Mystery freelander TD4 idle issue

Nodge68 said:

Sorry Joe. I couldn't resist seeing if that tractor loving dope would show up. It's so funny to taunt someone well and truly stuck in the early days of diesel power.
I'm waiting to read the answer as to what the TD4 MAF is actually for.

Click to expand...

Sadly for you and your mate Joe you don't have a bloody clue what you are on about. What the MAF is for has already been explained and Joe's description of how a petrol fuel system is arranged in the case of a diesel is a little laughable. You are both totally clueless.

Joe_H said:

Errrm, Mr Moron... Nobody here is talking about EGR.. WTF ate you talking about ? - or - do you want to start another 'think before you post'' thread' You have obviously not moved on from tractors of the 1950's to any modern diesel. Diesels are 'controlled' (throttled if you want' by 'air' (loose term for morons like you) in relation to O2 content and a precise fuel mix. You REALLY have not got a clue. I am amazed. You can read fact, or you can believe fiction. You are thee Beatrix Potter of Diesel engine operations. Absolutely unbelievable.
Good to have 'enticed you back' though, the dumb factor from you is a pleasure to behold and written forever on these walls - I will quote every post so you cannot change your tiny mind.

Ok, numbskull -- - WHAT is a MAF sensor on a TD4 ? - what function does it perform oh knowledgeable one. ? - I await your description with lube in hand...

"Wammers, the things you know wouldn't fit on a postage stamp."

Click to expand...

Read my answer again and see if the penny drops. All diesels are throttled by fuel, i will say again, at any given manifold pressure air is constant only the fuel quantity is change to accelerate or decelerate the engine.

Sure a diesel makes more power, the more fuel is added. However the MAF is there to make sure there is always an excess of air available to burn the fuel. Diesels are nolonger permitted to just throw uncontrolled amounts of fuel into the cylinders. That's why the ECU needs know how much air is entering the engine. If the MAF signal is reduced for whatever reason, then the ECU will always reduce the fuel to maintain a clean burning mixture. That's why a modern diesel has a MAF sensor. It's secondary function is to measure the air mass reduction during the EGR cycle.

Nodge68 said:

Sure a diesel makes more power, the more fuel is added. However the MAF is there to make sure there is always an excess of air available to burn the fuel. Diesels are nolonger permitted to just throw uncontrolled amounts of fuel into the cylinders. That's why the ECU needs know how much air is entering the engine. If the MAF signal is reduced for whatever reason, then the ECU will always reduce the fuel to maintain a clean burning mixture. That's why a modern diesel has a MAF sensor. It's secondary function is to measure the air mass reduction during the EGR cycle.

Click to expand...

Total and utter nonsense. You do not have a clue what you are talking about. If the engine was rotating at light throttle demand say 1500 RPM low load. The EGR maybe active, this may lead to up to a 50% reduction in air flowing through the MAF yet fuel is not reduced, if it was the engine would slow down. So don't talk rubbish. The remainder of the charge is made up from inert exhaust gas to reduce combustion temperature and reduce Nox production. But there is still enough oxygenated air to service the power/throttle demand and to burn the fuel needed to be injected to give that throttle power demand. EGR does not work on idle nor on acceleration or with high power demands. Idle is controlled by the ECU idle which is switched on at below 7% throttle pot. In the last two instances fuelling is controlled by the ECU in response to throttle/power demands subject to readings from the MAP sensor nothing to do with MAF. You really don't have a clue.

wammers said:

Total and utter nonsense. You do not have a clue what you are talking about. If the engine was rotating at light throttle demand say 1500 RPM low load. The EGR maybe active, this may lead to up to a 50% reduction in air flowing through the MAF yet fuel is not reduced, if it was the engine would slow down. So don't talk rubbish. The remainder of the charge is made up from inert exhaust gas to reduce combustion temperature and reduce Nox production. But there is still enough oxygenated air to service the power/throttle demand and to burn the fuel needed to be injected to give that throttle power demand. EGR does not work on idle nor on acceleration or with high power demands. Idle is controlled by the ECU idle which is switched on at below 7% throttle pot. In the last two instances fuelling is controlled by the ECU in response to throttle/power demands subject to readings from the MAP sensor nothing to do with MAF. You really don't have a clue.

