poor mileage [Archive] - TheDieselGarage.com

: poor mileage


Orangepstroke
01-11-2011, 09:38 PM
before i put in the imjectors, dv, turbos, timing, etc. i was only getting 15mpg. only mods were afc gutted and no plate. intake, exhaust, and gsk.
now im getting 14-15 mpg modded. why is the mileage so bad? is it cuz the afc isnt tuned. wouldnt think it would make that big of a difference just crusing down the highway.

BUCK2
01-11-2011, 10:14 PM
It will make a difference in the fule mileage! Also my right foot makes a big impact on my mileage!

Orangepstroke
01-11-2011, 10:31 PM
i understand the right foot. but i usually have the crusie set at 75 on hwy get maybe 400 miles to a tank.

floridaboy
01-11-2011, 10:53 PM
might be the injectors???? not sure tho....... might bump your time a few more * and you might pick up some more mpg.....

SSpeeDEMONSS
01-12-2011, 12:15 AM
put the afc back together and tune it.

i was able to do 16-20 with 4.10s and dealing with L.A. traffic daily. i would do 500mi easily on a tank, did over 600 a few times as well.

Garrett

cummins power
01-12-2011, 12:24 AM
Dirty air filter?

keydl
01-12-2011, 02:19 AM
I think that I would start with the basics, tire pressure, tire rating E, are the brakes dragging, wheel bearings (temperature for balance to start), toe-in, wind drag... you started at 15, it should have been 20-21.

Six years ago I was driving a ton truck - the co had 2 the same - I made 16 mpg and the other made 9, we traded trucks and had the same results I made 16 with the truck that had been logging 9 and my truck made 9 with the other driver. It even made 16 when I put the Isuzu on a towbar to relocate, I took care to control windage with tarps and run easy. The other fellow drove comfortable - both feet on the floor when I rode with him.

cummins power
01-12-2011, 03:50 PM
Does that pickup have 4.10s or 3.55s?

bmoeller
01-13-2011, 05:25 AM
The flatbed is hurting your mileage. I lost 3-4 mpg putting one on my '97 dually.

Even with 4.10 gears, I got 16mpg stock with it. And nearly 18 after I modded it. Flatbed knocked me back to 12-15 range. Mostly 13-14, highway or not. No matter how I drove.

Orangepstroke
01-13-2011, 10:40 PM
Yeah it don't matter. If I'm towing haulin or empty. Same mileage. Tires, bearing, alinement, etc everythings good.

bmoeller
01-22-2011, 09:50 PM
Put the plate back in and reassemble the AFC and tune it.

I dynoed 416hp/892tq with my '97.

TST 10 plate and AFC housing full forward, adjusted star wheel, 191DVs, DDP stage 4 injectors, HTT Killer B2 64/14, ATS exhaust manifold, BHAF, 5" exhaust to 5" turn-out stacks. And, got the aforementioned almost 18mpg.

later
01-23-2011, 04:14 AM
Put the plate back in and reassemble the AFC and tune it.

I dynoed 416hp/892tq with my '97.

TST 10 plate and AFC housing full forward, adjusted star wheel, 191DVs, DDP stage 4 injectors, HTT Killer B2 64/14, ATS exhaust manifold, BHAF, 5" exhaust to 5" turn-out stacks. And, got the aforementioned almost 18mpg.

:whs More than likely you are over fueling before the turbo can spool and just wasting fuel. The fuel plate will limit that.

SSpeeDEMONSS
01-24-2011, 05:03 PM
:whs More than likely you are over fueling before the turbo can spool and just wasting fuel. The fuel plate will limit that.

AFC will limit that. no need for a plate.

Garrett

mrod67
01-24-2011, 11:39 PM
Just for hahas check fuel pressure. I had a customer with a 95 12v burn through a tank in 100 miles. I found absolutely nothing wrong except low inlet fuel pressure. I put a new overflow valve in and it was fixed. I seriously thought someone was stealing his fuel, but he claimed he didnt do anything different, and the next tank was 500+. Probably not your issue, but worth a shot.

Orangepstroke
02-03-2011, 06:44 PM
is there a good place to stat when adjusting the star wheel and preboost screw?

later
02-03-2011, 11:30 PM
All the way back then 2 rounds out.

bmoeller
02-05-2011, 11:38 PM
I had mine full forward, til i went to Colorado. Air is too thin up there to spool the 64 worth a crap. Put it back towards the middle helped and I kept it there. Worked pretty good.