MS3x Nitrous In and JP8 question
Thread Starter
Joined: Apr 2014
Posts: 18,643
Total Cats: 1,870
From: Beaverton, USA
Reading step 31 here: Megasquirt-3 MS3 DIY board assembly manual
It says that custom firmware is required to use the jumper on JP8.
But here: https://www.miataturbo.net/megasquir...e2/#post815941
Brain says to just jump it and it gives a pullup.
By custom firmware do they just mean custom settings in the tune?
Also what gauge wire should I be using to connect the Pins of my ECU connector to the outputs of the MS3x and MS3.
It says that custom firmware is required to use the jumper on JP8.
But here: https://www.miataturbo.net/megasquir...e2/#post815941
Brain says to just jump it and it gives a pullup.
By custom firmware do they just mean custom settings in the tune?
Also what gauge wire should I be using to connect the Pins of my ECU connector to the outputs of the MS3x and MS3.
Thread Starter
Joined: Apr 2014
Posts: 18,643
Total Cats: 1,870
From: Beaverton, USA
Instead of starting a new thread I'll just continue this one. Hopefully someone has an answer:
Ok I'm stumped. It worked on the bench but now it won't work installed in my car. Any ideas?
I get 12v at power and ground. And it shows up in my devices. But tuner studio can't connect to it
Ok I'm stumped. It worked on the bench but now it won't work installed in my car. Any ideas?
I get 12v at power and ground. And it shows up in my devices. But tuner studio can't connect to it
Thread Starter
Joined: Apr 2014
Posts: 18,643
Total Cats: 1,870
From: Beaverton, USA
Update: Testing on the car i get .25 volts where I should be getting 5 on the CPU connector. I get 11.38 On the left leg of U5.
With the current firmware, JP8 should be left off.
Thread Starter
Joined: Apr 2014
Posts: 18,643
Total Cats: 1,870
From: Beaverton, USA
Thread Starter
Joined: Apr 2014
Posts: 18,643
Total Cats: 1,870
From: Beaverton, USA
Megasquirt Support Forum (MSEXTRA) • board voltage wrong (View topic)
Reading there I have 5 volts at all those places except for D19.
I wish I had a schematic of this board. I'm lost at what everything does.
Reading there I have 5 volts at all those places except for D19.
I wish I had a schematic of this board. I'm lost at what everything does.
Thread Starter
Joined: Apr 2014
Posts: 18,643
Total Cats: 1,870
From: Beaverton, USA
Braineack, any idea on this?
So everything was going great:
maybe a bit rich. But then this happened...

Smoke everywhere and the wire burnt up. Its too late and it pissed me off so I am going to bed. Any ideas why this happened? The engine continued running while this happened. I have they flyback diodes wired in there.
It seems to be the 12v power wire that burnt up.
EDIT: I dug around and the 12v wire that went to the flyback diode burnt up along with the wire that goes from the fan output (Inj G) to the diode. The wire from the diode to MS3x pin 1 is fine, and so is the power wire in other places.
EDIT 2: Also I didn't jump the fuel pump relay and it still ran, this weirded me out. Any ideas?
So everything was going great:

Smoke everywhere and the wire burnt up. Its too late and it pissed me off so I am going to bed. Any ideas why this happened? The engine continued running while this happened. I have they flyback diodes wired in there.
It seems to be the 12v power wire that burnt up.
EDIT: I dug around and the 12v wire that went to the flyback diode burnt up along with the wire that goes from the fan output (Inj G) to the diode. The wire from the diode to MS3x pin 1 is fine, and so is the power wire in other places.
EDIT 2: Also I didn't jump the fuel pump relay and it still ran, this weirded me out. Any ideas?
Last edited by aidandj; Sep 27, 2014 at 01:41 PM.
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