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Starting to troubleshoot the change in my Ecoboost fuel economy, any input is appreciated!
As you can see, this winter my fuel economy has dropped significantly compared to the last two winters. The circles are towing events, disregard those. The vertical red lines indicate winter fuel blends arriving in Iowa each fall.
What's the same:
1. Fuel - I buy 80% of my gas from the same station, E-10 fuel.
2. Driving habits - I tend to drive 0-5 over with cruise control. Lots of my miles are highway. 90%+
3. Vehicle setup - Haven't added or changed anything like programmers, etc..
What is different since last winter:
1. New plugs, gapped to 0.31"
2. New air cleaner at 60k miles
3. New tires at 70k (Wrangler Adventures, were SR-A's previously)
4. Firestone airbags on rear, but normally they are only at a few psi, so no real change in ride height
5. New upstream O2 sensor at 70k miles
Weather was much colder last year vs. this year, so I've also ruled that out. I'm putting about 1,000 miles/week on right now, so I'm collecting lots of data points.
What else should I be looking at?
To do a comparison, my friend has a 2010 5.4L SCrew I've benchmarked against several times. Normally any time of the year, I am 1.4-1.7 mpg higher than his truck, which has 3.31 gears. Yesterday we caravanned from Minneapolis to Ames, IA (220 miles) at 70mph on cruise. He got 16.8, I got 16.4mpg, which is essentially the unexplained 2 mpg reduction.
Potential causes:
1. Tires
2. Bad luck with head winds (its been very windy this winter) - My road trip check against my friend's truck should eliminate this as a potential cause
3. Engine losses
4. Drivetrain losses
5. ???
starting to troubleshoot the change in my ecoboost fuel economy, any input is appreciated!
as you can see, this winter my fuel economy has dropped significantly compared to the last two winters. The circles are towing events, disregard those. The vertical red lines indicate winter fuel blends arriving in iowa each fall.
What's the same:
1. Fuel - i buy 80% of my gas from the same station, e-10 fuel.
2. Driving habits - i tend to drive 0-5 over with cruise control. Lots of my miles are highway. 90%+
3. Vehicle setup - haven't added or changed anything like programmers, etc..
What is different since last winter:
1. New plugs, gapped to 0.31"
2. New air cleaner at 60k miles
3. New tires at 70k (wrangler adventures, were sr-a's previously)
4. Firestone airbags on rear, but normally they are only at a few psi, so no real change in ride height
5. New upstream o2 sensor at 70k miles
weather was much colder last year vs. This year, so i've also ruled that out. I'm putting about 1,000 miles/week on right now, so i'm collecting lots of data points.
What else should i be looking at?
To do a comparison, my friend has a 2010 5.4l screw i've benchmarked against several times. Normally any time of the year, i am 1.4-1.7 mpg higher than his truck, which has 3.31 gears. Yesterday we caravanned from minneapolis to ames, ia (220 miles) at 70mph on cruise. He got 16.8, i got 16.4mpg, which is essentially the unexplained 2 mpg reduction.
Potential causes:
1. Tires
2. Bad luck with head winds (its been very windy this winter) - my road trip check against my friend's truck should eliminate this as a potential cause
3. Engine losses
4. Drivetrain losses
5. Fuel reformulation ( different supplier, lower btu content )
6. Simple Age
7. The oft-discussed eb/di intake carbon issue
8. Cac needs cleaning
9. Brakes ( pad skew, dragging, etc)
10. Cats (starting to plug up)
11.
12.
13.
- andy
You mentioned new tires, can you see on your chart where the tires were changed? What is the weight difference between the two? That can account for a good part of the drop if they line up. Also, is your MAF/Temp sensor dirty? That can cause false readings which could make it run rich.
You mentioned new tires, can you see on your chart where the tires were changed? What is the weight difference between the two? That can account for a good part of the drop if they line up. Also, is your MAF/Temp sensor dirty? That can cause false readings which could make it run rich.
EB's use a MAF? I thought it was a MAP. Got whacked on that one a while back
Good point though - trackng A/F's over time (these trucks use widebands up front now).
True, the EB doesn't use a true MAF. (I was thinking IAT but typed MAF, my bad) There are two temp sensors that could get gunked up and cause a false reading. The best way to check this would be to check the fuel trims, that would tell you in a hurry if too much fuel is being dumped into the engine.
Here's a list of sensors that are used on the different engines. I found this at "that other site" where someone had copied the Ford shop manual.
