My 2011 F150 XL with 3.5L ecoboost has 220,000 miles and is getting poor fuel mileage after some service work. Engine code said that catalytic converter on drivers side needed to be changed. That was done. Then a 'whistling' sound coming from thie connection. Now, when towing 2,000 lb lawcare trailer the fuel mileage is horrible.

Changed the spark plugs, ignition coils also. Anyone have ideas on why the por fuel mileage after the work is performed?

 

220K????

I think you may be the leader on the forums with that mileage!

Care to share what problems if any has happened in those miles?

As far as your specific question does the truck still have the power it is suppose to have? Sounds like you may have a boost leak somewhere. Im sure Wookie and a few others will pop in and help out on this.

 

What are you considering "poor mileage"?

220,000 miles on an Ecoboost is awesome if you haven't had any other "major" issues IMO..

More info needed for sure..

I get 10-11 mpg towing my #5000 TT and think that's just fine..

I get 16-17 mpg on my daily commute to work and that's just fine too.

I get 20-21 mpg on straight hwy mpg and that's just fine too..

Good luck!

Mitch

 

Here's my $.02.

The whistle makes me believe that whoever worked on it left a connection loose on the pressure or inlet side of the turbo plumbing. This will generate a boost leak. Give it a good looking over and see if anything is loose or wrong. In the Audi world it's common to make a pressure tester from a correct sized plumbing cap and an air compressor. The MAF is disconnected and the cap is installed in the air inlet. An air chuck is glued onto the cap an low (10 psi) or so air is pumped into the intake. This will let you hear the leak with the engine off. The PCV ports will need to be disconnected and plugged so you don't pressurize the crankcase and blow oil everywhere. Read all about this in the B5 S4 section of Audizene, those guys have made it an art form.

Is your truck throwing a CEL? What did the guy that work on it say?

Was it throwing a CEL when you took it in? A bad cat will throw a cat efficiency code in most cases. Take it to a parts barn and have them read it. Not all codes will trigger the light.

 

thanks for all the comments. The mileage on the last tank was 11.2mpg pulling the landscape ttrailer. My son in law is using the truck and today I was with him. He put the cat on after ford shop said that the cat bad. The 'whistling' sound is coming from the cat. There are no flange gaskets from ford for this ecoboost. And the flange bolts are tighten with an impact but after some driving time they will work loose and not be very tight hence the whistling. Also when the bolts ae re-tightened the noise leaves and fuel mileage gets better to 15mpg. Also today, aswe started the truck ran good, but as the day progressed, the idlling of the truck got rougher. There is also alot of soot at the tailpipe when I an my finger on the inside of the pipe. vehicle idles at work sites for 15-20 minutes. Seems to me that idling could be issue, but son in lawsays starting engine 15-20 times a day uses more fuel. What do you guys think? thanks again for your ideason the issue. This has been a good truck and this is 1st major issue.

 

After 220k, you probably have carbon deposits all over the valves and combustion chambers. This is an issue with direct injection engines.

 

Carbon issues may be the problem, but a sooty exhaust pipe is completely normal with a D/I Engine. What i would recommend is unhooking the trailer, get on a back road and give the truck some hard wide open runs.. I will almost guarantee you will see some black smoke coming out of the exhaust at first. These engine like to be run hard, and if you baby them around they start to run a little rough.

I would also recommend using top tier gasoline like Shell for a few tanks along with some Techron cleaner. You can buy it at walmart and it will also start running better.

 

Well, if you are including your mpg's off of idling for 15-20 minutes at a time, several times a day, I think you are doing good getting 11 mpg...

Stopping and starting 15-20 times a day will use a lot LESS gas than letting it just sit there and idle..

That's why the new 2.7 has an auto shut off feature when you come to a stop and will auto start when you hit the gas pedal.. All for better mpg's..

Anyway, good luck with it.

Mitch

 

With the idle times you posted, that means your truck is sitting doing nothing, but burning gas for anywhere from 3.75-6.5 hours per day. Add that to pulling a trailer filled with landscaping equipment and I'd be happy getting 11-12 mpg. One estimate I've heard is idling is equivalent to drive at 35 mph. If you're idling for that length of time it's like you're driving anywhere from 131-227 miles per day without it adding to your odometer.

I've heard the claim that starting and stopping your engine burns more fuel than letting it idle, but the last time I heard that claim everyone was running carburetors. In my completely uninformed opinion the claim was probably started when someone figured out that the gas in a carburetor evaporated over night (requiring you to pump the gas a few time when starting) and when the engine was hot so they made the claim that it is always more efficient to let your engine run. A fuel injected engine is pretty much a close loop so the gas really can't evaporate, which explains why you don't have to pump the gas to get them to start.

 

Ask him if that's the case, why did Ford put the stop/start technology in the 2.7?

Answer: Because it improves the gas mileage, otherwise they wouldn't spend the $$$ to develop and implement that technology.

 

In lieu, find some "cleaner" that says, add X amount every 4000 mi, and add 1/10th of that every 400, a tankful....give or take.