Fuel economy

[bwguardian]

So I've run a  tank of gas through the Edge we bought back from our middle daughter.  I've just been running around close to home for now and the MPG calculator on the dash shows 11- 12 mpg.  I just filled it up and hand calculated 9 mpg.  The car has the trailer towing package and I put spark plugs in it when I did the water pump 15k-20k miles ago.  It's also recently had new injectors within the last couple thousand miles... and always passed smog at inspection, but don't know the numbers.  The throttle body looked in decent shape, but I will probably clean it given we bought the car with 93k on the clock and I've not touched it now sitting at 144k on the clock.  

 

One other thing I've always noticed the idle is about 600 rpm with it in gear and maybe 650 rpm in park.  I read somewhere several years back that the cars with the towing packaged were idled down some...maybe to compensate for the radiator cooling fans as they are different.  I'm wondering if the idle can be sped up by 100 rpm or so through a procedure and/or Forscan.  It's kind of annoying when sitting at a light due to the noise it makes at the lower rpm.  I can idle it up a little by barely pressing the gas peddle and the annoying noise goes away.

Edited September 15, 2023 by bwguardian

[DILLARD000]

11 hours ago, bwguardian said:

...tank of gas through the Edge...close to home for now

...dash shows 11- 12 mpg...filled it up and hand calculated 9 mpg

...has the trailer towing package and I put spark plugs in it when I did the water pump 15k-20k miles ago

...recently had new injectors within the last couple thousand miles

...passed smog

...throttle body looked in decent shape, but I will probably clean it given we bought the car with 93k on the clock and I've not touched it now sitting at 144k

...idle is about 600 rpm with it in gear and maybe 650 rpm in park...read somewhere several years back that the cars with the towing packaged were idled down

...wondering if the idle can be sped up by 100 rpm or so through a procedure and/or Forscan

...annoying when sitting at a light due to the noise it makes at the lower rpm...pressing the gas peddle and the annoying noise goes away

Have here a 2008 EdgeAWD V6~3.5L~DOHC; you should be getting ~17mpg local & ~21mpg highway; so something is not proper.

With NonTowPack DualRadiatorFans+FanControlModule & single Fuse;

believe actual Fans+Motors are the same as the TowPack, but TowPack has a dual output FanControlModule\FCM & dual Fuses.

ThrottleBody does have an IdleAdjustment screw; note that if its changed too much, a TroubleCode will be generated, so make note of its original\factory position.  Haven't found a Forscan method of changing the idle, but that may be possible.

Glad to hear you've already PM'd that notorious InternalChainDriven WaterPump; mine failed at about 150kMiles to the external outlet behind the Alternator last year;  had whole Engin+Trans assembly out of vehicle to change WaterPump, along with new TimingSet & upgrade to  HiVolOilPump.

Also added traditional MultiStageTempSwitch controls for Fans, wired parallel to FCM, maintains Fan ops & 192~198f Engin cooling if notorious FCM ever fails again.

If yours is AWD, be sure to service the PTU & RDU with some fresh quality GearOil.

Edited September 16, 2023 by DILLARD000

[dabangsta]

Throttle body does not have an idle adjustment! It is a stop, and if it is improperly adjusted, could result in the throttle blade either not able to open, or not able close. I wouldn't touch it. The idle is completely controlled by the PCM and metered air. It doesn't make sense that the idle would be lower for a tow package equipped vehicle.

 

9 mpg is really bad. The EPA rating for FWD is 16 city, 24 highway, 19 combined. AWD is 15 city, 22 highway, 18 combined.

 

My AWD 3.5 powered vehicle gets driven hard and on surface streets only (1 mile at 65 mph) and I get within 1 mpg of the EPA rating for it (which is 18 mpg city, it is a 2012 Fusion Sport AWD). Every stop light is like a 1/4 drag (up to the speed limit of course), I don't coast very often, I manually hold lower gears so I frequently am cruising at 3500-4500 rpm. I might not do as many very short (3-4 miles) trips, most are 15-25 or more, I don't idle after startup waiting for the AC to cool it off, I just go.

[DILLARD000]

@dabangsta

Ok, guess I'll need to start driving like that.   So your ThrottleBody also only has 2 positions, fully closed or fully opened? 

