IDI pump adjustment

[Jarrod B]

i asked on another thread and was told maybe and its most likely its already set for best mpg to power ratio.


but im askin if i turn the pump down lower than stock, yes i know it will not have power, but doing that, will mpgs raise?


basically aiming for a dd with higer than normal mpgs.

thinkin of a 2wd SC LB 5sp

[Crawler374]

it doesn't really work like that. less fuel to the engine, means too much air, probably won't start, and will loose ALL power.

I say lay of the skinny pedal. Keep RPM's under 2k, and put a electric fan clutch in.

[Rubenk]

A diesel wont gain mpg from allowing less fuel. Essentially your foot is what determines the mpg. There is no throttle, the fuel put into the motor is directly controlled by you, especially on older motors.

[jethro]

you would probably kill your truck imo that is a terrible idea

[Jarrod B]

ok seems like its a bad idea. didnt think about the air tho.

thanks guys

[FordGuy100]

It wont kill the truck. Probably wont even do any harm. High altitude pumps came factory de-tuned to allow less fuel (higher altitude plus N/A means high EGT's). You will loose power, yes. All IDI's have the sticker indicating if high altitude or not. I think my motor stock was rated at 175hp, and high altitude was 158hp.

Find a F150, an IDI+ZF combo. We will place it into F150, and you will achieve 25-30mpg easy. I know of one guy who did it for his son. Truck weighs 3000 pounds so you can basically let the motor idle along and get great fuel mileage.