Noddy 99

[Noddy 99]

Hi, chaps,

Since about last summer (so nothing to do with cold weather factors), I've been getting really poor mpg figures - even on the longest, gentlest runs, I haven't been able to to get above 35mpg.

The figures have been so uniformly low that I'd suspected a fuel leak. The engine bay is completely dry with no smell of diesel anywhere in the car so I've sort of ruled that out.

Anyway, for the first time in ages, I ran an iCarSoft scan and it threw up this instantly (see picture)

So I'm a bit confused about my next step - what part would I need to get and is this an easy DIY installation? I've done glow plugs, PCV valves and swirl flap actuators so I'm not a total novice... Can you guys help?

There is a further complication: I'm having my performance map removed to return the car to stock (long story but I'm going ahead) - do I replace this sensor BEFORE the map removal or AFTER?

Trusting in some seriously wise guidance from you guys - you always know far more than I do...

W211 2009
E280 CDI Sport
VIN: WDB2112202B397779

 

[Wighty]

It might be the MAF , it’s a part inside the batwing ?? I would wait for someone to confirm that though .

 

[Botus]

26 round town 42 on a run... can't seem to get past that - once got 44 but never repeated on the same trip many times since

yep two sensors in the bat wing one each side - not sure if they come separately - or you are meant to buy the whole thing

top tip refitting the bat wing - loosen the air cleaner box bolts each side so it lines up better - do up the jubilee clips, then bolt the air boxes tight and don't stress too much on the turbo one - its sucked on, not boosted off - should have RED silicon thingy there and on the engine breather pipe - if the breather has black soft silicon each end.... its an obsolte part that has probably failed inside

 

[Botus]

make sure they are plugged in OK - and you could try cleaning with electrical glue sniffer stuff - throws a light if the wire isn't clipped home correctly...

 

[Wighty]

As above , I would try cleaning the batwing by spraying the inside with carb cleaner . I clean mine when I change the air filters or remove the batwing for any other reason .
If my car was doing 20 miles on the motorway on cruise in roadworks at 50mph and I reset the trip/mpg it would be right up near 50mpg

 

[alexanderfoti]

This fault code is usually an indication of a boost leak. Freeze frame data from the fault code will point you in the right direction.

 

[Noddy 99]

This fault code is usually an indication of a boost leak. Freeze frame data from the fault code will point you in the right direction.

Ah, how do I get that freeze frame data? I might have overstated my credentials...

 

[Botus]

"live data" I imagine... aka what its telling you when running in other menu chocies on your gadget.....

 

[Noddy 99]

"live data" I imagine... aka what its telling you when running in other menu chocies on your gadget.....

Ah, I think I get it. I've never actually studied the fault code data before so I'll have a look at that...

On the wider issue, I think I'll wait until the performance map is removed before I draw any conclusions about replacing parts. Could the remap have actually CAUSED this?

Mileage is now about 108,000
Would have been about 103,000 at the remap

Car is running fine - it's only the poor economy and the fault code which would point to there being anything wrong...

 

[Botus]

On the wider issue, I think I'll wait until the performance map is removed before I draw any conclusions about replacing parts. Could the remap have actually CAUSED this?

Car is running fine - it's only the poor economy and the fault code which would point to there being anything wrong...

no

the map might be causing it to use more

if the EGR and turbo are clogged up it won't run as it should....

 

[Noddy 99]

EGR was thoroughly de-coked about 6000 miles ago. I did a lot of work on the car around January last year - air filters, EGR, fuel filter, PCV valve, swirl flap mod... can't remember everything...

That was all BEFORE the remap - haven't really touched it since then...

 

[Botus]

wighty's idea you can see 50mpg sounded extraordinary... where's the stupid 3 second clear it button ? .... pressed everything on the wheel loads of times and it didn't clear anything - does this car have the most mind boggling wheel button / mad menu set up you could ever miss-create ?

how did u get the EGR off ? on my father's that thing is stuck fast -

 

[Wighty]

wighty's idea you can see 50mpg sounded extraordinary... where's the stupid 3 second clear it button ? .... pressed everything on the wheel loads of times and it didn't clear anything - does this car have the most mind boggling wheel button / mad menu set up you could ever miss-create ?

how did u get the EGR off ? on my father's that thing is stuck fast -

On mine it’s press the reset /dash light nob on the bottom left of the instrument cluster , Noddy will know he has the same car .
It’s just the way I check the car is running correctly every so often on long roadwork sections .

 

[supernoodle]

Freeze frame / snapshot data is a record of parameters at the time the fault set.

Now the nerdy bit, technically Freeze Frame is the data get when you access the module using the generic OBDii/EOBD mode on the diag tool. If using manufacturer specific diag mode on tool it's a Snapshot Record.

The difference is manufacturers have to provide some freeze frame data to comply with OBD regs, but usually just the bare minimum. The snapshot is for their technicians, so should be more comprehensive and tailored for the fault. Note in both cases contents are set by MB.

Certainly on my iCarsoft I can only access freeze frame data, so have to go in using OBD mode. Another shortcoming of the iCarsoft.

 

[alexanderfoti]

Mb refer to it as Event Data.
Event data can be stored without the presence of a DTC

 

[alexanderfoti]

Coluld the remap have actually CAUSED this?

Its unlikely, but it will make a small boost leak more obvious to the computer, so the fault code may "disappear" on the stock map, but still be leaking.

 

[Noddy 99]

wighty's idea you can see 50mpg sounded extraordinary... where's the stupid 3 second clear it button ? .... pressed everything on the wheel loads of times and it didn't clear anything - does this car have the most mind boggling wheel button / mad menu set up you could ever miss-create ?

how did u get the EGR off ? on my father's that thing is stuck fast -

Yes, the wheel button menu is absolutely unfathomable! But that's not where the reset switch is - as Wrighty says, it's a single protruding plastic knob at the bottom left of the instrument cluster.

Regarding the EGR, it came down to brute force if I remember. I almost gave up then tried one colossal clout and saw a sliver of movement...

 

[Noddy 99]

Its unlikely, but it will make a small boost leak more obvious to the computer, so the fault code may "disappear" on the stock map, but still be leaking.

So if there IS a leak, what is it that is actually leaking (ie what component) and how do I fix it?

Appreciate your help.

 

[alexanderfoti]

So if there IS a leak, what is it that is actually leaking (ie what component) and how do I fix it?

Appreciate your help.

That I can to tell you! Boost hoses splitting are common, but essentially any join or hose could leak. Outlet of turbo o ring etc.

 

[Wighty]

If the fault is MAF related for one side of the MAF (current fault is Left only)and you unplug both side from the sensors , will the fault show the same codes for both Left and Right MAF ?