Nanocom investigations (poor mpg)

If you recall, I unplugged my MAP and didn't notice any difference in performance at all. So I ordered a new one. That didn't make any difference either. So I bought a Nanocom Evolution. I checked the car for all faults in all the different modules. There weren't any so I chucked it in the boot and forgot about it. However, I'd never played with live data until this morning. So please help interpret my findings below:

Firstly, the MAP sensor.
~~~~~~~~~~~~~~~
At tick over it gives a boost reading of 101.1. At 2700 revs it gives a reading of 148.9. Whilst I don't know if that is within spec, it certainly shows a change so therefore the wiring is ok and probably the sensor is ok too.


Now on to temperature readings:
~~~~~~~~~~~~~~~~~~~~~
The water temperature started off at -11'c (it is +3 outside). It rose quickly. It was at 51'c after 10 mins of idling.

The fuel temperature started off at -15'c and after 10 mins of idling had increased to -14.4'c. Clearly not right!

The air temperature started off at -38.88'c and didn't change.



Clearly I have a temperature issue!! And therefore probably an overfueling issue as it'll go in to a default COLD program I guess.

The air temp sensor is built in to the MAF I think. But what's with the fuel being so cold and the coolant starting off cold? Where are those sensors? Could it be connected to the MAF and take their readings based on that?

I'm guessing a new MAF is the order of the day. Do you agree? Anything electrical to check first? Where's the best place to get one?

Thanks in advance

Nik

Hmm definetly an issue ther,i would change the air temps sensor first,it must be telling the pump its freezing outside and as you say chucking in loads of fuel,or not producing a lot of power!

Doesn't work that way. If the fuel is cold less is injected because it is more dense. The MAF will always show a lower temp than actual manifold inlet air temp because it is controlling the EGR.

Have you read the instructions on the edc ECM it gives you the figure for the maf and Map and what the diffrance is or should be against atmospheric pressure ecty there shouldn't be a differance of 5 kpa if iremember

defender300td1 said:

Have you read the instructions on the edc ECM it gives you the figure for the maf and Map and what the diffrance is or should be against atmospheric pressure ecty there shouldn't be a differance of 5 kpa if iremember

Click to expand...

You could have just asked me that question in Greek. No, I speak some Greek. Er, German.

What?

NikTheGeek said:

You could have just asked me that question in Greek. No, I speak some Greek. Er, German.

What?

Click to expand...

read through nancoms the edc ecu's functions intruction manuel and it will give you more info and parameters combined with the use of rave!

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Water temperature​

​

[/FONT]​

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Air temperature​

​

[/FONT]​

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Boost pressure (KPa)​

​

[/FONT]​

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Atmospheric pressure (KPa)​

​

[/FONT]​

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Throttle pot (%)​

​

[/FONT]​

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Throttle pot volts​

​

[/FONT]​

below 0.8 volts when the pedal is released and above 3.3 volts when the pedal is depressed.

defender300td1 said:

read through nancoms the edc ecu's functions intruction manuel and it will give you more info and parameters combined with the use of rave!

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Water temperature​

​

[/FONT]​

[/FONT]: The current Coolant temperature in degrees centigrade, derived from the coolant
temperature sensor.​

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Air temperature​

​

[/FONT]​

[/FONT]: The current air intake temperature in degrees centigrade, derived from the air intake
temperature sensor.​

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Boost pressure (KPa)​

​

[/FONT]​

[/FONT]: The boost pressure sensor measures inlet manifold turbo pressure and is
displayed in KPa. It should not vary from the atmospheric value by more than plus or minus 5 KPa when
not running or at idle.​

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Atmospheric pressure (KPa)​

​

[/FONT]​

[/FONT]: Current Atmospheric pressure measured in KPa, derived from the
pressure sensor.​

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Throttle pot (%)​

​

[/FONT]​

[/FONT]: The current output from the Throttle position Potentiometer calculated as a
percentage.​

[FONT=Calibri,Bold][FONT=Calibri,Bold]

Throttle pot volts​

​

[/FONT]​

[/FONT]: The current voltage output from the Throttle position Potentiometer. Should go​

below 0.8 volts when the pedal is released and above 3.3 volts when the pedal is depressed.

Click to expand...

Think his name is Nick not Manuel.

For those (like me) who had never heard of KPa......

1 Kilopascal (kPa) = 0.145037738 Psi (Pound Per Square Inch)

Kilopascal is a metric unit and equals a force of 1000 Newtons per square metre.

