W211 E320 CDI Auto g/box question.

[Peter DLM]

Now, this may just be because I've never driven an Auto Diesel before, but I have noticed something on my mate's car that I'd like an experienced member to confirm for me.

When pulling away from standstill, depending on throttle position, the revs climb to 2k, or 2.5k, and appears to be slipping before the roadspeed matches the revs and it locks up and then acts 'normally' beyond this rev range and through the gears.

On my petrol E320 the revs don't climb anywhere near 2k and the torque convertor appears to lock up a lot earlier than the diesel equiv.

Is the described behaviour a feature of the diesel engine/gearbox characteristics, and quite different to the petrol engine, or is there possibly a problem with it?

 

[uhayat]

Interestingly my W211 E220 CDI feels exactly the same way. Lets see if anyone has an explanation to it.
Usman

 

[lynall]

I actually thought it would be other way around, what with turbo diesels having more torque than the petrols.



Lynall

 

[BlackC55]

is that in comfort mode or winter?

 

[Peter DLM]

Erm..... good question.... I don't know. I'll give him a ring and double check.

Lynall, all the modern diesel engines I've experienced so far have been totally gutless until on boost (talking about 4cyl stuff here) the 'old' diesel characteristics do not appear to feature in the modern ones.

 

[w124coupe]

Been the same for all diesel 7G utos that I've been in - maybe the software tries to keep the engine on boost to improve smoothness?

If you ignore the revcounter it does seem to work!

 

[Druk]

Mine does the same. Try flooring it with a weight on the back (heavy caravan) and see what happens. Sometimes gets over 3000rpm before settling down. I've had it test driven by dealer techie foreman who proclaimed it 'normal'.

Mind you...with a running weight approaching 4tons the ability to outdrag quite a few things from a standing start is impressive.

 

[Gareth]

mine is exactly the same.

 

[Peter DLM]

is that in comfort mode or winter?

The choices are Comfort or Sport, and this was in Comfort mode.

Apparently this is normal behaviour. Thanks everyone for your responses.

The diesel engine is obviously more vocal than the petrol at standstill and pulling away, this feature allowing the revs to climb to >2k as one pulls away seems to make it a little more painful. It's just something I'm going to have to get used to I think.