Max MPG checklist...

[dirtboy25]

It didn't really bother me at first that I was only getting 13 mpg out of my truck but now it's starting to bother me.

I'm running full synthetic oil in the motor. My HPOP is in freakishly good shape. I have no fuel leaks, and no performance problems that I can hear or feel. Other than the wheels and tires the truck is stock.

What are things I can check, change, or upgrade to improve fuel mileage? I've thought about running Royal Purple in the axles, and tranny but at ~$20 a quart I'd hate to spend that money and not see much of a result. How much will a lower valance help? I'm sure all the little things will add up but compared to my old CCSB 4x4 that got 17-18 mpg this thing is killing me.

First i'm going to get some tuning, maybe that will help. My other chip fried on me and I have yet to get a new one.

I have about 2k to spend on this project. I want to see results!

 

[stroker2]

Truck in my sig gets 22.5 mpg on about 95% highway, 5% in-town running 70mph average. passing in oncoming traffic every now and then. 3.73 gears and 34" in tires.

I think your best to start with 4" exhaust, good intake, and some tunes. im betting that my 1.00 exhaust housing on my 38r helps also compared to the stock .84

 

[BigAlsPSD]

It didn't really bother me at first that I was only getting 13 mpg out of my truck but now it's starting to bother me.

I'm running full synthetic oil in the motor. My HPOP is in freakishly good shape. I have no fuel leaks, and no performance problems that I can hear or feel. Other than the wheels and tires the truck is stock.

What are things I can check, change, or upgrade to improve fuel mileage? I've thought about running Royal Purple in the axles, and tranny but at ~$20 a quart I'd hate to spend that money and not see much of a result. How much will a lower valance help? I'm sure all the little things will add up but compared to my old CCSB 4x4 that got 17-18 mpg this thing is killing me.

First i'm going to get some tuning, maybe that will help. My other chip fried on me and I have yet to get a new one.

I have about 2k to spend on this project. I want to see results!

EBPS: Exhaust Back Pressure Sensor (and tube). Clean these and replace if necessary. Dont forget to clean the hole in the manifold too.
MAP Sensor: Check for leaks.
IC Boots: Check for leaks, including the boots under the spider.
Turbo: Check for leaks around where the turbo outlet meets the spider.
Up Pipes: Leaks in the up pipes WILL cause a drop in MPG. Exhaust gas leaking here will cause the turbo no to spool up as much or as quickly, causing the truck not to burn fuel properly. It goes back to the stoichiometric ratio. If the air:fuel ratio isn't right, its wasted energy. Your truck is a finely tunes machine. Any deviation from its planned path will decrease efficiency.
Fluids: Pretty basic. Change ALL fluids in the drive line (or better yet all of them). As I mentioned any change in your truck's anatomy will decrease efficiency (this goes back to changing to coolant too).
Driveline: Physically follow the drive line. Check everything for hand ups. Excess play in the driveshaft or ujoints can cause drag.
Hubs: Service your hubs (30 mins each) and you can fix this. It causes drag on your wheels by turning the entire front drive system.
Check for Fuel leaks as well.


Brake Caliper Pins: It is very possible your breaks are dragging, its a common problem. Service/Replace your break caliper pins.
Air Filter: Bigger Air filters equal more air in, making more power. However, most big filters (6637) delete the factory air box and suck in hot air. Hot air is less efficient. If you can, re-install the stock air box or get an aftermarket filter with a CAI. At least until you narrow down the leading cause of MPG leaking..
Injectors: If your injectors are partially clogged your fuel will not atomize properly, causing inefficient and inconstant burning.
HPOP Oil Pressure: Same rules apply. The HPOP actuates the injectors. Low pressure will cause the injectors to fire weak and not atomize fuel properly.

 

[TyCorr]

One of the.biggest that nobody ever mentions is air pressure in the.tires. Check weekly! In a matter purely interested in fuel.economy the stock airbox is fine. Fuel.economy has shti to do with high gas flow rates. Same for exhaust. A stock truck with maybe taller, not wider though, tires will.reduce.the.effective gear ratio and could reduce.rpms.for cruising.

Honestly, ignore every mod. Air your tires.up to the.max +15-20%. That reduces rolling resistance. Keep the rpm output as low as you can to reach your speed desired. That speed should be 60mph or.less for maximum economy. Ditch anything you dont neex to.keep your overall weight minimized. If thisdoesnt gain something than your.driving technique is not.conducive to decent mpgs. Its no mystery that economy is putting out.the.least you have to to get your results desired. A tune will most likely ellicit aggressive throttle application from you.

