blkyata

Hello, I recently installed my ms3pro pnp into my miata nb1. I am having a problem where my battery voltage is getting about .6 - .8 less voltage from my tuner studio, I checked my battery with a multimeter and the terminals to see what they were getting which was around the 12.5 range, and my tuner studio was reading about 11.6-11.8. The car will start fine if you jump it, and tuner studio will hold at 14.5 volts, but once it gets shut off the voltage drops slowly. I will attach a video at the end of this via URL. My tuner was telling me I have a bad ground somewhere, but I am not sure about this as I've never had a problem with my battery before I swapped over to Megasquirt for my turbo build (which was right before this).
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Things I've tried:
The only wiring I've messed with is for the radio/cigarette lighter, I checked my wiring and it looked perfectly fine. I also pulled fuses to remove complete power to the radio, ac, room, etc to see if the voltage would match, but still nothing.

I cleaned the ground on top of the throttle body and the one behind the dipstick with some sandpaper, and the battery terminals were tight

I unplugged the fuel pump because I thought maybe that was my issue, and it still was not my issue
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If anyone can lead me in the right direction please do, I need to get this fixed as my tuner wants this to be fixed before he continues tuning my car. This is my daily and I am starting my Spring Semester in a couple days so I need to try and fix this issue to get the tune finished. Any help is greatly appreciated, I also attached my tune file if anyone wants to check it out to see if something is wrong with it.
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LINK TO VIDEO:
https://streamable.com/rumrco
Expires in two days, can reupload video if anyone needs to watch it

Stoffl

Well first off you need to verify if the voltage measured with a multimeter at the relevant ECU pins / ecu harness is the same as shown in Tunerstudio. If not, there's some adaptions you can make in Tunerstudio.

If that measured voltage is differing too much from actual battery/alternator voltage(measured in engine compartment and trunk) then you DO have some wiring or ground issue.

blkyata

Hey, sorry for the late reply, I've been trying to figure it out. I removed my MS3 and turned the car into accessory, and checked the battery, reading about 12.50, The alternator reads the same, alongside the ECU Pins which were giving power. So now I'm assuming its software/ECU related? Why would my voltage be dropping like that, it's really weird.