Places to look for cause of low MPGs
#32
07-18-2011, 09:33 AM
...40 tow w/ John Wood transmission.
#33
07-18-2011, 09:37 AM
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#34
07-18-2011, 11:38 AM
I'm like you with no mods and get 16. I was getting 12 and found my caliper was sticking a little. I just put the sixth caliper on two months ago and the mpg' came back.
#35
07-18-2011, 01:01 PM
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MPG
I was only getting 360 miles out of a 36 gal tank. I have a dp tuner but was running in stock for mpg tests. My truck ran great! I decided to put in a modded 17* HPOP ($275- from clay at riftraft) my first fill up I gained 60 miles on the tank in a 60hp tow setting towing a 20' jet boat through hills. i was amazed!! basicly it added 2 mpg. but i would have never thought a HPOP with only 120,000 miles on it would be and issue. $$$ well spent!
#36
07-18-2011, 01:04 PM
Without sounding too aghast - how in the world can changing the HPOP oil improve fuel mileage? I sucked 3/4 quart out of my reservoir the other day, but only because I was changing from dino to synthetic and wanted a 'full change'. I'm running synthetic for easier winter starts (not mileage). So, 3/4 quart out of 14 quarts? Has anyone shown 'old oil' to significantly affect mileage?
#37
07-18-2011, 01:23 PM
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#38
07-18-2011, 01:26 PM
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#39
07-18-2011, 01:29 PM
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#40
08-18-2011, 09:48 PM
A few things to look at and test.
1. Tire tread pattern. Aggressive tires will normally yield worse mileage.
2. Air intake. I had 5 customers tell me that they all lost 4 mpg after installing the intake. Try putting the stock air box back in.
3. HPOP pressures. Low pressures will prevent optimum atomization.
4. Fuel quality. Make sure you run a good additive.
5. Oil. Good clean oil will help. Remember to always change the HPOP reservoir oil each time.
Jody
1. Tire tread pattern. Aggressive tires will normally yield worse mileage.
2. Air intake. I had 5 customers tell me that they all lost 4 mpg after installing the intake. Try putting the stock air box back in.
3. HPOP pressures. Low pressures will prevent optimum atomization.
4. Fuel quality. Make sure you run a good additive.
5. Oil. Good clean oil will help. Remember to always change the HPOP reservoir oil each time.
Jody
#41
08-18-2011, 09:51 PM
Need a diagnostic tool, whether AE or other, to monitor ICP. Another option is to rig up a line to the heads, with a guage, see David's threads(Bulla) to monitor mechanically, or a HPOP gauge Riffraff Diesel ISSPRO EV2 HPOP Gauge
#43
08-19-2011, 03:56 AM
I posted this somewhere else, thought I'd post it here too..
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: Check out this video. I start out in 2wd but the front driveshaft spins anyway. This was caused by a stuck hub. Service your hubs (30 mins each) and you can fix this. It causes drag on your wheels by turning the entire front drive system.
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.
Check ALL of that and you should get your MPGs back.
http://www.youtube.com/watch?v=XLZI2wMpn5I
2002 F250 4x4 Front Driveshaft (Hubs Stuck) - YouTube
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: Check out this video. I start out in 2wd but the front driveshaft spins anyway. This was caused by a stuck hub. Service your hubs (30 mins each) and you can fix this. It causes drag on your wheels by turning the entire front drive system.
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.
Check ALL of that and you should get your MPGs back.
http://www.youtube.com/watch?v=XLZI2wMpn5I
2002 F250 4x4 Front Driveshaft (Hubs Stuck) - YouTube
#45
10-15-2011, 04:26 AM
Like A/O said. Clogged fuel filter, leaky connections in the fuel line (typically before the fuel pump), air getting in the fuel line, clogged pickup line in the fuel tank can all cause poor MPG. Not enough fuel pressure, ect.
Much of the rest has been covered.
I am also experiencing a loss in fuel economy but I believe it is related to my 15* HPOP getting weak, weak/old maybe slightly clogged injectors (230K).
My fuel PSI has dropped 2 PSI in the past week so I may also have either a fuel filter plugging up or a clogged pickup line or starting to clog pickup line.
I am also running the 6637 which I really want to change to a cold air intake which will pickup air off the top of the hood instead of from inside the engine compartment which would mean more dense air and less heat going into the engine.
Basically my list of to do's to get my HP and mileage back up is....
Replace hood with reverse hood scoop and setup a cold air intake to pull air from on top of the hood.
Replace HPOP with modded 17* HPOP
Replace injectors
drop tank and mod/clean
change fuel filter
clean EBPS tube (already has new sensor)
replace intercooler with a 6.0 intercooler (more dense/cooled air)
replace turbo
This is my todo list but I still have yet to run diagnostics and double check that all other sensors are reading correctly.
Much of the rest has been covered.
I am also experiencing a loss in fuel economy but I believe it is related to my 15* HPOP getting weak, weak/old maybe slightly clogged injectors (230K).
My fuel PSI has dropped 2 PSI in the past week so I may also have either a fuel filter plugging up or a clogged pickup line or starting to clog pickup line.
I am also running the 6637 which I really want to change to a cold air intake which will pickup air off the top of the hood instead of from inside the engine compartment which would mean more dense air and less heat going into the engine.
Basically my list of to do's to get my HP and mileage back up is....
Replace hood with reverse hood scoop and setup a cold air intake to pull air from on top of the hood.
Replace HPOP with modded 17* HPOP
Replace injectors
drop tank and mod/clean
change fuel filter
clean EBPS tube (already has new sensor)
replace intercooler with a 6.0 intercooler (more dense/cooled air)
replace turbo
This is my todo list but I still have yet to run diagnostics and double check that all other sensors are reading correctly.