MPG's keep dropping!
Thread Starter
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Senior User
Joined: Jun 2010
Posts: 137
Likes: 0
From: Atlanta, Georgia
MPG's keep dropping!
My past few fill-ups I have hand calculated my MPG's at 12.5! I usually get 18 mpg, and about 20 on the highway. I have a Superchips tuner with the mileage xs tune installed. On top of it I have also been losing oil rather quickly, and I have no visible leaks. I replaced the ebp tube and sensor, and checked the shaft play on the turbo (there is none to speak of). I did a couple of searches, but wasn't able to find anything that looked similar. Any ideas as to what the problem might be?
Cargo Master
Joined: Jun 2003
Posts: 3,292
Likes: 6
From: Ardenvoir, Washington
Here is some threads that might help you troubleshoot your problem:
https://www.ford-trucks.com/forums/1...l-rapidly.html
https://www.ford-trucks.com/forums/1...fuel-bowl.html
The following thread is active right now.. keep checking for updates:
https://www.ford-trucks.com/forums/1...major-oil.html
https://www.ford-trucks.com/forums/1...l-rapidly.html
https://www.ford-trucks.com/forums/1...fuel-bowl.html
The following thread is active right now.. keep checking for updates:
https://www.ford-trucks.com/forums/1...major-oil.html
Thread Starter
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Senior User
Joined: Jun 2010
Posts: 137
Likes: 0
From: Atlanta, Georgia
Thanks for the links, but my oil loss isn't as bad as those. It is more of the mpg loss that has me worried. I checked my 'y' pipe, right there at the turbo, and there is no oil in either of the pipes. I have also checked the fuel filter bowl for oil (with the drain ****), and there is none. I am going to check for soot at the bellows... I will report back soon.
Oh, and there are no codes being thrown.
Oh, and there are no codes being thrown.
Hotshot
Joined: Nov 2008
Posts: 15,014
Likes: 35
From: Semper Fi tell I die!
My past few fill-ups I have hand calculated my MPG's at 12.5! I usually get 18 mpg, and about 20 on the highway. I have a Superchips tuner with the mileage xs tune installed. On top of it I have also been losing oil rather quickly, and I have no visible leaks. I replaced the ebp tube and sensor, and checked the shaft play on the turbo (there is none to speak of). I did a couple of searches, but wasn't able to find anything that looked similar. Any ideas as to what the problem might be?
wow 12.5 good in winter
but anyhow hows your wheel bearings, brakes, differential fluids and transfercase fluid? this stuff could create drag, along with yoru tire pressure, is it to low?
Senior User
Joined: Oct 2010
Posts: 407
Likes: 2
From: Mobile, AL
You joined in June, so is this your first winter? Winter blend can lower mpg 1-1.5 but not 10. Where do you live? Cold, yet?
Oil pressure is paramount to the injectors, so if you're losing oil that may affect the mpg. You need to figure out where that oil is going. What is your loss rate? 1 qt a week? A gallon a day?
What does your coolant look like, color/quantity? Any smoke on start? Rough running/idle? Need more info, but I think you had better get a handle on the oil problem first. That may fix your mpg.
Oil pressure is paramount to the injectors, so if you're losing oil that may affect the mpg. You need to figure out where that oil is going. What is your loss rate? 1 qt a week? A gallon a day?
What does your coolant look like, color/quantity? Any smoke on start? Rough running/idle? Need more info, but I think you had better get a handle on the oil problem first. That may fix your mpg.
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Thread Starter
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Senior User
Joined: Jun 2010
Posts: 137
Likes: 0
From: Atlanta, Georgia
You joined in June, so is this your first winter? Winter blend can lower mpg 1-1.5 but not 10. Where do you live? Cold, yet?
Oil pressure is paramount to the injectors, so if you're losing oil that may affect the mpg. You need to figure out where that oil is going. What is your loss rate? 1 qt a week? A gallon a day?
What does your coolant look like, color/quantity? Any smoke on start? Rough running/idle? Need more info, but I think you had better get a handle on the oil problem first. That may fix your mpg.
Oil pressure is paramount to the injectors, so if you're losing oil that may affect the mpg. You need to figure out where that oil is going. What is your loss rate? 1 qt a week? A gallon a day?