Edited September 16, 2023 by DILLARD000

[bwguardian]

I read somewhere the tow package cars idled lower when we first got the car because it really needs more rpm when at a stop light.  I'm wondering if the two...bad mileage and low idle...are connected.  That leans me towards dirty throttle body, but it didn't look that bad when I did the water pump back when...may need to take another closer look, took a peek when doing the OSS  TSS.  I guess it could also be 02 sensors or map sensor, but I'd think that would throw a code.  I'll also check accuracy of odometer given mpg calculator is showing more than hand calculated.

[DILLARD000]

Yep, cleaning the Intake, Throttle, MAF can never hurt.  How old are Plugs and OxSensors, should be renewed every 100kMiles or 12yrs.

Oh, you did note above you'd changed the plugs ~15kMiles ago; may want to pull those & inspect anyway for color & proper gap.

OxSensors will bias the Air/Fuel mix as they age to the rich end of the curve gradually until they finally cause a TroubleCode,

 

Edited September 16, 2023 by DILLARD000

[dabangsta]

1 hour ago, DILLARD000 said:

@dabangsta

Ok, guess I'll need to start driving like that.   So your ThrottleBody also only has 2 positions, fully closed or fully opened? 

Yes, my vehicles generally only have idle and WOT. But that is just the way I drive. The throttle plate really never fully closes, and the actuator controls the idle speed.

 

I don't see how fiddling with the throttle stop would do anything but cause an uncontrollable too high idle or the throttle blade to close to tight that the electronic actuator cannot open it. I am not even real sure that is an actual mechanical stop, that bolt that goes into the actuator.

[bwguardian]

The O2 sensors are originals as far as I know...seems like there would be a way to test them.  Maybe at the least they should be pulled and cleaned.  I always thought the map sensor was either good or bad and couldn't be cleaned...but I'm only familiar with diesels and old school carburetor engines.  The throttle body is easy enough to get to so I'll take a closer look.  I did notice yesterday afternoon when cruising 50 mph for a mile or so I reset the mpg on the dash and it went up to around 19 mpg before I came up to a stop light. 

[DILLARD000]

On 9/17/2023 at 9:35 AM, bwguardian said:

...O2 sensors are originals as far as I know...seems like there would be a way to test them.  Maybe at the least they should be pulled and cleaned

...thought the map sensor was either good or bad and couldn't be cleaned

...throttle body is easy enough

...cruising 50 mph for a mile or so I reset the mpg on the dash and it went up to around 19 mpg before I came up to a stop light

* OxSensors can't really be cleaned, their chemical\reactive coating gradually wears off & slowly will enrich fuel\air mix & cause lower MPGs; defintely replace if >100kMiles\12yo.  An OBD2 Scanner can monitor OxSensor signals:  once engine+exhaust are at full operating temp, both UpStream OxSensors should alternate 0.1v~0.9v, both DnStream should be relatively steady >0.6v.

* MAFSensor definitely can be cleaned; do NOT use Carb\ThrottleCleaner or BrakeCleaner, much to harsh; use MAFCleaner\ElectricalCleaner\RubbingAlcohol & QTips.

* Best to ignore & not use the "Instantaneous MPG" setting in the InstrumentCluster, it inherently jumps around; best to use the "Averaged MPG" setting.

 

Edited September 19, 2023 by DILLARD000

[DILLARD000]

PS:

As OxSensors age & wear out, again they inherently enrich the Fuel/Air mix, causing lower MPGs;

this overly rich mixture also results in overly rich exhaust, causing CatCons to run hotter & wear out sooner, an expensive & avoidable repair.

A Bosch 15719 with 24i00 0m610 Long Cable+Plug is good to replace any Ford 4WireNarrowBand Sensor.

[bwguardian]

I pulled and cleaned the throttle body...it was dirty, but not too bad...and maf sensor, which still looked newish.  I know in the 6 years and 50k miles since we've had it this has not been done.  It seemed to might of helped a little, but still idle around 625-650 rpm, and the "growling" at a stop light is still present.  Next step is to look at the upstream O2 sensors via Forscan and see what's going on with them.  Mileage seems to be up by 3 or so mpg as I've been driving the car more and not sitting idling waiting on our daughter to get out of school for 10- 15 minutes...probably need to get some highway driving in and see...

[Cerberus]

On 9/20/2023 at 5:27 PM, bwguardian said:

I pulled and cleaned the throttle body...it was dirty, but not too bad...and maf sensor, which still looked newish.  I know in the 6 years and 50k miles since we've had it this has not been done.  It seemed to might of helped a little, but still idle around 625-650 rpm, and the "growling" at a stop light is still present.  Next step is to look at the upstream O2 sensors via Forscan and see what's going on with them.  Mileage seems to be up by 3 or so mpg as I've been driving the car more and not sitting idling waiting on our daughter to get out of school for 10- 15 minutes...probably need to get some highway driving in and see...