Pete

Ok, thanks.

Average air pressure at sea level is 101.3kpa. So that reading is correct and therefore the pressure sensor is correct. But the water sensor and air sensor are values derived directly from their respective sensors aren't they rather than "worked out". Which still leads me to ask "Is my MAF a duff'n?"

NikTheGeek said:

Ok, thanks.

Average air pressure at sea level is 101.3kpa. So that reading is correct and therefore the pressure sensor is correct. But the water sensor and air sensor are values derived directly from their respective sensors aren't they rather than "worked out". Which still leads me to ask "Is my MAF a duff'n?"

Click to expand...

The MAF measures the air temp before the turbo in order to control the EGR. The actual inlet air temp will always be higher than the MAF reading. However if the MAF has gone down the ECU will revert to a preset. If the MAF temp never changes then i would think that is what is going down.

wammers said:

The MAF measures the air temp before the turbo in order to control the EGR. The actual inlet air temp will always be higher than the MAF reading. However if the MAF has gone down the ECU will revert to a preset. If the MAF temp never changes then i would think that is what is going down.

Click to expand...

If it helps:
If I unplug the lead to the MAF, I get exactly the same reading of -38.88'c BUT, it registers a fault code in the ECU relating to Air Temp Value. If I clear the fault and plug the lead back in, same reading, but no fault stored.

So I think the wiring/electrics is ok.

I'll have to try a MAF. Where's the most reliable place to get one that won't be a cheap copy like ebay would be?

tnx

Nik

If the car has a MAF, it does not have an inlet air temperature sensor so you get a fixed reading from the non existant sensor.
Water temperature is low and I'm a bit puzzled by the fuel temperature, does not look right to me. I don't have a Nanocom or I would do a comparison with mine, if needed I will put my Faultmate on and see what fuel temperature readings I get.

Datatek said:

If the car has a MAF, it does not have an inlet air temperature sensor so you get a fixed reading from the non existant sensor.

Click to expand...

Oh, that's thrown me!

I can see that makes sense and I did always wonder how a simple heated wire could measure temperature as the readings would change depending on how much air/wind was passing over it! Does it ignore temperature then and just work on air flow?

And I'm not for a second doubting you, but if -38.88 was normal for a non-existant sensor, wouldn't there be a whole host of questions in forums showing up on a google search? There's no mention of it.

I would appreciate any one else just seeing what they get on a post 99 car. Mines a 2002. I also guess that different diagnostic machines might give different readings...

thanks all

Nik

nick on the nano it should have somewhere on the faults section values this should tell you what a sensors expected value is and weather it is too high too low ect invaled value ect your fuel temp is inside the fip and have know problem of over fueling when faulty go and check your values.

FAULTS:
The Electronic Diesel Control (EDC) has a very sophisticated system for logging faults and although it has
only 27 fault codes, for each code it logs, there is attached to it a number of flags which give much more
information about the fault, thus multiplying the effective number of different events which share the
same basic code by many times. There are also two system sensor values, which are stored as a form of
freeze frame data giving more information about the circumstances that caused the fault. The data that is
captured depends on the fault. Each code read-out of the system is presented, starting with a description
of the circuit to which the fault is pertaining, followed by the name of the first value and the value itself,
the name of the second value and the value itself, then by a list of the meanings of the flags which have
been triggered. The flag options are:
· TOO HIGH: The value from the sensor in question is / was above accepted limits.
· TOO LOW: The value from the sensor in question is / was below accepted limits.
· OPEN CIRCUIT: The sensor in question was not detected in its wiring loop.
· INVALID VALUE: The value from the sensor in question is / was not a sensible or possible value.
· MAJOR FAULT: A fault that can prevent the engine from running and requires immediate attention.
· FAULT LOGGED: A fault which causes no adverse or noticeable affect, but never the less has been
seen.
· CURRENT: Where the fault is actually there now as opposed to having been there and not being
there when the fault memory is read.
· INTERMITTENT: Where the fault in a sensor has been seen and logged on one occasion, then the
sensor has been accepted as working OK, and then goes faulty and the cycle repeats.
It is important to remember these 8 attached flags, because they are only listed if they are set and the fact
that they are missing will give you as much information as if they are resident, helping you locate the
source of the problem. i.e. the fact that the fault is continuously there, is denoted by the absence of the
intermittent flag. Important information is a count of the number of times the system has detected the
fault on system power up. It is also worth noting that when the vehicle is not fitted with Cruise Control the
EDC ECU logs this fact as a fault with the cruise control, which because it is not a major fault is ignored.
Clear faults:
This function first reads the fault code memory to ensure that there are faults to clear and if there are
completely erases and clears the fault code memory. Having deleted the faults it then re-checks the fault
memory to check that it is clear, reporting success if it is. Failure to clear the fault memory successfully is
usually due to the system re-logging the fault the moment the fault memory is clear. This indicates that the
fault has not been rectified properly and as far as the system is concerned, still exists. The re-check for
successful clearing of the fault code memory may pass but then the system may re-log the fault shortly

