Fuel mileage?

[enjoi.this]

I have an 87 Turbo and was getting around 200 miles to a tank of fuel.
My fuel pump died so i changed out to a walbro 255lph pump and now im getting 250-300 miles to a tank. Now my question is how am i getting better mileage now?

 

[sneakypete]

sounds like you just answered your own question....

 

[snake eyes]

not very bright are you? If it increases the miles per tank... um, then yes

<l><l>

 

[mkiii222]

I don't know how you think he answered his own question.

If his fuel pump was going, it would have been giving less fuel than it was supposed to. He now has installed a pump that should push more fuel through it than stock. But for some reason he's getting better mileage (4+ mpg from the sounds of it).

I'm sure someone will chime in with a better answer, but I'd say the tired pump presented lean conditions sporadically that caused the ECU to ask the pump for more fuel. (running it even harder making it deteriorate further) Once you put the new pump in (resetting the ECU in the process since the battery should have been unplugged) the ECU learned that if it asked for x amount of fuel it gets it.

If a tired pump wastes that much fuel, I have another project this winter since I've still got a stock pump.

 

[noel]

wouldnt a walbro waste more gas? getting better mpg is not only depended on walbro :biglaugh: i dunno just my 2 cents

 

[mkiii222]

I'm sure someone will chime in with a better answer, but I'd say the tired pump presented lean conditions sporadically that caused the ECU to ask the pump for more fuel. (running it even harder making it deteriorate further) Once you put the new pump in (resetting the ECU in the process since the battery should have been unplugged) the ECU learned that if it asked for x amount of fuel it gets it.

wouldnt a walbro waste more gas? getting better mpg is not only depended on walbro :biglaugh: i dunno just my 2 cents

 

[enjoi.this]

I just thought of an idea on how my fuel milage could have increased. Since the fuel pump was failing and leaning out my afr, with the ecu running the fuel pump harder which in turn = heat. If the pump was run really hard all the time i was probly heating the fuel in the tank which evaporated it instead of actually burning it. Just a thought..

 

[CATarga]

The gas wouldn't have evaporated just expanded from the heat and increased the amount of vapors in the tank(more pressure). As long as the fuel system is working correctly. i.e, no leaks in the sending/return lines/gas cap, the expanded fuel would remain in the tank, even in a vapor state. Do you here air escaping from the tank when you crack the fuel cap? If you don't then you could have lost some fuel there, but not 25&#37; loss in mpg's.

 

[enjoi.this]

Yeah thats true it is a closed loop system.. and my tank is pressurized when I fill up each time.