 

[PatriotHauling]

EBPS: Exhaust Back Pressure Sensor (and tube). Clean these and replace if necessary. Dont forget to clean the hole in the manifold too.
MAP Sensor: Check for leaks.
IC Boots: Check for leaks, including the boots under the spider.
Turbo: Check for leaks around where the turbo outlet meets the spider.
Up Pipes: Leaks in the up pipes WILL cause a drop in MPG. Exhaust gas leaking here will cause the turbo no to spool up as much or as quickly, causing the truck not to burn fuel properly. It goes back to the stoichiometric ratio. If the air:fuel ratio isn't right, its wasted energy. Your truck is a finely tunes machine. Any deviation from its planned path will decrease efficiency.
Fluids: Pretty basic. Change ALL fluids in the drive line (or better yet all of them). As I mentioned any change in your truck's anatomy will decrease efficiency (this goes back to changing to coolant too).
Driveline: Physically follow the drive line. Check everything for hand ups. Excess play in the driveshaft or ujoints can cause drag.
Hubs: Service your hubs (30 mins each) and you can fix this. It causes drag on your wheels by turning the entire front drive system.
Check for Fuel leaks as well.


Brake Caliper Pins: It is very possible your breaks are dragging, its a common problem. Service/Replace your break caliper pins.
Air Filter: Bigger Air filters equal more air in, making more power. However, most big filters (6637) delete the factory air box and suck in hot air. Hot air is less efficient. If you can, re-install the stock air box or get an aftermarket filter with a CAI. At least until you narrow down the leading cause of MPG leaking..
Injectors: If your injectors are partially clogged your fuel will not atomize properly, causing inefficient and inconstant burning.
HPOP Oil Pressure: Same rules apply. The HPOP actuates the injectors. Low pressure will cause the injectors to fire weak and not atomize fuel properly.

Sounds familiar.. LOL

 

[BigAlsPSD]

Sounds familiar.. LOL

Still great information :thumbsup:

 

[dietoremain]

What they said ^.

 

[TyCorr]

Ivs checked bearings before when fuel.economy.drops. A great running truck that out of ***kin nowhere drops 15% economy is one.that will shortly reveal.a.mechanical failure.

 

[stroker2]

Ivs checked bearings before when fuel.economy.drops. A great running truck that out of ***kin nowhere drops 15% economy is one.that will shortly reveal.a.mechanical failure.

I went on a 2 mile run a bit ago and been trying to catch my breath...not sure if that post helped or hindered that oke:

 

[MadDiesel73]

Right foot delete.

 

[stroker2]

Right foot delete.

or just drive downhill

 

[TyCorr]

@op- what I.said.is true. If you were getting 16+ and now 13. You lost efficiency somewhere, as long as your driving style didnt change. Have your egts evolved with the fuel.economy?

There are so many places to.check its pretty tough to help on a forum.

 

[dirtboy25]

@op- what I.said.is true. If you were getting 16+ and now 13. You lost efficiency somewhere, as long as your driving style didnt change. Have your egts evolved with the fuel.economy?

There are so many places to.check its pretty tough to help on a forum.

I've never gotten better than 13.5mpg. Even when recorded with stock sized tires/wheels. EGT's run no higher than 100* per 10mph. My hpop is very good, no leaks, no boost leaks (that I can hear) and boost gauge reads properly for a stock truck. Tranny shifts great, the truck tracks fairly well down the road but I have yet to have it aligned.

The truck sat for nearly 3 years without being moved. The last service record I found was from fall of 08, and when I bought the truck a few months ago there was about 150 miles more on the OD than there was recorded on the last service receipt.

I've replaced all fluids except for rear end, and replaced all filters.

Brakes are new, u-joints new, hubs are serviced, trans looks like it has very few miles,... I'm just kind of doing little by little but I'm not seeing any improvements.

 

[dirtboy25]

Right foot delete.

This thing isn't even worth putting your foot down. It's stock, aka gutless.

 

[dirtboy25]

Would I gain any helpful info by doing a contribution test, or buzz test?

I wouldn't think I have injector problems, the truck runs great and idles fine with little to no blowby.

 

[TARM]

I get 22-23 on the highway with my 9K Excursion.

Taking off from a stop as slowly as possible is a huge effect as well as % of stop and go vs highway cruising. Tire size, type, air vs nitrogen, balance, alignment, unit bearings condition, brakes dragging, injector condition (how many miles on the injectors?), transmission or tq converter issues