Ok, I've had my truck exactly a year.

I usually keep a descent eye on fuel mileage.

So, heres a question

Do injectors throw the overhead display way the heck off?

I am running 315s and 3.55s. I was getting a very consistent 16.8-17.2 hand calculated(with speedometer error calculated in). Overhead usually read 15.2-15.5, this was in the winter with a Van Aaaken, 4" and AFE.

Then I switched to Juice and Summer fuel, got between 17.5-17.9. Overhead said about 16.2 or so.

Then I put the injectors and clutch in and fuel mileage jumps way up. My overhead currently reads 18.4 MPG after 350 or so miles on the injectors. I figured I was getting 20+. But I filled up and only got 17.1 MPG.

My truck came with 265s and speedometer/odometer is about 11% off with 315s. Usually adding 11% to the overhead is very close.

18.4 should really be 20.4 MPG.

But I get 17.1 MPG? So do injectors really throw it off that much as in 3.3 MPG?

I am thinkin I might of not filled it all the way last time I filled up because I have added 2 or 3 gallons(would be close to error) after the pump shuts off automatically before. My fuel gauge sucks and cannot be trusted. I put 13 gallons in and gauge said 3/4 tank. Its off by almost 1/4 tank most of the time.

Anyways, if I didn't mess up. I guess I am dissapointed with my Mach 1.6s. Good power increase, but lose 1 MPG.

Also, I replaced all the injector tube O rings. All the lines seem to be tight and I can't find any leaks. Oil level is the same. And I would think I would smell it if I lost 2 gallons of diesel over 350 miles.

 

Here's what I recomend with the overhead mpg display is you turn it off or turn it to the compass/temp. I consider them utterly useless, mine says 30 mpg because of my smarty, 1.6's, and HRVP throw it off so far. The only way to get accurate mpg numbers is to hand calculate and the only thing to overhead is good for is the compass/temp.

 

when I got 21 mpg my overhead read 33




no bad mileage for 400 hp. stock tire size

 

my overhead always was around 20-21. after stage three jammers it went to 28-30. now after i put 3" taller tires on its down to 24-25.

 

According to the overhead, I was getting 24 MPG pulling our 5th wheel on I-10 between San Antonio and Houston on Memorial Day. Wanna guess how close that was when I filled up?

Rusty

 

My overhead usually says 33 mpg also with Mach 4s. And like Bob I'm normally in the 21 range if I'm behaving on that tank.

 

Mine usually reads about 34-37mpg with just the mods in my sig.

 

My overhead always reads 4mpg better than my hand calculated mileage for some reason. Since I put the EZ it's never been accurate. Eric

 

With the TST on setting one 99% of the time, mine reads an overall average right now of 40+. Generally, the instant reading going 65mph on the highway is between 60 and 99. True economy on mine averages 18-20.
andy

 

Huh? Wonder what I'm getting, mine reads 14.7

 

I kept track of the computer's milage along with calculated milage, at every fillup, for over 50,000 miles, trying to figure out a mathmatical formula to get actual fuel mileage from the computer. Finally gave up because the two figures were so inconsistant. Use only calculated milage now.