Issue with 2011 Mondeo 2.0 Diesel

diesel_doglet

Hi All,

I hope someone on here may be able to help me on this one. I have an intermittent issue on my Mondeo 2.0 Diesel. (2012).

Intermittently when driving the car will feel sluggish and the revs will feel irregular. When this occurs and the car is not moving the fuel usage runs at 0.5Gal / hr. Usually when stationary with engine running the car shows usage of 0.1Gal / hour so something is causing the car to drink fuel at a rate of five times the usual. Also when this occurs the car smells warm/hot a bit like burning rubber.

This has been doing this on and off for a few months now but is getting more regular. Usually if I am driving a distance this passes or usually stops after the car has been stopped and idle for 10 minutes or so.

No warning lamps come up on the dash so I am at a loss. If anyone has any ideas where I can start I would be most grateful.

Thanks
DD

AdrianC

diesel_doglet wrote: »

I hope someone on here may be able to help me on this one. I have an intermittent issue on my Mondeo 2.0 Diesel. (2012).

Intermittently when driving the car will feel sluggish and the revs will feel irregular. When this occurs and the car is not moving the fuel usage runs at 0.5Gal / hr. Usually when stationary with engine running the car shows usage of 0.1Gal / hour so something is causing the car to drink fuel at a rate of five times the usual. Also when this occurs the car smells warm/hot a bit like burning rubber.

Sounds like DPF regeneration. Extra fuel is used because it's being injected into the filter to burn off the collected soot. It's perfectly normal.

If it's doing it more often, then it may be that the filter is starting to get a bit clogged, and the automatic regeneration isn't clearing it fully. It may be resolved by a forced regeneration in a garage, or it may need the filter removing and cleaning or replacing.

diesel_doglet

AdrianC wrote: »

Sounds like DPF regeneration. Extra fuel is used because it's being injected into the filter to burn off the collected soot. It's perfectly normal.

If it's doing it more often, then it may be that the filter is starting to get a bit clogged, and the automatic regeneration isn't clearing it fully. It may be resolved by a forced regeneration in a garage, or it may need the filter removing and cleaning or replacing.

Many thanks for this - I wll hop down to the local halfords and get some DPF cleaner. Hopefully that will sort it - I will report back.

many thanks

AdrianC

Homeopathic fuelgoop is about the one thing I wouldn't bother with.

Exemplar

Terraclean

AdrianC

Ah, yes. My apologies - there's another overpriced scam I wouldn't bother with.

diesel_doglet

AdrianC wrote: »

Homeopathic fuelgoop is about the one thing I wouldn't bother with.

I will give it a try as its a relatively cheap fix if it works. If not, may I ask what you would suggest?

thanks

Goudy

This does sound like a DPF problem AdrianC suggests.

These filters trap soot and every so often will post inject fuel to cause a burn to turn the soot into smaller ash particles.

You don't mention what the mileage is, but it could be the filter is full of ash now and at the end of it's life rather than a problem with the regen cycle, but you do need someone to check it out, like a diesel specialist.

You also need to check the engine oil asap as well.
Repeated attempts of DPF regeneration like this will almost certainly allow excess fuel to pass the piston rings on the post injection cycle and overly contaminate the oil causing the oil level to rise.

Too much oil/fuel in the sump can find it's way out via the engine breather (which is plumbed into the air intake hose) and the engine will run away on it until it goes bang, so have a quick look now before it's too late!

forgotmyname

Injecting diesel that burns inside the exhaust to help emissions... Wonder what the emissions are when its doing that regen???

To get the emissions down the fuel economy drops 6mpg over a long mostly motorway and dual carriageway journey compared to a car without the DPF.

Puzzled how that works.

Goudy

There are different harmful emissions on all engines, not just diesels.
Though diesels do produce more of some than others.

They produce lower CO2 than petrol engines, but higher levels of particulates (soot).
The DPF and the extra injected fuel helps control these particulates.

Interestingly another harmful diesel emission is actually caused by it the modern diesel engine being so efficient.
Modern common rail diesels will inject no fuel on the over run unlike older pump timed diesels.
This causes the engine to run very very lean. This lean combustion is very very hot and creates lots of harmful nitrogen oxides.
To control these NOx's, modern diesel vehicles require Exhaust Gas Recirculation valves (EGR) and Selective Catalytic Reduction systems (SCR) which pump Adblue into the exhaust to reduce the NOx's.

When all is working well under the right conditions there's little trade off, the extra fuel and adblue use is negligible.
Mile munching a diesel down a motorway at steady speeds will cause only a moderate amount of soot for the DPF to deal with requiring less frequent regens with little post injected fuel and only small amounts of NOx are produced due to combustion temps being fairly stable.

Unfortunately, it wasn't long ago Joe Public was tempted into diesels on CO2 emission and fuel economy and a lot of diesel vehicles are never used under the right conditions.

Short trips with cold engines and on and off the throttle city driving causes havoc with the emissions of soot (cold engines run rich and produce more soot) and NOx's and the equipment to control them just can't cope, they are not just overloaded so use more fuel to regenerate (and Adblue to control the NOx's) but often fail to complete their cycle due to the engine being shut down before they finish.

wongataa

Goudy wrote: »

To control these NOx's, modern diesel vehicles require Exhaust Gas Recirculation valves (EGR) and Selective Catalytic Reduction systems (SCR) which pump Adblue into the exhaust to reduce the NOx's.

Not all diesels require additives like Adblue for NOx control.