Click to expand...

No one mentioned the MAP sensor. We're talking about the MAF sensor and what it is for.
You obviously haven't been keeping up with modern common rail diesels. The MAF is there to measure air mass. The ECU needs this to ensure that the fuel to O2 ratio is never exceeded. This ensures black smoke production is kept to a minimum.
Don't believe me. Research it yourself.
Every common rail diesel today uses the same black smoke limitation strategy.

Why do you think an old, tired, low signal MAF reduces engine performance? I'll tell you why. Because the ECU strategy is to ensure that fuel never exceeds the available O2 to burn in. With a low MAF signal, the ECU thinks less O2 is in the cylinders, so it limits fuel volume to a lower limit, ensuring minimal black smoke. The byproduct of reduced fuel volume, is a lower then expected power output.

There's nothing new about this way of fueling diesel engines.
Just like there's nothing new with auto brake adjusters, VCU's, electricity or anything else you clearly don't understand.

Now then Tractor man It is unfortunate that as engine management systems became more intelligent - err - you did not !. You really really do not understand your subject at all. It would seem you are simply too old and pig headed to actually learn anything.

wammers said:

Diesels are throttled by fuel NOT bloody air, what part of that do you not understand? Dear me. At idle of 780 RPM with there is 487.75 cc of air in the firing cylinder. The ECU is injecting enough fuel to maintain 780 RPM into that air. The mixture ratio at this time will be well over 100 to 1 how is the airflow through the MAF effecting that. If there was no turbo to consider for easy of explanation, with the engine flat out there would still be 487.75 cc of air in the firing cylinder. The only thing that changes to make the engine rev flat out is the fuel being injected into that air. If there was no EGR on the engine to accommodate ECD 2 and up there would be no need for a MAF sensor.

Click to expand...

Typical tractor consideration that is wrong - firstly you totally and incorrectly presume that your quantity of 'air' in the cylinder will be the same at idle as it would when 'flat out' (on a non supercharged unit). It is absolutely not. Volumetric efficiency is non linear. (ie, the quantity of 'air' in the cylinder will vary at differing speeds and loads).FACT
That was the basic premise of mechanically controlled diesels. - very crude. and very inefficient'
MAF, for example - on an L series - is there to monitor egr operation and report any issues (that is it's only function). The ECU controls the egr hence knows exactly when and how much it is open, MAF informs the ecu of the flow reduction and the ecu confirms what it expects to see a drop in air flow. '
The L series is far more 'intelligent' than you or your tractor though. It relies heavily on information from multiple maps (around 24 in the L series ECU). Its main feedback circuits for fuel control are TPS and MAP. Map alone is not sensitive enough to monitor the egr operation on a diesel.
Better than the tractor and more intelligent than you, however, still relatively poor in terms of efficiency and emissions- BUT we are not discussing an L series here old man. -

wammers said:

Total and utter nonsense. You do not have a clue what you are talking about. If the engine was rotating at light throttle demand say 1500 RPM low load. The EGR maybe active, this may lead to up to a 50% reduction in air flowing through the MAF yet fuel is not reduced, if it was the engine would slow down. So don't talk rubbish. The remainder of the charge is made up from inert exhaust gas to reduce combustion temperature and reduce Nox production. But there is still enough oxygenated air to service the power/throttle demand and to burn the fuel needed to be injected to give that throttle power demand. EGR does not work on idle nor on acceleration or with high power demands. Idle is controlled by the ECU idle which is switched on at below 7% throttle pot. In the last two instances fuelling is controlled by the ECU in response to throttle/power demands subject to readings from the MAP sensor nothing to do with MAF. You really don't have a clue.

