2nd Gen Non-Engine/Transmission On board fuel calculations

[GaryC 2001]

Does anyone know how the computer calculates the fuel consumption on the 2nd gens? And before anyone starts yes I can do my own math. It has become way off and I'd like to know if I could get it recalibrated it used to always be within a few tenths now it's off by miles it's more of on of those things just drives me crazy because it used to be accurate and now it's not right

 

[B.G. Smith]

I think it is calculated from signal from throttle position sensor and speed sensor.

 

[Bob4x4]

There is no calibration available. You can bet the boost sensor is also used

 

[SAndreasen]

Mine used to be only off buy a mpg consistently but then I added a bully dog programmer and the mpg was off 4 or 5 mpg or more never could get anything useful out of it after that

 

[Bob4x4]

Mine used to be only off buy a mpg consistently but then I added a bully dog programmer and the mpg was off 4 or 5 mpg or more never could get anything useful out of it after that

Once the pulse width has been changed all bets are off

 

[Road Dog]

It's simply a calculation based on the RPM and injector pulse width (from the ECM). Using a programmer to add fuel or changing the injectors will make the calculation meaningless. If you're using more fuel then maybe you have one or more leaking injectors.

 

[Bob4x4]

It's simply a calculation based on the RPM and injector pulse width (from the ECM). Using a programmer to add fuel or changing the injectors will make the calculation meaningless. If you're using more fuel then maybe you have one or more leaking injectors.

You are also not taking into account rail pressure in the crd's

 

[Road Dog]

True, but we're talking 2nd gen here with a VP-44. In any case the fuel consumption is calculated. There's no flow sensor.