Try a high quality fuel system cleaner. I like BG44k.

Dirty or sticky injectors can cause all kinds of symptoms that are difficult to trace

it is likely that your O2 sensors are age skewed as dillard said. impossible to test for this, because it reads as if it knows what it is talking about but the input (exhaust) can actually be much richer than the output (voltage) indicates. 

and, if you're going to change your upstream sensors, running the fuel system cleaner through it before hand is advisable as opposed to after. 

[bwguardian]

On 9/26/2023 at 3:32 AM, Cerberus said:

Try a high quality fuel system cleaner. I like BG44k.

Dirty or sticky injectors can cause all kinds of symptoms that are difficult to trace

it is likely that your O2 sensors are age skewed as dillard said. impossible to test for this, because it reads as if it knows what it is talking about but the input (exhaust) can actually be much richer than the output (voltage) indicates. 

and, if you're going to change your upstream sensors, running the fuel system cleaner through it before hand is advisable as opposed to after. 

The injectors are new as stated in my initial post.  I filled up again yesterday and hand calculated 13.3 mpg and the avg mpg on the dash is showing 15-16 so driving it more as opposed to sitting idle waiting for our daughter to get out of school for 10-15 minutes makes a difference.  I will be hooking up Forscan and taking a look as now a new issue has popped up as of yesterday. 

 

We left for church yesterday morning for the short drive to/from church and everything seemed fine.  We go to pick up our daughter an hour or two later and notice the a/c is not getting cold.  When back at the house both cooling fans are running and the a/c clutch is engaging when turned on and disengaging when turned off, but the refrigerant lines under the hood are warm not cold.  This morning the car is cold after sitting the night I start car and neither cooling fan is running.  I turn on the a/c and the clutch doesn't engage nor do the cooling fans come on.  This car has the towing package so I am understanding one fan should come on when the car is cold and the a/c is turned on as stated in the following thread by autom8r about midway down.  The a/c has been working fine prior, it just seems like all of a sudden it's on the blink which is why I'm leaning towards the cooling fans or possibly a pressure switch, but I will put the a/c gauges on it to see what pressure readings I get.

 

[DILLARD000]

3 hours ago, bwguardian said:

...injectors are new

...filled up...calculated 13.3 mpg...avg mpg on the dash is showing 15-16

...driving it more as opposed to sitting idle waiting for our daughter to get out of school for 10-15 minutes makes a difference.

...will be hooking up Forscan and taking a look as now a new issue

...yesterday morning for the short drive...fine...hour or two later and notice the a/c is not getting cold

...back at the house both cooling fans are running and the a/c clutch is engaging when turned on and disengaging when turned off

...refrigerant lines under the hood are warm not cold

...This morning the car is cold after sitting the night I start car and neither cooling fan is running

...turn on the a/c and the clutch doesn't engage nor do the cooling fans come on

...towing package so I am understanding one fan should come on when the car is cold and the a/c is turned on

...a/c has been working fine prior

...leaning towards the cooling fans or possibly a pressure switch, but I will put the a/c gauges on it to see what pressure readings

The Radiator FanControlModule\FCM, mounted on the upper left corner of the FanCowling, is a common NotoriousFailureItem\NFI;

your TowPack should have the DualOutput FCM, instead of the SingleOutput FCM version on NoTowPack V6~3.5L~DOHC Engines.

Best to avoid non~FordMotorCraft replacements for the FCM;

they're definitely cheaper than OEM but most are not fully compatible with the Ford PCM & PulseWidthModulated GroundLeg circuitry.

Edited October 2, 2023 by DILLARD000

[Haz]

Trailer Tow Package cooling fan power is protected by two 40-amp fuses in the underhood Battery Junction Box (BJB), indicated by red arrows and red outlining in the following photo...

 

 

Good luck!

 

[bwguardian]

Hooked up Forscan and no codes related to a/c so did the KOEO test and fans powered up then compressor clutch engaged.  I hooked up a/c gauges and both high and low side are near 0.  Strange part is when I remove the compressor clutch relay and insert a jumper wire to engage the clutch while the engine is running I get a low side pressure of -20 and a high side pressure of +20.  Not sure what to think about this...