Click to expand...

As my paragraph above - the ECU is fully aware of egr opening as IT controls it. The reduction in 'air' via the egr operation is monitored by the maf. The ECU knows what it needs to do. There will be no 'engine slowing down due to MAF flow reducing' - doh... I have told you this before old man, yet you do no listen or cannot understand.

Now we will move on to the TD4, this is way beyond your comprehension apparently.
On any diesel the MAP sensor alone is not able to measure MASS FLOW. - it can only measure absolute pressure. The ecu can make an educated guess as to the fuel quantity to inject via such things as rpm and tps, fuel pressure and injector pulse width.. but as said - the volumetric efficiency is not linear.(FACT) - To maintain a more accurate system of engine control the TD4 uses the MAF as a main system indicator. In this ECU the MAF is critical to efficient operation throughout the operating envelope. Extremely accurate MASS AIR FLOW data is fed back to the ecu and combined with all other sensor information and known internal ecu information the engine is operated in a MAF closed loop. It will not operate correctly without the MAF (If the MAF is completely failed there is a fall back basic map in the ecu that it refers to, performance is reduced and fuel consumption and emissions increase - and this is NOTHING to do with EGR). The MAF (AIR MASS ENTERING THE ENGINE) is a critical and main component of engine fuelling control on that engine. FACT.

Now, please, fer fecks sake go away and play with your mechanical governers...
Also, 'think before you post' - dont just google 'modern tractors'

"yes, you are quite WRONG again dear Wammers."

"Wammers, the things you know will not even fit on a stamp."

Nodge68 said:

No one mentioned the MAP sensor. We're talking about the MAF sensor and what it is for.
You obviously haven't been keeping up with modern common rail diesels. The MAF is there to measure air mass. The ECU needs this to ensure that the fuel to O2 ratio is never exceeded. This ensures black smoke production is kept to a minimum.
Don't believe me. Research it yourself.
Every common rail diesel today uses the same black smoke limitation strategy.

Why do you think an old, tired, low signal MAF reduces engine performance? I'll tell you why. Because the ECU strategy is to ensure that fuel never exceeds the available O2 to burn in. With a low MAF signal, the ECU thinks less O2 is in the cylinders, so it limits fuel volume to a lower limit, ensuring minimal black smoke. The byproduct of reduced fuel volume, is a lower then expected power output.

There's nothing new about this way of fueling diesel engines.
Just like there's nothing new with auto brake adjusters, VCU's, electricity or anything else you clearly don't understand.

Click to expand...

Eeee morning Nodge - we posted together... how fortunate lol


edit - and to add - to the things he does not understand - there was his tirade about some crappy battery monitor not long ago where he talked out of his bottle or bottom -? unsure which - probably both lmao !

Nodge68 said:

No one mentioned the MAP sensor. We're talking about the MAF sensor and what it is for.
You obviously haven't been keeping up with modern common rail diesels. The MAF is there to measure air mass. The ECU needs this to ensure that the fuel to O2 ratio is never exceeded. This ensures black smoke production is kept to a minimum.
Don't believe me. Research it yourself.
Every common rail diesel today uses the same black smoke limitation strategy.

Why do you think an old, tired, low signal MAF reduces engine performance? I'll tell you why. Because the ECU strategy is to ensure that fuel never exceeds the available O2 to burn in. With a low MAF signal, the ECU thinks less O2 is in the cylinders, so it limits fuel volume to a lower limit, ensuring minimal black smoke. The byproduct of reduced fuel volume, is a lower then expected power output.

There's nothing new about this way of fueling diesel engines.
Just like there's nothing new with auto brake adjusters, VCU's, electricity or anything else you clearly don't understand.

Click to expand...