What does your coolant look like, color/quantity? Any smoke on start? Rough running/idle? Need more info, but I think you had better get a handle on the oil problem first. That may fix your mpg.
My oil loss was about 1 quart every fill-up, so every 300 or so miles, and I don't see any puddles or parts covered in oil.
Coolant is within an acceptable range, still green. A little bit of white smoke on start-up since I unplugged the fuel bowl heater, (it shorted out, and I haven't had a chance to replace it yet).
Any other info you need? Please ask! The truck has 234,000 miles. I am coming up on an oil change in about 500 miles. First time around I put in Rotella 15W-40, and changed the fuel filter, also at that time I replaced the O-rings to the HPOP.
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Senior User
Joined: Oct 2010
Posts: 407
Likes: 2
From: Mobile, AL
Recap- 7.3 PSD, 234k, mpg drop from 18 to 13, minor oil loss of 1qt per 300 miles w/no visible leaks. No oil in the fuel, tail pipe, coolant, etc. No oil in the valley or on the engine and turbo/pipes look good and no soot. You've checked all the drag producers (brakes, tans fluids, tire pressure).
I'm still thinking your oil loss and mpg drop are related. If the HPOP and pedestal o-rings are tight (they will shrink and leak when cold), then the injector o-rings may be going south. I don't think there is a test for that, but it would be odd for them to fail so suddenly for the mpg drop.
Do you plug in at night? Do you do short runs? Does the engine have time to warm-up and run before shutting down?
I've noticed a pretty similar mpg drop since it got "cold" here. When I leave in the AM it has been in the teens or low twenties and the motor barely has time to get warm before I shut it down at the commuter lot 12 miles later. Same for the drive home. I haven't noticed an oil loss, though.
I'm still thinking your oil loss and mpg drop are related. If the HPOP and pedestal o-rings are tight (they will shrink and leak when cold), then the injector o-rings may be going south. I don't think there is a test for that, but it would be odd for them to fail so suddenly for the mpg drop.
Do you plug in at night? Do you do short runs? Does the engine have time to warm-up and run before shutting down?
I've noticed a pretty similar mpg drop since it got "cold" here. When I leave in the AM it has been in the teens or low twenties and the motor barely has time to get warm before I shut it down at the commuter lot 12 miles later. Same for the drive home. I haven't noticed an oil loss, though.
Freshman User
Joined: Aug 2006
Posts: 49
Likes: 0
Mine did the same thing about a year ago. Then the oil loss kept getting worse. It ended up being one injector o-ring, I replaced all of the injector o-rings and glow plugs last winter and mpg went back to normal and oil loss stopped.
Thread Starter
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Senior User
Joined: Jun 2010
Posts: 137
Likes: 0
From: Atlanta, Georgia
Recap- 7.3 PSD, 234k, mpg drop from 18 to 13, minor oil loss of 1qt per 300 miles w/no visible leaks. No oil in the fuel, tail pipe, coolant, etc. No oil in the valley or on the engine and turbo/pipes look good and no soot. You've checked all the drag producers (brakes, tans fluids, tire pressure).
I'm still thinking your oil loss and mpg drop are related. If the HPOP and pedestal o-rings are tight (they will shrink and leak when cold), then the injector o-rings may be going south. I don't think there is a test for that, but it would be odd for them to fail so suddenly for the mpg drop.
Do you plug in at night? Do you do short runs? Does the engine have time to warm-up and run before shutting down?
I've noticed a pretty similar mpg drop since it got "cold" here. When I leave in the AM it has been in the teens or low twenties and the motor barely has time to get warm before I shut it down at the commuter lot 12 miles later. Same for the drive home. I haven't noticed an oil loss, though.
I'm still thinking your oil loss and mpg drop are related. If the HPOP and pedestal o-rings are tight (they will shrink and leak when cold), then the injector o-rings may be going south. I don't think there is a test for that, but it would be odd for them to fail so suddenly for the mpg drop.
Do you plug in at night? Do you do short runs? Does the engine have time to warm-up and run before shutting down?
I've noticed a pretty similar mpg drop since it got "cold" here. When I leave in the AM it has been in the teens or low twenties and the motor barely has time to get warm before I shut it down at the commuter lot 12 miles later. Same for the drive home. I haven't noticed an oil loss, though.
I do plug it in at night, so long as the temp is to drop below 40*. And I mostly do short runs where the motor barely warms up.
