Jump to content

I'm puzzled about my declining fuel economy. Suggestions?


JohnnyO_71
 Share

Recommended Posts

I have a 2013 SEL. Up until about 8 months ago, I was averaging 5.6L/100km (I'm Canadian...that's about 42 mpg). I was having some misfire trouble, and prior to having the issue properly tended to, my mileage started slipping, from 5.6L/100lm to about 6.1L/100km.

 

Since service was done on the car, here's what I've had done:

 

- all new spark plugs

- all new coil packs

- new air filters

- gas tank cleaned out and fuel lines blown out

- oil change

- tires inflated

 

Still, with all that, I am averaging 6.4L/100km (36 mpg). So I've gone from 42 mpg to 36.

 

And this isn't a colder-weather issue, either.

 

Could it be that my hybrid batteries (since this is a 2013 we're talking about) are losing their mojo and that could be the cause?

Link to comment
Share on other sites

Sorry, I forgot to add that, yes, injectors were all changed too.

 

So, it started with the check engine light coming on, but no rough ride. But the light stayed on. I have a OBD code reader, and it was a misfiring cylinder. That's when I changed the plugs. Light went off, for a day. Then I changed then coil packs. Light went off, for two days, then came back. Meanwhile, there were episodes were I WOULD have a rough ride: always occurred from a cold start. I'd get a block away from home and the car would shake something fierce and the engine light would flash. I'd turn the car off, then back on, and all would be ok, except the solid engine light.

 

I took it to the dealer. They had it for 5 and a half weeks, couldn't figure it out. Finally got a Ford tech on the job, and they figured something got into the fuel line, so that's when they cleaned out the tank and the fuel line. (they also changed out the new plugs I had just put in for new-new plugs). And they put in new injectors. That seems to have solved it.

 

The car has 176,000 km (so about 110K miles).

 

In the time leading up to taking it to the dealer, the milage went from 5.6L/10 km to about 6L/100km, and now after all the work (and the new air filters and oil change), I'm up to 6.4L/100km.

Link to comment
Share on other sites

Could be the car was "off-the 12V battery" for some time and is starting from ground zero.  It has no memory of your previous mpg and driving.  Since the vehicle was in the shop for nearly a month and a half, the weather has changed also contributing to what you are asking.  Furthermore, it you have a code reader, what exactly were the codes?  That can tell a lot.      

 

Link to comment
Share on other sites

On 11/8/2021 at 12:00 AM, Billyk24 said:

Could be the car was "off-the 12V battery" for some time and is starting from ground zero.  It has no memory of your previous mpg and driving. 

 

I was thinking along the same lines, but I've been monitoring mileage after every trip, and long highway rides are still up over 6L/100km each time.

Link to comment
Share on other sites

On 11/8/2021 at 7:19 PM, homestead said:

Decrease from the new tires may have started in April but you may have not have noticed it because of the spring warmup.

Especially if you switched from the Michelin Energy Saver to a tire that has a higher rolling resistance.

Which tires did you install?

 

True. The ones I got are Goodride (*not Goodyear) touring, which are supposed to have low rolling resistance, according this the blurb here: Goodride / WESTLAKE SA07 (quattrotires.com)

Link to comment
Share on other sites

On 11/8/2021 at 8:41 PM, JohnnyO_71 said:

 

225/50R17

2

That's OEM size, which is not found at the link. 225/45 or 225/55.

 

If you're interested, it's easy to measure rolling resistance. All you need is a long level, some shims, and a flat-to-sloping surface. 

- park the car on the flat and roll it forward manually until it just barely stays put

- Lay the level on the ground, and shim the low end until it's exactly level

- measure the length of the level and the thickness of the shim pack. 

Rolling resistance is shim thickness/level length

 

If you have a 1 meter level, expect the shim pack to be 5-15 mm. RR is usually in the 0.005-0.015 range. 

Link to comment
Share on other sites

Since July your mpg's would be going down some now. https://fordcmaxhybridforum.com/topic/5511-how-to-improve-winter-mpgs/?tab=comments#comment-60522

I suspect you would lost 2-4 mi. when changing tires, Michelin Energy Savers get the best MPG's and also worn out tires get better mpg's than new tires. I used 50 psi with Michelins E/S V93 tires which was the max psi. 

BTW  I got 65k-90k miles on a set of tires.

 

Paul

 

Edited by ptjones
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...