Sorry but you are talking out of your arse. When you know what you are talking about we can discuss it until then there is no point. The air is NOT throttled it is free flow into the cylinders that is why EGR has to be used to reduce Nox production. There is ALWAYS more air in the cylinders than the engine needs to burn the fuel. If there were no emission regulations and therefore no EGR you would not need a MAF sensor on a diesel. The MAP sensor is fundamental to the operation of a turbo diesel engine the more combustible air in the cylinders, the more fuel can be injected and the more power is produced. The variable rate turbo enables the engine to run almost like a conventional none turbo engine on low power demand which makes it more fuel frugal. Only on higher power demand does it provide progressive higher boost. The boost pressure is measured by the MAP sensor and fuel is increased by the ECU to suit manifold pressure throttle and power demand. You are confusing diesel engines with petrol engines were air flow and fuel are matched to give a mixture ratio nominally of around 14 to 1 for good combustion at all engine speeds. Diesel engines do not work like that, air for any given manifold pressure air in the cylinders is constant, the only thing that is changed to increase or decrease engine RPMs is the amount of fuel injected into that constant air. The more fuel the higher the RPMs less fuel lower RPMs simple as that. A faulty MAF will cause the ECU to throw a sicky because the ECU is receiving signals it does not understand which maybe out of range of the mapped data. MAF sensors came in on diesels with EU level 2 emissions regulations were a feedback of the amount of exhaust gas being ingested was required to minimise soot production. With level 3 which the TD4 uses a much tighter EGR control came into being where the amount of exhaust gas ingested was more finely controlled to reduce Nox even further. So any malfunctioning MAF will cause running problems as will any other malfunctioning sensor. Level 4 emissions regulations use an even tighter control of exhaust gas ingestion very close to minimal air needed for combustion to reduce Nox even further. This can cause soot generation so a particle filter was introduced to collect the soot and burn it off at higher engine speeds. You can't throw soot out in town but it's ok to do it at high speed with elevated exhaust temps on the motorway.

Joe_H said:

Eeee morning Nodge - we posted together... how fortunate lol


edit - and to add - to the things he does not understand - there was his tirade about some crappy battery monitor not long ago where he talked out of his bottle or bottom -? unsure which - probably both lmao !

Click to expand...

Morning Joe. I didn't even touch on the whole VE subject. It's way to complex for a tiny intellect to grasp. You are of course quite correct. A cylinder will draw X amount of air at idle, but as the Rpm increases the actual volume of air in the cylinder reduces, but you, as I will know that and understand why.

Dear old Joe there will be a slight variation in air over the rev range this is true, due to the cam sweet spot and to overlap and scavenge effects. Never the less there is always more air in the cylinder than the engine needs to burn the fuel from idle to flat out. ONLY the fuel injected changes from idle to flat out so it is the volume of fuel applied to generally the same amount of air that throttles the engine. You do have a lot to learn.

Joe_H said:

Eeee morning Nodge - we posted together... how fortunate lol


edit - and to add - to the things he does not understand - there was his tirade about some crappy battery monitor not long ago where he talked out of his bottle or bottom -? unsure which - probably both lmao !

Click to expand...

I read the thread but couldn't be bothered to get involved in that one.
There's only so much you can teach an old dog.
I'm waiting for him to try proving black is white because that's the loonicy I'd expect.
He definitely has trouble reading, and understanding. My I should use a font he might recognise?
Maybe Times New Roman would get the message through?

Nodge68 said:

Morning Joe. I didn't even touch on the whole VE subject. It's way to complex for a tiny intellect to grasp. You are of course quite correct. A cylinder will draw X amount of air at idle, but as the Rpm increases the actual volume of air in the cylinder reduces, but you, as I will know that and understand why.

Click to expand...

