When I bought my 84 Excella 270, it came with the stock 7.4L motor with a Quadrajet carburetor. Mileage was about 7MPG and I wanted to get better MPG and eliminate the endless cranking waiting for fuel to get to the engine.
A few years ago I installed a TBI kit from AFI and with some difficulty, I got it installed and working OK and the install is documented here:
My gas mileage did not improve much, maybe .5 to 1 MPG intermittently.
On my last wander of about 300 miles I tried 93 octane in the tank, I had 10 gallons of regular (87 octane) and added 20 gal of 93 and at mid trip I added another 15 gal of 89. So overall the octane on the trip was higher than regular grade. The end result was about 8.5 MPG and that was loaded medium heavy with an extra ton of trailer in tow.
A friend mentioned that I may get better mileage with regular if I had a knock sensor for my ECM. The designer of this kit claims a knock sensor is not needed and usually causes more problems than it solves, so it was not included. With the 6 to 7 ton load and long stretches of hills our vehicles endure, I wonder who is right?
Anyone out there with experience with knock sensors on MH engines, or any other solutions to better mileage?
(Skipping Banks headers, they are beyond my budget)