Can anyone make sense of my live data please?

[Stetec]

Used my bluetooth OBD with Car doctor app, I've got intermittent low rev/part throttle misfire, car feels lacking in torque, idle fluctuates, lights pulse at night, battery voltage varies between 9 and 16 volts while engine is running. Could this be voltage regulator in alternator issue?

These are the numbers I got with the car sitting at idle and warmed up tonight, any help appreciated as Im getting seriously demoralised

Live data


Fuel Response time = 270-330 ms
DTCs Mil off, spark, ignition
Calc engine load = 28-31%
Coolant = 177 degrees farenheit
Short term fuel trim bank 1 = (-4) - (-7) %
Long term fuel trim bank 1 = (-8.5) - (-9.4) %
In take mal pressure = 0.29 ATM
RPM 740 - 820 rpm
Timing advance = -0.5 - 12.5 degrees
Intake air temp = 86-94 degreees farenheit
Throttle position = 9.41%
O2 sensors = 00000011
Bank 1 O2 sensor vlotage short term fuel trim = 0.20v (-5) - (-7) %
Bank 1 sensor O2 voltage long term fuel trim = 1.275v (-5) - (-7) %

 

[Stetec]

No one?

 

[Stoo.]

Apart from the engine load calc (Which seems high for idle!), those figures won't tell you much...

Battery voltage when running should be very stable, c.14.5v, so I would think about the rectifier tbh

 

[Stetec]

Thanks stu I'm wondering if the reg is causing the idle to flux or the idle being rough to cause the voltage across the battery at idle

 

[Stetec]

By rectifier do you mean the regulator

 

[Stoo.]

Rectifier changes the AC voltage in to a DC output, the regulator ensures that the output voltage is as constant as can be.

Should be about 14ish volts.

I think the fluctuating voltage will be causing the problem, not the idle fluctuating creating the voltage drop as that should not happen if the reg is working.

Either way, it's an alternator problem by the sounds of it...

 

[Stetec]

Cheers stoo