Bull****. Think you had better read up on valve overlap and scavenging. Have you never heard the saying "Coming on the cam". You do talk some bloody tripe.

wammers said:

Sorry but you are talking out of your arse. When you know what you are talking about we can discuss it until then there is no point. The air is NOT throttled it is free flow into the cylinders that is why EGR has to be used to reduce Nox production. There is ALWAYS more air in the cylinders than the engine needs to burn the fuel. If there were no emission regulations and therefore no EGR you would not need a MAF sensor on a diesel. The MAP sensor is fundamental to the operation of a turbo diesel engine the more combustible air in the cylinders, the more fuel can be injected and the more power is produced. The variable rate turbo enables the engine to run almost like a conventional none turbo engine on low power demand which makes it more fuel frugal. Only on higher power demand does it provide progressive higher boost. The boost pressure is measured by the MAP sensor and fuel is increased by the ECU to suit manifold pressure throttle and power demand. You are confusing diesel engines with petrol engines were air flow and fuel are matched to give a mixture ratio nominally of around 14 to 1 for good combustion at all engine speeds. Diesel engines do not work like that, air for any given manifold pressure air in the cylinders is constant, the only thing that is changed to increase or decrease engine RPMs is the amount of fuel injected into that constant air. The more fuel the higher the RPMs less fuel lower RPMs simple as that. A faulty MAF will cause the ECU to throw a sicky because the ECU is receiving signals it does not understand which maybe out of range of the mapped data. MAF sensors came in on diesels with EU level 2 emissions regulations were a feedback of the amount of exhaust gas being ingested was required to minimise soot production. With level 3 which the TD4 uses a much tighter EGR control came into being where the amount of exhaust gas ingested was more finely controlled to reduce Nox even further. So any malfunctioning MAF will cause running problems as will any other malfunctioning sensor. Level 4 emissions regulations use an even tighter control of exhaust gas ingestion very close to minimal air needed for combustion to reduce Nox even further. This can cause soot generation so a particle filter was introduced to collect the soot and burn it off at higher engine speeds. You can't throw soot out in town but it's ok to do it at high speed with elevated exhaust temps on the motorway.

Click to expand...

My god, it is babbling about MAP sensors now and boost - WHY ??? - he needs to understand the basics first. Air in the cylinders is NEVER constant old man - and no, I am certainly not confusing Otto' engines as opposed to Compression ignition ones. Jeez
The MAF is a primary source of fuel control on this engine - as I said, please learn and stop babbling on for criz sake.
The below data is probably absolutely wasted on your pig headed self -
I do not understand which part of "Determine the correct fuel quantity to be injected" you fail to understand - or, the faulty maf symptoms, or iat symptoms (which make up the MAF as a MASS sensor) - ooooo, black smoke... (over fuelling) Oooo crappy performance - but by god ! ???? - according to you these cannot happen !!! - all you need to do is know the air in the cylinder at idle and thats it - simply inject a bit of fuel in multiples of as the quantity will remain the same per cycle - utter garbage. ...... err yes, but certainly not because - as you laughingly try to use as a catch all

this - LMFAO
"A faulty MAF will cause the ECU to throw a sicky because the ECU is receiving signals it does not understand which maybe out of range of the mapped data"
which is dummy speak for "it doesn't work without it and I do not know why" - It is like saying "if you break a wire the electrons fall on the floor".
You are digging yourself deeper and deeper and are too pig headed to realise.

Joe_H said:

My god, it is babbling about MAP sensors now and boost - WHY ??? - he needs to understand the basics first. Air in the cylinders is NEVER constant old man - and no, I am certainly not confusing Otto' engines as opposed to Compression ignition ones. Jeez
The MAF is a primary source of fuel control on this engine - as I said, please learn and stop babbling on for criz sake.
The below data is probably absolutely wasted on your pig headed self -
I do not understand which part of "Determine the correct fuel quantity to be injected" you fail to understand - or, the faulty maf symptoms, or iat symptoms (which make up the MAF as a MASS sensor) - ooooo, black smoke... (over fuelling) Oooo crappy performance - but by god ! ???? - according to you these cannot happen !!! - all you need to do is know the air in the cylinder at idle and thats it - simply inject a bit of fuel in multiples of as the quantity will remain the same per cycle - utter garbage. ...... err yes, but certainly not because - as you laughingly try to use as a catch all

this - LMFAO
"A faulty MAF will cause the ECU to throw a sicky because the ECU is receiving signals it does not understand which maybe out of range of the mapped data"
which is dummy speak for "it doesn't work without it and I do not know why" - It is like saying "if you break a wire the electrons fall on the floor".
You are digging yourself deeper and deeper and are too pig headed to realise.

