Range Rover P38 Sluggish / no power

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It does change it's set points periodically with regards to fuel mappings, but I am not sure if the MAF affects these or not, as the MAF on the Diesel isn't there to regulate Fuelling the EDC (Electronic Diesel Control) does that....

The MAF doesn't regulate engine power, like it does in a petrol engine, as a petrol system needs to know how much and how dense the air is inorder to deliver the correct amount of fuel to create an even and efficent burn depending on engine loads, speeds etc...

In a Diesel, there is no throttling of the air to dictate power output, it is purely controlled by the amount of diesel injected....the air is just sucked (or in the case of a turbo pushed) into the cylinders to permit the diesel oil to burn...

The MAF only tells the EGR system to include a certain amout of exhaust recircluated air as the incoming air temperature and density is such that when it gets burnt, it will create to much emissions, so please introduce some hot gasses to reduce the combustion temperature to fully burn the oil and air mixture in order that the exhaust will pass the emission standards....

The MAF has no effect on fuelling, that is the role of the EDC and FIP.
 
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Saint.V8 said:
It does change it's set points periodically with regards to fuel mappings, but I am not sure if the MAF affects these or not, as the MAF on the Diesel isn't there to regulate Fuelling the EDC (Electronic Diesel Control) does that....

The MAF doesn't regulate engine power, like it does in a petrol engine, as a petrol system needs to know how much and how dense the air is inorder to deliver the correct amount of fuel to create an even and efficent burn depending on engine loads, speeds etc...

In a Diesel, there is no throttling of the air to dictate power output, it is purely controlled by the amount of diesel injected....the air is just sucked (or in the case of a turbo pushed) into the cylinders to permit the diesel oil to burn...

The MAF only tells the EGR system to include a certain amout of exhaust recircluated air as the incoming air temperature and density is such that when it gets burnt, it will create to much emissions, so please introduce some hot gasses to increase the combustion temperature to fully burn the oil and air mixture in order that the exhaust will pass the emission standards....

The MAF has no effect on fuelling, that is the role of the EDC and FIP.
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We'll just have to agree to disagree. The MAF provides an accurate measurement to the EDC of the air being sucked/shoved into the engine, the EDC uses this to control the FIP to closely regulate the fuel being injected at any given throttle opening/revs/load thus reducing emissions, it is also used along with other sensors to compute when the EGR can operate also in the interests of reduced emissions. Diesels often used to smoke on wide throttle openings at low revs/high load due to poor regulation and excess fuel being injected, the MAF allows the ECU to effectively limit the fuel injected to the amount required for a clean burn regardless of throttle/revs/load.
 
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Datatek said:
We'll just have to agree to disagree. The MAF provides an accurate measurement to the EDC of the air being sucked/shoved into the engine, the EDC uses this to control the FIP to closely regulate the fuel being injected at any given throttle opening/revs/load thus reducing emissions, it is also used along with other sensors to compute when the EGR can operate also in the interests of reduced emissions. Diesels often used to smoke on wide throttle openings at low revs/high load due to poor regulation and excess fuel being injected, the MAF allows the ECU to effectively limit the fuel injected to the amount required for a clean burn regardless of throttle/revs/load.
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Agreed...:D:D

All I know is mine has it and without it it doesn't work properly no matter what the MAF does...!!!:)
 
Saint.V8 said:
Agreed...:D:D

All I know is mine has it and without it it doesn't work properly no matter what the MAF does...!!!:)
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Saint.V8 - the answer here is all in your name as far as im concerned..

as in stick with a V8 in a range rover not some hybrid beemer diesel lump instead

else mankind will be arguing about the air flow/ fuel ratios of their Prius powered Ferrari F680's in years to come..

Its only a Range Rover if it's a V8 under the hood, nothing more nothing less.. and i say this as an owner of one for all of 6 weeks, one that wouldnt start today and has had a new battery as its reward.

To V8 petrol owners i say..:praise:
To diesel owners i say... :mooning:
 
Pdirty8 said:
Saint.V8 - the answer here is all in your name as far as im concerned..

as in stick with a V8 in a range rover not some hybrid beemer diesel lump instead

else mankind will be arguing about the air flow/ fuel ratios of their Prius powered Ferrari F680's in years to come..

