(UK) Help me diagnose poor MPG Please. MK 3.5 Focus 1.5 TDCI 120ps Zetec: Highway/Motorway is 53PMG (Around 500miles to the tank driving on average 65mph)

Hey, I've had the car for 18 months buts its always been poor on fuel.

• 83000 Miles FSH
• Fully serviced, recommended oil and filters installed (engine runs sweet; quite, smooth and powerful)
• Serviced on time
• New OEM Thermostat and Housing (holds 91+c on warms days and around 80-85c when its cold/icy), no issues with warm up etc
• New battery
• Correct tyre pressures etc
• Premium diesel used (not super but not supermarket fuel)

I've considered it could be the tyres, its on Pirellis, i have bought Goodyear Efficiency Performance Grip 2 (due to be installed soon)

I drive to the speed limit, no aggressive accelerating and usually break early.

So, what could be the issue? I've considered three things:

The Sync 2 has been upgraded to Sync 3: could this be draining more battery? Hence more alternator use and subsequently more fuel use?

AC makes a noise when on, i think from the compressor. Its not super cold but works and gets rids of the condensation on the windows. But I've not known the fan to come on when the AC is on.

ECU Mapping issue. Maybe its been remapped before i bought it. i was also thinking it need updating amending because ive heard about new Mark 3.5 owners, when it was new taking it back to ford for poor MPG and ford providing a ECU update.

Any help welcome.

Thank You

44 minutes ago, Habib1985 said:

The Sync 2 has been upgraded to Sync 3: could this be draining more battery? Hence more alternator use and subsequently more fuel use?

I doubt it, no

 

44 minutes ago, Habib1985 said:

AC makes a noise when on, i think from the compressor. Its not super cold but works and gets rids of the condensation on the windows.

If it needs re gassing then that can cause a bit of drag

 

47 minutes ago, Habib1985 said:

But I've not known the fan to come on when the AC is on.

That's normal

 

48 minutes ago, Habib1985 said:

ECU Mapping issue. Maybe its been remapped before i bought it.

If it was remapped it would be better on fuel

 

48 minutes ago, Habib1985 said:

need updating amending because ive heard about new Mark 3.5 owners, when it was new taking it back to ford for poor MPG and ford providing a ECU update.

Checking for and updating the PCM software certainly won't hurt.

 

You're not too far off though to be fair, I used to average 53MPG on my 2016 1.5 TDCi until I had it remapped, then it averaged 59MPG, so you're not far off.

Change the oil every 6,000 miles as regen contaminates it

.

1 hour ago, DaveT70 said:

I doubt it, no

 

If it needs re gassing then that can cause a bit of drag

 

That's normal

 

If it was remapped it would be better on fuel

 

Checking for and updating the PCM software certainly won't hurt.

 

You're not too far off though to be fair, I used to average 53MPG on my 2016 1.5 TDCi until I had it remapped, then it averaged 59MPG, so you're not far off.

Change the oil every 6,000 miles as regen contaminates it

Thank you for the reply mate.

Any suggestions on who can remap it? i am based in Manchester. 

Superchips, Remap Kings or Celtic tuning