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Discussion Starter · #1 ·
Hi

I've recently purchased a 335d e91 that's about 10 years old with 130k. Before buying I'd read it's possible to get up to 40mpg. I'm doing a lot of motorway miles with some in town driving at the end. I'm getting about 32mpg currently without booting it.

There's a bit of a hot oily smell when having a short cane but not when driving normally. The engine and gearbox have been serviced frequently and everything else done.

Can't anyone give any pointers as to the low mpg or this to be expected for this engine.

Cheers
 

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Discussion Starter · #3 ·
Yeah even after resetting the trip on only motorway it'll go max 34. Would using something to clean the engine as an additive work. Or could it be the turbo vaccuum hoses not allowing the turbos spool up and making the engine less efficient.
 

· Pedant and Curmudgeon
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Carbon Build Up (CBU) usually has effects beyond bad mileage: misfires and rough running/idling.

Have the swirl flaps been removed? (on EU 35d engines, it's often done to prevent them from failing and trashing the engine). Removing them will almost certainly reduce mileage.

Is the DPF plugged? Need to read the pre-and-post DPF pressure points with a scanner.

Is the DOC Catalyst plugged? Similar to DPF.

Is the EGR valve stuck open or shut?

Also, what speed are you travelling on the M-Way? 80 mph will drop 2-4 mpg from 60 mph (which is almost the "best" speed - IME 55mph is best.)

Also, folks, when posting please specify US gallons or UK gallons (and mpg), as there is a significant difference. The OP is in UK, and his 40 mpg is about our 35 or so.
 

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Discussion Starter · #5 ·
Yeah sorry about that, I knew there was a difference between the US and UK gallon but didn't think to specify in this forum. Going on that basis my max of 34mpg is equivalent to your 29 approximately. This is sat at 80, but I've found 90 with is only very slightly higher on the rev counter is pretty much the same.

In answer to the other questions I'd say no as everything on the car is standard and doesn't seem to have been messed around with beyond what the standard bmw service says, based on the invoices I have.
 

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Hi

I've recently purchased a 335d e91 that's about 10 years old with 130k. Before buying I'd read it's possible to get up to 40mpg. I'm doing a lot of motorway miles with some in town driving at the end. I'm getting about 32mpg currently without booting it.

There's a bit of a hot oily smell when having a short cane but not when driving normally. The engine and gearbox have been serviced frequently and everything else done.

Can't anyone give any pointers as to the low mpg or this to be expected for this engine.

Cheers
I believe the UK version originally had fuel economy spec was 37.7mpg. So 32mpg doesn't seem out of the ordinary. If you are smelling oil, that could be something to check, and the source may be something contributing to fuel economy. How are your tires?
 

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Try putting 93 octane gas:rofl:
In a diesel?
No thanks.

Recommend sticking with top tier diesel, as in shell or Exxon whenever possible. 40mpg is fake. 32 sounds about right. My throttle position sensor is starting to throw a code. Any check engine lights? Also may be about time for de carbon cleaning if another service is due I.e. Turbo work. Mine was fine during high pressure fuel pump service.

Sent from my iPhone using Bimmerfest mobile app
 
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