W211 E320cdi 7G poor consumption

[gIzzE]

However........my car doesn't kick out under smoke under acceleration when using 2 stroke, I have not put any in for the last tank and a half and already it is giving a little puff of smoke again, easily seen with headlights behind.

 

[Bellow]

However........my car doesn't kick out under smoke under acceleration when using 2 stroke, I have not put any in for the last tank and a half and already it is giving a little puff of smoke again, easily seen with headlights behind.

The smoke you are witnessing can only be from overfuelling or mistimed fuelling.
Whatever aspect of the 2 stroke oil stops that, it isn't detergency. More likely it is either its Cetane number different from the Diesel fuel affecting combustion, or, its increased lubricity allowing smoother, more controlled injector operation. It could also be lubricating the solenoid valve that regulates rail pressure.
I'd bet that it's the additional lubricity of the solenoid actuated mechanical components, a sharp injector cut-off being essential for a smoke-free exhaust.

 

[jon_viola]

The one question you haven't answered is what temperature is it getting to? It should be at 92ºc and get there within around 10 minutes, at 80ºc it is over fuelling by around 15%, at 70ºc it is over over fuelling by some 25%.

Just looking on Eurocarparts and they list a 92 and an 87 deg thermostat for my car. Guess I'm looking for the 92 from what your saying.

 

[gIzzE]

Yeah, go with the 92°c one.

What make actually, make sure it is Pierburg or Bosch.

 

[V12]

I'm pretty sure last time I checked it was the same price from MB dealer anyway.

 

[Bellow]

A couple more factors that may contribute to 2 stroke oil slightly altering combustion characteristics. The flash point for Diesel is 100-130F, greater than 400F for 2 stroke oil.
The viscosities are markedly different. At 40C for both, Diesel's is 2-6cSt, 2 stroke oil's 142.7cSt.
Admittedly the quantity of 2-stroke oil is very low but the physical characteristics will affect things like surface tension which in turn influences droplet formation and atomisation.
For direct petrol injection at 100-200 bar droplet size is down to 15 microns (15thousandths of a millimetre!) Diesels operating with 1500-2000bar?!! The point though is that it is a very finely judged process which is easily affected by the characteristics of the injected liquid.

 

[jon_viola]

It's not a Bosch or Pierburg but at £26 delivered has to be done!

Is there a instruction page somewhere?

 

[gIzzE]

No it doesn't, often many are crap out of the box.

Only go with Bosch or Pierburgh.

Never buy an aftermarket MAF.

 

[jon_viola]

Yep your right on the MAF but have used these thermostats before on my 2 I6 versions of the E320cdi with no issues and many many miles.

Wonder if currently mines the 87deg version? Would tally with the display and might help things all round.

 

[BlackC55]

Maybe it's had a bad remap?

 

[V12]

Maybe it's had a bad remap?

This...

 

[jon_viola]

Maybe. Lets hope a good ragging and a new thermostat help things....

 

[jon_viola]

Just a thought but do the V6 CDI's have a record of boost leaks? My V6 makes a sssshhhhhhh sound but my old I6 sounded more like a traditional turbo whistle.....

 

[jon_viola]

Just a thought but do the V6 CDI's have a record of boost leaks? My V6 makes a sssshhhhhhh sound but my old I6 sounded more like a traditional turbo whistle.....

Update time. This turned out to be a loose exhaust. All now sorted and boosts very well!

 

[Herishi]

Here is the pic...

That was sat at between 45 and 60mph most of the way, so not really pushing on, but still the best I had ever seen by quite some margin.

Wow that's a dream for me. I do a 16 mile run 90% at 56-60mph and get 36mpg :-(

 

[Brooks22]

Best I've ever managed in my E320 was 40.6mpg. That was on an 80 mile round trip using a lot of cruise control. Normally i see between 32 and 36 in mixed driving. Around town only is usually about 28 or 29.

Seems like there's a lot of variation between cars too.

 

[merc85]

Mpg i6

Got this on a steady drive back from Colchester after getting a new ignition key.

s211 e320 cdi (53)

View attachment 51891

 

[V12]

Cruise at 40mph?!

 

[merc85]

Cruise at 40mph?!

no bud 56mph

 

[Graham 71]