Oily inlet manifold and pipes.

[Dieselman]

Bolide

Where is the Lamda sensor located on the 300?
My 98 606 Turbodiesel doesnt have a Lamda sensor neither has the wifes 603.
Very interested to know where its located, before or after the CAT etc?

Thanks,

230K

Nada, Nil, Nein....Lambda sensor.

 

[Dieselman]

Nick the lambada is there to check the exhaust emmisions it feeds back to the ECU that adjust the mixture accordingly Some cars have up to 3.

malcolm

Not on a diesel.
There is no mixture control as there are no throttle flaps. The engine draws the maximum volume of air for every cylinder charge irrespective of the power being produced. (Ok turbo charging will alter this a bit but that's not the issue here.)
The diesel engine output (let's call it power although that would be wrong as an engine only produces torque not power) is governed by the amount of fuel injected into the cylinder. The mixture can be anywhere between about 25:1-30:1 and 14:1 (stoichiometric) depending on the torque output required.

This is why EGR was introduced for diesel engines at low load because all the free oxygen was creating Nox under lean conditions. The EGR gas is simply inert gas to reduce the volume of oxygen.

Everyone I have known that is into petrol engines and tuning finds it difficult to understand the concept of how a diesel engine works due to the lack of regulated mixture.
A petrol engine only has throttle flaps for exactly the reason that it has to control the mixture within tight boundries, a diesel does not.

Please nobody take this post as preaching, just a bit of information.

Regards

 

[230K]

Hi

Thanks Dieselman beginning to think I was stupid, thanks again for putting the story right.

230K

 

[bolide]

Good explanation!

The other byproduct of all this is zero inlet manifold vacuum. So the diesels run an air pump to create vacuum for the brake servo. I assume it's also used for the pneumatics for the EGR & inlet manifold resonance butterflies and for controlling the auto box

Lamson Tube-era technology - I love it!

Nick Froome
www.w124.co.uk

 

[Parrot of Doom]

http://www.mercedesshop.com/shopforum/showthread.php?t=168261

 

[Parrot of Doom]

Its on the exhaust manifold with 2-3 wires on it.

Malcolm

Malcolm is it device 140 on this page:

http://www.detali.ru/cat/oem_mb2.as...22.608&CT=M&cat=19T&SID=14&SGR=045&SGN=03#007

Or is it 137 - I'm assuming that 137 and 140 are interchangeable depending on the engine configuration.

Or should I be looking down near the Turbo instead?

 

[Dieselman]

I assume youre question is "is this the EGR valve?" If so then yes it is.

The link was an interesting way to stop the EGR working although instead of using the vacuum switch just use a relay powered from the EGR valve power leads.

 

[Parrot of Doom]

I found a helpful link. I'm still not quite clear on how the manifold unscrews from underneath, but a dry day should help that.

http://www.mercedesshop.com/Wikka/OM606962GlowPlug

/edit

I read it again, 14 bolts on the topside, and 2 bolts below - one on each side of the clamp. One accessible from above, one from below.

Doesn't sound like a big deal, I'll just have to wait for it to stop raining.

Whats a good chemical I could use for cleaning all that gunge out? I know its gunged up to heck because the mechanic showed me when I had the glow plugs done.

 

[Dieselman]

It'll take about 20 tops minutes to get the manifold off.

Car on ramps, remove centre undertray,
from below undo vertical allen bolt from induction pipe to EGR valve body.
from above undo 14 torx bolts that hold manifold to head then the EGR pipe to valve clamp.
Pull EGR vacuum hose off transducer and feed through, remove MAP sensor from inner wing and disconnect electrical connector.

lift manifold starting at the head then lift EGR valve away from feed pipe and induction pipe.

Any solvent cleaner will work or even diesel.

 

[Parrot of Doom]

Right, thanks Malcolm. When I do it I'll post a HOWTO.