Nodge68 said:
This statement is incorrect. A non turbo engines swept volume is very different from static to flat out. It's ability to fill the cylinders is completely based on many factors. This is known as the engine's Volumetric Efficiency (VE). So in simple terms an engine of 500cc static volume won't fill the cylinders with 500cc of air when turning at 4700 Rpm. So the fuelling must to compensated to take this into account.

The MAF sensor on a modern diesel is as important for fueling as any other sensor on the engine. Things have moved on ;)
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I just knew you would come up with that. It was a general statement not a bloody F1 tuning lecture. How does the swept volume change at different engine speeds?
 
Next time I need to look up egotistical in the dictionary I will know where to look under Wammers.

Thanks to everybody who made a suggestion or an insight to the problem

Lap top does not work well it works but I cant make head nore tail of it , will start checking all the turbo tubes again guy from the local garage has a maf I can borrow to see if it makes a difference and is bringing his code reader so fingers crossed.

thanks again boys
 
Diesel Do said:
I'm saying you clearly aren't interested in anything other than your opinion. You won't listen. You won't take on board any evidence presented to you. So based on that its pointless arguing with you. Land Rover themselves can tell you you're wrong and you wouldn't accept it. We've both been here before as have many others. It's pointless. You're happy in your world with your old fashioned diesels where you're quite right. But whether you like it or not things have moved on. I'm not going to explain it again as you really aren't interested. Go back and read the posts and links. They aren't fabricated to wind you up. It's documented fact.
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I was wondering when some one would have had enough

Diesel Do said:
Ignoring the in fighting:D is your EGR blanked, working or broken?
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Its been blanked of for about 3 years african style 22mm copper end cap inserted into the entry of EGR body.
 
I've had a bad day :D

It's not that then unless it's rotted? Not sure if it would in that environment. But probably worth a look.
 
sorea said:
Next time I need to look up egotistical in the dictionary I will know where to look under Wammers.

Thanks to everybody who made a suggestion or an insight to the problem

Lap top does not work well it works but I cant make head nore tail of it , will start checking all the turbo tubes again guy from the local garage has a maf I can borrow to see if it makes a difference and is bringing his code reader so fingers crossed.

thanks again boys
Click to expand...

You will be shocked when the search comes up with knowledgeable. ;)
 
fredi250 said:
No you have it wrong I pay other people to be mechanically adept so no way would I employ someone that was so behind on modern technology.
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I understand what they suggest is not possible. You don't know enough to question that. Fortunately i do. You may or may not be interested to learn that the MAF operation on the M51 engined P38 is described in similar text. That is also incorrect.
 
wammers said:
Please let him tell us how the swept volume changes i am dying to know. :D
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Easy, it changes depending on the amount of wear on the big end bearings. The more wear, the lower the swept volume.

However, the effective swept volume, which is indicated by the amount of gas pulled into the engine does change, depending on engine rpm, valve timing, and manifold efficiency.

And as the effective swept volume determines the maximum amount of fuel which should be injected and the timing of the injection, it is important for anything other than a fairly crude diesel engine.
 
Hope the OP has got what he wanted out of the thread :)

However, this is a thread that just keeps on giving and is truly entertaining and somewhat educational.

After much research I have found that for many years British diesel engines did not use the MAF when calculating the quantity of fuel to inject. This was instigated by Rover engineers attempting to create a diesel conversion of the Turbo K Series engine. They determined that the MAF was not a suitable candidate for determining how much fuel to inject as they couldn't tell how much of the air going through the MAF ended up in the cooling system.

That's honest guv - it was on Wiki - so got to be true.
 
Tony Reeves said:
Easy, it changes depending on the amount of wear on the big end bearings. The more wear, the lower the swept volume.

However, the effective swept volume, which is indicated by the amount of gas pulled into the engine does change, depending on engine rpm, valve timing, and manifold efficiency.