View attachment 106936 View attachment 106937

Click to expand...

Think if you care to read my posts i have already said this. A faulty MAF can cause the ECU to get confused. But i will go along with you, what is the ideal fuel mixture ratio for a diesel engine that this magical MAF sensor maintains due to airflow through it?

Nodge68 said:

I read the thread but couldn't be bothered to get involved in that one.
There's only so much you can teach an old dog.
I'm waiting for him to try proving black is white because that's the loonicy I'd expect.
He definitely has trouble reading, and understanding. My I should use a font he might recognise?
Maybe Times New Roman would get the message through?

Click to expand...

Hi IS trying to prove black is white - I am longingly awaiting him getting flattened on a Zebra crossing.......................
Moron....

Now he is trying to bring in camshaft profiles, next it will be tuned intakes / headers, port mods etc (which is another subject he will know bugger all about no doubt!) - I bet you could educate him on the use of your flow bench when you were actively developing and testing such systems - but of course he will not know you had such skills and experience ? - OMG . !!! .
It is TD4 Diesel.

wammers said:

Think if you care to read my posts i have already said this. A faulty MAF can cause the ECU to get confused. But i will go along with you, what is the ideal fuel mixture ratio for a diesel engine that this magical MAF sensor maintains due to airflow through it?

Click to expand...

The magical figure is determined by the manufacturer and is contained in maps in the ecu old man - to accurately USE the figure as mapped, the ecu NEEDS to know the ACTUAL MASS of the air entering. - that is WHY the MAF is there - there is no other way on the TD4 common rail that it could be determined..... - Simple just like you.

the diesel engine does not operate in a constant stoichiometric range as does an Otto unit - I can quote some average figures if you like ?

wammers said:

But i will go along with you

Click to expand...

Well, I am impressed - a breakthrough at last. Perhaps you are not so pig headed after all

Joe_H said:

The magical figure is determined by the manufacturer and is contained in maps in the ecu old man - to accurately USE the figure as mapped, the ecu NEEDS to know the ACTUAL MASS of the air entering. - that is WHY the MAF is there - there is no other way on the TD4 common rail that it could be determined..... - Simple just like you.

Click to expand...

What a load of bollocks. The engine speed of a diesel is controlled by the amount of fuel injected it doesn't matter if it's conventional injection or common rail they all work the same way. EDC uses a map to determine the maximum amount that can be injected for variable manifold pressures, throttle demands, power demands and loads. You really are clueless.

wammers said:

Bull****. Think you had better read up on valve overlap and scavenging. Have you never heard the saying "Coming on the cam". You do talk some bloody tripe.

Click to expand...

It's a diesel were talking about. The cam timings are optimised for high, low Rpm torque and so have very short overlap periods with limited scavenging. Now if you want to talk about long duration cams or large valve overlaps and what effect they have. Sure, go ahead, I'm slightly more qualified to explain the complexities of engine turning than you my friend. It's far more complex than just long duration cams. Valve to port area and port velocity as well as valve shrouding and a million other factors come into play. I know this through trial and error so my experiences are real, in the real tuning industry. Not something that you read in a book once.
Now if you want to make yourself look stupid, go right ahead.

Joe_H said:

Well, I am impressed - a breakthrough at last. Perhaps you are not so pig headed after all

Click to expand...

Only for the sake of him explaining what he thinks is the ideal fuel to air mixture ratio for a diesel engine. He couldn't answer. And neither can you.