• Camshaft Position (CMP) Sensor
• Catalyst Monitor Sensor (CMS)
• Crankshaft Position (CKP) Sensor
• Cylinder Head Temperature (CHT) Sensor
• Fuel Rail Pressure (FRP) Sensor — 3.5L Gasoline Turbocharged Direct Injection (GTDI)
• Heated Oxygen Sensor (HO2S)
• Intake Air Temperature (IAT) Sensor — 3.5L GTDI
• Knock Sensor (KS)
• Manifold Absolute Pressure (MAP)/Intake Air Temperature 2 (IAT2) Sensor — 3.5L GTDI
• Mass Air Flow (MAF) Sensor — 3.7L, 5.0L (4V) and 6.2L (2V)
• PCM
• Turbocharger Boost Pressure (TCBP)/Charge Air Cooler (CAC) Sensor — 3.5L GTDI
• Variable Camshaft Timing (VCT) Oil Control Valve — 3.5L GTDI and 3.7L
• VCT Variable Force Solenoid — 5.0L (4V) and 6.2L (2V)
EDIT: there also seems to be some differences in how Ford named the parts on the 2011 vs 2012+. I have seen where the IAT is called a MAF in some parts catalogs even though it isn't. No matter what it's called, if the sensor is wearing a fur coat the readings could be off.
EDIT X2: It seems that early 2011s did actually use a MAF sensor but only the temp side of it. There was a location and part number change along the way. If the sensor is on the side of the air filter housing it is a MAF type sensor. If it's on the top of the housing then it is an IAT sensor. The rumor I read was there was a delay in issuing the new patent for the IAT so the older MAF was used in the interim period.
Good homework assignments, I'll start collecting more data on the engine.
OE tires are 39lbs, my new tires are 53 lbs. Certainly could be a factor, but since I'm doing 90% plus steady state driving, I can't buy into the notion that 2mpg came from the tire change. If I was doing lots of start/stops, different story of course...
I think you possibly could lose 2 mpg to higher rolling resistance. The OE tires are chosen for minimum rolling resistance as it makes a difference in the EPA numbers.
It's also possible you are getting more ethanol this winter than last. You are in Iowa which still has ethanol-free 87 available, I'd consider running a few tanks of that when you can find it. Clue: If you go to a gas station and 89 is cheaper than 87, the 87 is pure gas.
The emergency brake could be sticking. Attached is a link to a video of the ebrake mechanism being cleaned and lubed with anti-seize. This probably is not your problem since your truck is fairly new but it is in Iowa where it snows.
I'd bet your tires are causing a while lot of the problem, 14 pounds a tire is nothing to sneeze at! That works out to 56 additional pounds of rotational mass. If they're taller it's even worse because the weight is further out. If they wider you also picked up wind resistance too. There's a good reason the factory only puts P metric tires on the F150. An XL rated tire has a higher weight limit than your axles do, anything more is a waste.
I went from the stock 265/60/18 tires to a 275/65/18 tire and since then i have lost around 1.5 to 2mpg.
With the stock tires i could knock off 20 to 22mpg most anytime and around 18 to 19 around town and my lifetime average with the first 30,000 miles was 18.1 mpg
With the new tires the mpg has fallen to around 16 city and 19 to 20 IF i'm lucky on the highway. In 18,000 miles the lifetime average has fallen to 17.4 mpg.
Also with the new tires a headwind REALLY kills me now, where as with the stock tires it effected it but not near as much.
Yes i have corrected my speedometer with the upgraded tire size.
I went from the stock 265/60/18 tires to a 275/65/18 tire and since then i have lost around 1.5 to 2mpg.
With the stock tires i could knock off 20 to 22mpg most anytime and around 18 to 19 around town and my lifetime average with the first 30,000 miles was 18.1 mpg
With the new tires the mpg has fallen to around 16 city and 19 to 20 IF i'm lucky on the highway. In 18,000 miles the lifetime average has fallen to 17.4 mpg.
Also with the new tires a headwind REALLY kills me now, where as with the stock tires it effected it but not near as much.
Yes i have corrected my speedometer with the upgraded tire size.
Sorry - dint mean to put yall through a search - thought ye might have had that info on-hand already
Significant difference, eh? Dem froggy tahrs sure be light fer a truck tahr ....
Thankee!
MGD
I wanted to know myself so I put a email into Cooper just to see if that was right, They only make it for Discount Tire so there isn't much info on the them, The weight i found was from a ebay listing for the same tires, so it may not be right
Found the tire weight for the Michelin on Tire Rack.. Im sure there is a chance that the oem's may even weigh a little less.
Will update my original post if its not right when i get the email back from Cooper.
Last edited by KingRanchCoy; 01-20-2015 at 10:33 AM.
01-16-2015, 03:47 PM