And as the effective swept volume determines the maximum amount of fuel which should be injected and the timing of the injection, it is important for anything other than a fairly crude diesel engine.
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Do keep up, he said the swept volume changed as revs increased. It can't. It is very easy to know when someone knows what they are talking about, sadly you and many others on this thread don't. Maybe you want to have a further think about the statement in your first sentence. Clutching and straws come to mind. Diesel engines are fuelled subject to power request, not subject to airflow through a MAF. Increased airflow through the MAF is a result of the engine speed increasing as the ECU increases fuel to satisfy a given driver power request. The MAF sensor on diesels with tight emission control does play a part in that emission control. But it does not run the engines general fuelling regime. Readings from it will certainly cause the ECU to interfere with fuelling from time to time under certain conditions. But the idea that a MAF sensor fitted to a diesel works in the same way that a petrol MAF and fuel system work is ridiculous. There is ALWAYS more air in a diesel cylinder than the engine needs to burn the fuel. If you want a diesel to run faster you inject more fuel if you want it to slow down you inject less. Air is constant. The only thing the ECU needs to know on engines with variable turbos etc, is that there is sufficient air to clean burn the fuel needed for the power requested.
 
GrumpyGel said:
Hope the OP has got what he wanted out of the thread :)

However, this is a thread that just keeps on giving and is truly entertaining and somewhat educational.

After much research I have found that for many years British diesel engines did not use the MAF when calculating the quantity of fuel to inject. This was instigated by Rover engineers attempting to create a diesel conversion of the Turbo K Series engine. They determined that the MAF was not a suitable candidate for determining how much fuel to inject as they couldn't tell how much of the air going through the MAF ended up in the cooling system.

That's honest guv - it was on Wiki - so got to be true.
Click to expand...

Wammers is sort of right but 20 years out of date.
A diesel does actually need more fuel to make more torque. In the past (L series for example) the fuel pump simply throws in enough fuel to make the given torque output. This was fine as the restrictions allowed an amount of black smoke to be produced at full power.
However on the EU3 spec engine, black smoke and NOX emissions are much reduced. So to counter the black smoke issue, the ECU will actually limit the fuel flow to the cylinders, if there's insufficient air to achieve a clean burn. This is why a week MAF signal limits torque so much. The ECU sees a low signal and incorrectly limits fuel. If the MAF signal is outside a set parameter, the ECU substitutes a default setting based on throttle position, engine load via the MAP and engine speed. This substituted parameter does generally produce black smoke as fueling is incorrect.
So on the TD4, and all other EU3 and later diesels, the MAF signal is very important to the way the engine runs.
EU2 engines simply use the MAF as a feedback for when the EGR is open. This is much less complicated and so the MAF can be removed with no effect on the way the engine runs. Providing the EGR has been removed.
The EU3 engine uses the same MAF signal feedback for EGR operation as well as the fuel limiting strategy described above.
 
Funny thing is Wammers you contradict yourself volume of air isn't constant. You've got a turbo. How can it be? That means there will be be a pretty big change in air flow depending on throttle position, vane position that kinda stuff so maybe the ecu wants to know this so it doesn't over fuel and kill kittens :D
 
Diesel Do said:
Funny thing is Wammers you contradict yourself volume of air isn't constant. You've got a turbo. How can it be? That means there will be be a pretty big change in air flow depending on throttle position, vane position that kinda stuff so maybe the ecu wants to know this so it doesn't over fuel and kill kittens :D
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The volume of air in the cylinders changes with engine speed anyway DD. Even before the turbo is taken into consideration. Air has a mass and like water flowing through a pipe, can only get so much into the cylinder in the operating cycle. So if you were to turn an engine slowly by hand. The cylinder would indeed fill with say 500cc of air. However spin that engine over at 4000 Rpm and suddenly 500cc of air can't get into the cylinder as the ports, valves, guides and other restrictions prevent it. So the cylinder ends up with only 450cc of air in the cylinder. This difference is called the Volumetric Efficiency or VE. Turbocharging actually forces air into the cylinders over and above the static volume. So the same 500cc cylinder can receive 600 or more ccs of air. This makes a huge difference to the torque an engine can produce at times of boost. So the engine design can be optimised for off boost torque production, with the boosted air improving high Rpm torque ability.

The MAF is used to tell the ECU how much air is in the cylinders, so the correct amount of fuel is added. Keeping in mind that black smoke production must be kept in check.
 
Diesel Do said:
Funny thing is Wammers you contradict yourself volume of air isn't constant. You've got a turbo. How can it be? That means there will be be a pretty big change in air flow depending on throttle position, vane position that kinda stuff so maybe the ecu wants to know this so it doesn't over fuel and kill kittens :D
Click to expand...

You are starting to get a bit silly. Look at my other posts "For any given power request, RPM, manifold pressure air is constant". You are supposed to be a mechanic i feel sorry for your customers. I have already covered all you mention in previous posts. Now who is not reading what is written.
 
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