Its only a Range Rover if it's a V8 under the hood, nothing more nothing less.. and i say this as an owner of one for all of 6 weeks, one that wouldnt start today and has had a new battery as its reward.

To V8 petrol owners i say..:praise:
To diesel owners i say... :mooning:
Click to expand...
If you take a peek at my signature and read some of previous posts, my 4 previous Rangies have been V8's....

Yes my current is a Diesel, for good reason - Cost...yes I prefer a V8, who doesn't, but when I have to get into my Diesel Range Rover to pull a soaked V8 with water in the ignition components out of the drink, I do have a wry smile on my face.

I also like the fact I no longer have to worry about slipped liners, fractured coil packs, BeCM losing sync every weekend, knackered lambda sensers, over complex injection systems or leaking valley gaskets.

I only have to fil it with diesel at one end and coolant in the other.

The Diesels have their faults I admit, as do the ppetrols, but please do not cast assumptions to my choice of Range Rover just because it doesn't have a V8....not as much grunt I grant you, but equally as capable.
 
once again data i agree the maf provides information as to how much air is being drawn into the engine yes for egr and also for fueling!!!!!!
i know everyone is entilted to there opinions but if you actually google the purpose of a maf in a diesel even the patents listed show the information and agree with you and me!!!
 
Davlyn said:
whilst you all slog it out over who is right and who is wrong can somebody tell me te best way to clean the EGR out?

thanks,

Dave
Click to expand...
You could try petrol or parrafin...a good hydrocarbon solvent....and a good brush....make sure all solvents are cleared out, and left to dry throughly before fitting back again, the last thing you want is a flammable solvent left in it...
 
Datatek said:
We'll just have to agree to disagree. The MAF provides an accurate measurement to the EDC of the air being sucked/shoved into the engine, the EDC uses this to control the FIP to closely regulate the fuel being injected at any given throttle opening/revs/load thus reducing emissions, it is also used along with other sensors to compute when the EGR can operate also in the interests of reduced emissions. Diesels often used to smoke on wide throttle openings at low revs/high load due to poor regulation and excess fuel being injected, the MAF allows the ECU to effectively limit the fuel injected to the amount required for a clean burn regardless of throttle/revs/load.
Click to expand...
Thanks D, seems like my Diesel knowledge is a decade out of date then...!!!:eek:

I doff my cap to thee once again....
 
shortened version of how a maf works in a diesel!
1. the maximum fuel quantity that can be injected at any given revs is contained within fuel maps. these values are determined by the vehicle manufacturer to tailor the torque curve taking into account engine and transmission power rating, emissions req, poor servicing, poor fuel.
2. the max amount is modified by the ecu based onvarious sensor signals before being sent to the pump ecu.
3.the crucial one is throttle position signal clearly the ecu uses this to adjust the fuel quantity from allmost zero to the maximumit is programmed to supply at any given rpm.
4.THE SIGNAL FROM THE MAF SENSOR IS ALSO USED TO ADJUST THE FUEL DEPENDING UPON THE MASS OF AIR GOING INTO THE ENGINE.
5. on a turbo engine the airflow depends on boost pressure as well as rpm. and there is a surplus of air once the turbo starts to work. the fuelling can then be determined by the fuel maps. and the maf sensor is somewhat less crucial.
6. BELOW 1800-2000RPM HOWEVER WHEN THE TURBO IS BARELY WORKING THERE IS NOT A SURPLUS OF AIR AND TO AVOID SMOKE AND TO COMPLY WITH EVER TIGHTER EMISSIONS REGS AIR FLOW MUST BE MEASURED.
7. CONSEQUENTLY IF THE MAF SIGNAL IS BELOW PAR, THE FUEL QUANTITY NEVER REACHES THE MAX ALLOWED AND THUS TORQUE IS REDUCED.
this is how a maf works in a diesel, cant see i can add anymore to the argument!
 
6704nathan said:
once again data i agree the maf provides information as to how much air is being drawn into the engine yes for egr and also for fueling!!!!!!
i know everyone is entilted to there opinions but if you actually google the purpose of a maf in a diesel even the patents listed show the information and agree with you and me!!!
Click to expand...

