vpshockwave

Hey guys,

LG just got done doing some work to my car and I have a question (since they're not open on the weekend). I had a bunch of work done, but I have a question specifically about the injector size in relation to the MPG readout on the DIC. I went from the stock injectors to 42 lb/hr injectors and I was watching my MPG on the way home and it showed I was getting great cruising MPG, but it seemed like I was actually using gas faster according to the gauge (could've been my imagination though). Now obviously I don't drive the car for MPG, but I would like to know if that reading is accurate or not. I know even stock it's not perfectly accurate, but is it possible that this reading is off a large percentage because of the injector change? If so, is there a way to change something in the computer so that it can read more accurately?

Thanks guys

neutron82

pay attention to the actual mileage and not the dic

vpshockwave

I'm trying to be as nice as possible here ... but ... did you read any of the questions I asked?

beboggled

neutron82

my point was that the dic avg mpg is not an accurate way to calculate your mileage hence why you're confused about why your gas gauge is going down fast but it says you get great mpg on the dic... I think it is more related to the tune and other mods like a cam that demand more fuel rather than the injector size... as far as changing anything in the pcm to correct it I have no idea

vpshockwave

Thanks for trying to help but you'll note that I mentioned I already knew the DIC wasn't perfectly accurate even on a stock car. It's a decent guideline to go by though.

2003Evo

Changing the injectors should not effect the DIC reading IF your injector duty cycle is set properly. Your mpg (DIC) reading will depend on your injector duty cycle and how much fuel is being commended. Its hard to tell from your statement since all you say is injectors were changed..what else do you have done to it? Power? A/f ratios at wot, part load and steady state? All these things effect your dic reading and mpg.

Cliff8928

A while back I did a quick fix for running lean on mine and just changed the injector size smaller in the tune, this made the MPG skyrocket. It claimed around 32 MPG around town.

vpshockwave

I had heads, intake manifold, throttlebody, fuel rails, and injectors all done, plus an updated tune. I just mentioned injectors because I figure that was the one thing directly related to raw fuel consumption. Is the duty cycle you're referring to something that would need to be changed during a tune with this many component changes? Or is it possible it was skipped?

Thanks guys!

95wht6spd

It will show better mpg with the bigger injectors if it was not adjusted for in the computer. I had this happen on a car with H/C and 42s.

2003Evo

Duty cycle is set when the car gets tuned, your tuner will set that.