Oily inlet manifold and pipes.

[Dieselman]

Particularly as it's aluminium...

Nick Froome
www.w124.co.uk

Nick
The exhaust manifold carries the stainless pipe and is definately made of cast iron. There have been odd members with cracked exhaust manifolds.

 

[GazCaff]

Sorry, cant agree here.

EGR is caused when the volume of oxygen goes high compared to that of the fuel. This can only happen at low load conditions and especially at idle. The EGR valve is only actuated under these conditions.

Maybe you are thinking of petrol engines, don't forget there is no such thing a WOT on a diesel as the volume of air is constant per revolution as there is no throttle?

Surely a turbocharger would cause variation to the volume of air?

 

[bolide]

Nick
The exhaust manifold carries the stainless pipe and is definately made of cast iron. There have been odd members with cracked exhaust manifolds.

Just realised you were talking about the exhaust manifold... I have the (aluminium) inlet manifold etched on my mind as I've taken one off recently!

Nick Froome
www.w124.co.uk

 

[television]

EGR valves are there to return harmfull gasses back into the engine at cruise and idle. When they fail, it is a waste of time cleaning as the spring is probably weak, they normally jam up,partly open.

Malcolm

 

[bolide]

Nick
The exhaust manifold carries the stainless pipe and is definately made of cast iron. There have been odd members with cracked exhaust manifolds.

Sorry - I wasn't paying attention. I was referring to the inlet manifold. D'oh!

Nick Froome
www.w124.co.uk

 

[television]

Parrot, have you tried changing the EGR valve, its a waste of time cleaning them,when they go they normally stick parcially open.

malcolm

 

[KLP 92]

Parrot, have you tried changing the EGR valve, its a waste of time cleaning them,when they go they normally stick parcially open.

malcolm

Easier to disengage them all together! Just disconnect the vaccum pipe.

 

[television]

Easier to disengage them all together! Just disconnect the vaccum pipe.

Not when they are stuck half open, that being the biggest fault or reason for failure.

Malcolm

Check this out, at the bottom

 

[Parrot of Doom]

Hmmm, I might consider that. Whereabouts would it be on my engine?

 

[television]

Hmmm, I might consider that. Whereabouts would it be on my engine?

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

Malcolm

 

[bolide]

While we're on the topic, why is there a Lambda sensor in an E300 Diesel with no turbo?

I've read that the car has electronically-stabilised idle and suspect it's used for that. But how does idle stabilisation work on a diesel?

My old 250TD sat at 700 rpm perfectly with no electronics...

Nick Froome
www.w124.co.uk

 

[Parrot of Doom]

Your old 250TD probably didn't have a cat though.

 

[television]

While we're on the topic, why is there a Lambda sensor in an E300 Diesel with no turbo?

I've read that the car has electronically-stabilised idle and suspect it's used for that. But how does idle stabilisation work on a diesel?

My old 250TD sat at 700 rpm perfectly with no electronics...

Nick Froome
www.w124.co.uk

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

 

[bolide]

Your old 250TD probably didn't have a cat though.

True. But why have a Cat and a Lambda sensor and no ECU or fuelling control?

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.

But there's no ECU, no turbo, no means of controlling fuel or air feed...

So the Cat catalyses the exhaust, the Lambda sensor checks CO and then what? The car has a mechanical injection pump and no throttle. It does, however, have the EGR and inlet manifold butterfly valves - and they're pneumatically-controlled

Beats me why it's there. Maybe it's for the turbo cars and they didn't bother removing it. But AFAIK there's no ECU or fuelling control in the turbos either!

Nick Froome
www.w124.co.uk

 

[230K]

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

 

[television]

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

It has to be before the CAT so that it can protect it, that's why they always recommend that you change it when you have new CATs if you put up the first 6 number of the VIN you can have more details.

Malcolm

 

[television]

True. But why have a Cat and a Lambda sensor and no ECU or fuelling control?


But there's no ECU, no turbo, no means of controlling fuel or air feed...

So the Cat catalyses the exhaust, the Lambda sensor checks CO and then what? The car has a mechanical injection pump and no throttle. It does, however, have the EGR and inlet manifold butterfly valves - and they're pneumatically-controlled

Beats me why it's there. Maybe it's for the turbo cars and they didn't bother removing it. But AFAIK there's no ECU or fuelling control in the turbos either!

Nick Froome
www.w124.co.uk

Nick if you let me have the first 6 numbers of the VIN I will check it out correctly.

malcolm

 

[bolide]

A W124 300 Multivalve Diesel VIN starts WDB1241912F. In the final 6 digits they start at around 280xxx and go up to about 330xxx in the ones I've seen

Nick Froome
www.w124.co.uk

 

[230K]

It has to be before the CAT so that it can protect it, that's why they always recommend that you change it when you have new CATs if you put up the first 6 number of the VIN you can have more details.

Malcolm

Hi

Some cars have the Lambda sensor after the CAT, particularly petrol ones, this i believe is how the "Closed Loop" works testing the emissions after after the CAT and altering fueling to suit????? Have i got that right.

Come to think of it a petrol Beetle i had on the ramp just last week had the Lambda sensor after the CAT.

230K

 

[Dieselman]

While we're on the topic, why is there a Lambda sensor in an E300 Diesel with no turbo?

I've read that the car has electronically-stabilised idle and suspect it's used for that. But how does idle stabilisation work on a diesel?

My old 250TD sat at 700 rpm perfectly with no electronics...

Nick Froome
www.w124.co.uk

No Lambda sensor as the Cat isn't a 3-Way closed loop, it's a 2-way oxydisation jobbie with no regulation of exhaust gas as it isn't required. Due to not having mixture control diesel cat's don't need or have use for lambda sensors.
There is no need for the Cat to bother trying to convert Co on a diesel as there isn't enough of it to bother about, unlike a petrol engine. A diesel engine outputs less Co than a catalylsed petrol.

The idle stabilisation on your car works by the ECU monitoring the engine revs and applying a voltage to a solenoid motor on the back of the fuel pump rack. Later cars with full electronic control pumps just take this a step further and use it for the full rev range (drive by wire).