NikTheGeek said:

If it helps:
If I unplug the lead to the MAF, I get exactly the same reading of -38.88'c BUT, it registers a fault code in the ECU relating to Air Temp Value. If I clear the fault and plug the lead back in, same reading, but no fault stored.

So I think the wiring/electrics is ok.

I'll have to try a MAF. Where's the most reliable place to get one that won't be a cheap copy like ebay would be?

tnx

Nik

Click to expand...

You have been on about low fuel consumption for a long time. What exactly is you average consumption and daily mileage? Also if you have disconnected the MAP sensor and not noticed a fundamental difference in engine power something is badly wrong somewhere. The MAF does not control fuelling it measures the air temp and therefore density and controls how much exhaust gas is needed to be released into the manifold by the EGR valve to reduce the Oxygen content of the charge to cool combustion and reduce NOX production. It is there for finer control of the EGR. As the presence of exhaust makes the combustion less efficient a slight drop in RPM will occur, sensed by the crank sensor fuel will be increased to compensate.

wammers said:

You have been on about low fuel consumption for a long time. What exactly is you average consumption and daily mileage? Also if you have disconnected the MAP sensor and not noticed a fundamental difference in engine power something is badly wrong somewhere.

Click to expand...

3-4 miles a day when my wife uses it. Averaging 15-16 mpg. When I take it on a run at a steady 65-70, it will return around 20 - anywhere between 19-21.

It's my first Range Rover so I don't have a benchmark to compare it too but unplugging either the MAP or MAF makes no noticable difference to mpg or performance. I don't think the performance is too bad anyway. It'll tow a double horsebox fully loaded fine. It goes up hills ok. Kicks down and goes for it when you plant the throttle. So all seems fine apart from mpg. But honestly, unplugging the map makes no difference.

I'll give up and stop worrying about it...

Nik

Datatek said:

Water temperature is low and I'm a bit puzzled by the fuel temperature, does not look right to me.

Click to expand...

After taking it for a run, the figures are wholly different. Water is up at 88 as you'd expect and the fuel is at +14'c now. It's 2'c outside. So the fuel has warmed.

It's the first time I've used the Nanocom to read live data. Maybe it needed to think for a while. Either that or I didn't realise just how cold it was last night!!

Nik

NikTheGeek said:

3-4 miles a day when my wife uses it. Averaging 15-16 mpg. When I take it on a run at a steady 65-70, it will return around 20 - anywhere between 19-21.

It's my first Range Rover so I don't have a benchmark to compare it too but unplugging either the MAP or MAF makes no noticable difference to mpg or performance. I don't think the performance is too bad anyway. It'll tow a double horsebox fully loaded fine. It goes up hills ok. Kicks down and goes for it when you plant the throttle. So all seems fine apart from mpg. But honestly, unplugging the map makes no difference.

I'll give up and stop worrying about it...

Nik

Click to expand...

Unplugging the MAP sensor HAS to make a difference to engine power without it you are not getting boost fuel. In town stop go in traffic in a hilly area heavy throttle use when pulling away short journeys 16 MPG is all you are going to get. You should however get 25+ on a run over 50 MPH. As i believe i have said before, get on the M6 and reset you computer as you go down the slip road, go to Preston at 60-70 MPH and then go back you should be getting 25+ no problems. How it is driven makes a big difference. I can get mine down to 15-16 MPG if i boot it everywhere. Driven normally 18 round town, 25 to 28 on a run say to Scotchlandia.

My DSE returned 25.6mpg with a good mix of driving. Worst was about 20 and best 27. As Wammers says the MAP should make a difference when it is unplugged!

If the MAF is faulty, the EDC defaults to fixed fueling maps, performance is down and fuel consumption is up, at least that's the way it is on mine.