Tuner Studio reading wrong voltage
 

I'm running MS1 on a 95 turbo car. In tuner studio it shows 13.6-almost 14 volts. At the battery it reads a normal 12.5-12.7 while running. Also tuner studio shows no draw when headlights, heat, radio or any combination of voltage drawing accessories turned on. Can I compensate with easy therm or is there another way to correct this. Thanks for any advice

Uhhh you should be ~14V while running...

Ya but why would it read different at the battery? Running or not. It seems to run good but I think it's over compensating the injectors

What are you reading it at the battery with? If DMM, when is the last time you changed the battery in it?

Reading with a fluke/volt meter. Battery is 2 years old.

Sorry but, DMM?

Digital Multi Meter. Change the batteries and check again. Or check with a different meter altogether

MS needs to match voltage as read at the injectors.

if you're only reading 12v while running your alternator isn't working.

^ This.


The battery should read around 12v when the engine is not running.

A basic principle of electronics is that in order for current to flow from the alternator into the battery, the voltage produced by the alternator much be higher than the battery voltage.

A comparable scenario here would be if you had two balloons connected to one another via a straw. In order to force air from one balloon into the other, you squeeze the balloon, causing the pressure (voltage) inside it to rise. Air then flows from one to the other until the pressure equalizes between the two.

Same deal here. In order for the battery to actually charge, the alternator is run at a higher voltage than the battery's normal resting voltage; the exact voltage differs somewhat from car to car, but 13.8v is often cited as the ideal, with observed readings ranging from around 13.5 to 14.5v.

If you read less than this at any point in the system while the engine is running, you have a problem. Maybe a bad alternator, maybe a wiring problem in the car, maybe your meter is just out of calibration or malfunctioning. These things happen.

So I may not have a problem..... I'm gonna try and check the voltage at the injectors to see if it matches. My tuner was saying the extra voltage will over compensate the injectors. Is this true? What you guys said makes sense. Thanks for the help!

voltage has an effect on the dwell time of injectors, so MS adjusts the PW of the injectors based on the system voltage in order to compensate correctly.

that's why it's important that the MS is tuned to match the voltage at the injectors.

you might see 14v at the battery but only 13v at the injectors.

I know this is a very old thread but I wanted to ask is there an easier way to measure the voltage at the injectors other than at the pigtails or in thay area where access is not ideal? Also does the car need to be running? I am trying to verify voltage and this thread came up as a relevant one.