Quote:
Originally Posted by brucepick
After driving several tanks with the EPES which runs mostly around 12.5V instead of the alternator's approx 14V, I found my MPGuino consistently reporting somewhat more fuel usage than the car actually consumed.
I expect that the fuel pump is running at somewhat reduced pressure at the lower voltage. So for any given injector pulse length, less fuel is being injected. The MPGuino reads pulse length, so needed an adjustment for use with the EPES.
Anyway, the correction I needed was right around 3%.
FYI. YMMV.
|
WOW!, I suppose you could hook up a fuel pressure gauge to the fuel line to test this, although if the 3% directly compares to 3% less fuel pressure, then it will be hard to tell unless you have a really acurate gauge.
I'm wondering if the same thing is happening to me, because monitoring my voltage while driving with the alternator on, it will go for miles without going above 12 volts, then it shoots up for some reason. On the highway today I noticed that it almost always stayed at 13-14 volts even with a low accessory load. I don't know if that's because the injectors and ignition were using a lot more electricity on highway use, or if it figures at higher speed you can charge faster?