6704nathan said:
shortened version of how a maf works in a diesel!
1. the maximum fuel quantity that can be injected at any given revs is contained within fuel maps. these values are determined by the vehicle manufacturer to tailor the torque curve taking into account engine and transmission power rating, emissions req, poor servicing, poor fuel.
2. the max amount is modified by the ecu based onvarious sensor signals before being sent to the pump ecu.
3.the crucial one is throttle position signal clearly the ecu uses this to adjust the fuel quantity from allmost zero to the maximumit is programmed to supply at any given rpm.
4.THE SIGNAL FROM THE MAF SENSOR IS ALSO USED TO ADJUST THE FUEL DEPENDING UPON THE MASS OF AIR GOING INTO THE ENGINE.
5. on a turbo engine the airflow depends on boost pressure as well as rpm. and there is a surplus of air once the turbo starts to work. the fuelling can then be determined by the fuel maps. and the maf sensor is somewhat less crucial.
6. BELOW 1800-2000RPM HOWEVER WHEN THE TURBO IS BARELY WORKING THERE IS NOT A SURPLUS OF AIR AND TO AVOID SMOKE AND TO COMPLY WITH EVER TIGHTER EMISSIONS REGS AIR FLOW MUST BE MEASURED.
7. CONSEQUENTLY IF THE MAF SIGNAL IS BELOW PAR, THE FUEL QUANTITY NEVER REACHES THE MAX ALLOWED AND THUS TORQUE IS REDUCED.
this is how a maf works in a diesel, cant see i can add anymore to the argument!
Click to expand...
As I said to D earlier, obviously my Diesel knowledge is a bit behind:eek::eek:....so thanks for the schooling, looks like I am going to have to stop designing Aircraft Gas Turbine components and Service Equipment and pick up a Bosch Diesel Injection for Dummies book instead lol....:D
 
i only know this from past experience and research when in my younger days tuning an L SERIES diesel engine in the rover 25 (same as freelander) got upto nearly 170bhp with various mods.
and having seen the effects of boosting the maf signal the improvements in off boost situations and low speed throttle responses
 
4.THE SIGNAL FROM THE MAF SENSOR IS ALSO USED TO ADJUST THE FUEL DEPENDING UPON THE MASS OF AIR GOING INTO THE ENGINE.
5. on a turbo engine the airflow depends on boost pressure as well as rpm. and there is a surplus of air once the turbo starts to work. the fuelling can then be determined by the fuel maps. and themaf sensor is somewhat less crucial.
6. BELOW 1800-2000RPM HOWEVER WHEN THE TURBO IS BARELY WORKING THERE IS NOT A SURPLUS OF AIR AND TO AVOID SMOKE AND TO COMPLY WITH EVER TIGHTER EMISSIONS REGS AIR FLOW MUST BE MEASURED.

Think this covers things nicely. And is just what i said earlier. The MAF is there to drive the EGR at low engine speed when the engine is cold to reduce emissions.
 
WOW these facts and figures are all too much for a numpty like me - lots of clever people on here - great to see - by the way i hope I'm not doing any damage to the lump under the bonnet running without the maf plugged in ( whilst waiting for the replacement to come ) BUT ITS GOING REALLY REALLY NICE..:car:.hope it still goes as well when the replacement is fitted..
 
softop2011 said:
WOW these facts and figures are all too much for a numpty like me - lots of clever people on here - great to see - by the way i hope I'm not doing any damage to the lump under the bonnet running without the maf plugged in ( whilst waiting for the replacement to come ) BUT ITS GOING REALLY REALLY NICE..:car:.hope it still goes as well when the replacement is fitted..
Click to expand...

Don't think you will do any damage to engine although you may kill a few people. Did you try connecting MAF and disconnecting the EGR? :D:D:D
 
ummmm no - hope this doesn't mean waste of £60 on a maf - or having to buy en egr modulator valve - gonna give it a try NOWWW -see how it goes:crazy_driver:
 
wammers no one has disagreed that maf controls egr, but i think you were saying maf has nothing to do with fuel? which it does!
dont waste your time messing with egr valve replace maf and all will be well!!!!
 
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