainboard.

Here is a screenshot from the wiring diagram of the 99 1,6 car.


As you can see - all 3 pins (3A,3B, 3C) of the main harness are going to the same ground spot Nr. 5 - at the front of the intake manifold. But 3A and 3B are tied together somewhere, whereas 3C seems to go as a single ground wire to the same spot.

Would it make sense (from an electronics point of view) to use 3A/3B for the MS mainboard and 3C for the MS3X grounds, (To keep the noise as low as possible) or will this not matter, as they are using the same ground spot anyway...? (I am not too much into that electronics kind of stuff - so please help me out)
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Strange Boost control / AFR problem-ground_scheme_b6.jpg  
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Old 06-11-2012, 03:04 AM   #47
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I would use 3A and 3B for the MS3X and 3C for the MS3 mainboard.
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