Replacing AAP sensor.

[Tim4x4]

Hi,
Has anyone had to replace their AAP sensor on an early TD5.
The part number is MHK100600. Land Rover main dealer says no-longer available but pointed me towards a local independent dealer for MG Rover parts, using the same part number I obtained a new AAP sensor identical to the one removed but they sell this part for a Mini.
The above was a number of weeks ago when I was having problems with my TD5 starting and poor running fitting the new AAP sensor made no difference to the running or starting issue I had.
I have since cured the starting and greatly improved the running (new wiring for the crankshaft sensor and a new fuel regulator.
The vehicle still not 100% as it hesitates like poor fueling at 45 to 50 MPH otherwise running good.
In trying to eliminate this 45 to 50 MPH issue I have looked at just about everything, including extended runs viewing live data on a Hawkeye Diagnostic reader to no avail.
I decided to go back to basics and to see what I had changed and the first thing I did was to re-fit the original AAP sensor. Straightaway an instant result the engine pulled better, has far more torque and has not hesitating at the 45 to 50 MPH range. So the original AAP sensor did not require replacement, I did not notice the problem with the new AAP sensor because the fuel regulator and the wiring for the crankshaft sensor issues masked the problem AAP sensor.
Now my question:- Is the new AAP sensor from an MG Rover dealer sold for a Mini fitment not suitable for a TD5 or is the new AAP sensor faulty?

 

[neilly]

Not sure if it makes a difference , but MHK100600L is available from most of the usual suspects.

Cheers

 

[Tim4x4]

Not sure if it makes a difference , but MHK100600L is available from most of the usual suspects.

Cheers

Now that has confused me further I have contacted my local main dealer who confirmed the Part number to be MHK100600L and not what I purchased MHK100600 (thanks neilly) my mistake but the one fitted to mine now is MHK100600 and it is running well.
They don't have to programmed to the ECU like the injectors do they? I know they each have a unique number stamped on the label but I thought this was a serial number.

 

[neilly]

I would hazard a guess as I cannot see anyway to program them that they are plug and play.

It does appear that MHK100600 does pull up a mini part, but MHK100600L appears to be a LR part.

Why would the LR dealer tell you it is not available and not say " sorry geezer, what you need it MHK100600L" as that is the correct part?.
Does your LR dealer provide that one?

Cheers

 

[neilly]

my mistake but the one fitted to mine now is MHK100600 and it is running well.

Have you put it on diagnostics, with live data readout?

Is this a case of the "new mini" one worked but gave spurious info to the ECU, but the old one now fitted is broken and the ECU is working on a std program because it is not getting a signal from it, similar to what a MAF sensor does if it fails.

Cheers

 

[Tim4x4]

I would hazard a guess as I cannot see anyway to program them that they are plug and play.

It does appear that MHK100600 does pull up a mini part, but MHK100600L appears to be a LR part.

Why would the LR dealer tell you it is not available and not say " sorry geezer, what you need it MHK100600L" as that is the correct part?.
Does your LR dealer provide that one?

Cheers

NO main LR dealer says he cannot get them supplied from Land Rover he has confirmed the Part number is MHK100600L and that it is not available.
OK he pointed me toward an independent MG Rover dealer with the part number MHK100600 and that is what they supplied, I have now contacted the MG Rover dealer for part number MHK100600L but they are unable to supply (I am not surprised).
My next question is do the genuine MHK100600L parts have that on the label?

 

[Tim4x4]

Have you put it on diagnostics, with live data readout?

Is this a case of the "new mini" one worked but gave spurious info to the ECU, but the old one now fitted is broken and the ECU is working on a std program because it is not getting a signal from it, similar to what a MAF sensor does if it fails.

Cheers

Yes that could be the case I just do not know.
Not really wanting to spend £250.00 to find that the one currently fitted is good.
I suppose I can disconnect the sensor and see how it runs if no different then I think we have it.
I will go and try it now.

 

[Tim4x4]

Ok so it runs the same with sensor connected and with sensor disconnected.
So from that do we agree faulty sensor?

 

[neilly]

Ok so it runs the same with sensor connected and with sensor disconnected.
So from that do we agree faulty sensor?

I would, but then i would stick it on my nanocom and see what it measured. The question is now, what is the difference btw the "mini" one and the "L" suffix one, if any.

Can you get it on diagnostics anywhere before you shell out for a replacement? and refit the "mini" one to see if it gives a correct reading?

Cheers

 

[Tim4x4]

I have access to a Hawkeye and have taken reading from both.
Rave says the following-
The AAP sensor is located in the top of the air filter housing. It provides a voltage signal relative to ambient air
pressure to the ECM. The AAP sensor works on the piezo crystal principal. Piezo crystals are pressure sensitive
and will oscillate in accordance to changes in air pressure. The AAP sensor produces a voltage between 0 and 5
volts proportional to the pressure level of the air in the air filter housing. A reading of 0 volts indicates low pressure
and a reading of 5 volts a high pressure.
The ambient air pressure reads the same on both but that is all I can check unless you know different.

 

[neilly]

Have you tried taking it for a drive to see what happens or if there is a difference btw the two on the same stretch of road at the same speed?

I use a nanocom and it gives a reading , plus I can save the data and review it later, can hawkeye do this?

Cheers

 

[Tim4x4]

Have you tried taking it for a drive to see what happens or if there is a difference btw the two on the same stretch of road at the same speed?

I use a nanocom and it gives a reading , plus I can save the data and review it later, can hawkeye do this?

Cheers

No I am unable to save the live data.
Am I looking at this correctly?
The AAP sensor reads Ambient Air Pressure just like a barometer it is what is prevalent due to weather conditions and altitude.
When the engine is not running and looking at live data the AAP sensor is reading the atmospheric pressure so unless I travel higher up a mountain or down to sea level it will not change the readings from the AAP sensor.
I have compared the readings from the AAP sensor and the MAP Manifold Absolute Pressure sensor and at rest all three (2 AAP sensors and 1 MAP sensor) read the same and I understand this to be atmospheric pressure so no problems there. As far as my limited knowledge goes is all I can check.

 

[bankz5152]

Why do you think its the AAP in the first place?

Any other issues, smoke, poor mpg, low power? Any fault codes cropped up?

@neilly on my phone atm can you link him to my thread on the "few fault codea after map" may be some useful info in there.

 

[neilly]

I would agree,

With the live readings I have saved the ambient air pressure does not change much during a long drive. By 1 or 2 points, The reason for the drive was to see if it somehow affects other inputs. As a comparison btw the "mini" and the one not working correctly, As you say the "mini" one does not seem to give a good drive.

What is the reading you are getting in actual air pressure, it is normally around a 100 Kpa on a nanocom.

Cheers

 

[neilly]

@bankz5152

This one then.
https://www.landyzone.co.uk/land-rover/04-defender-few-fault-codes-after-map.311606/
@Tim4x4 , this is what bankz5152 had as an issue, as he says may be worth having a read and seeing if any of it rings a bell.


Cheers

 

[Tim4x4]

Why do you think its the AAP in the first place?

Any other issues, smoke, poor mpg, low power? Any fault codes cropped up?

If you look at my first post I was having issues which I sorted (fuel regulator and crankshaft sensor wiring) except for a hesitation at 45 to 50 MPH in trying to sort the issues I replaced the AAP sensor. Now I have put back in the original sensor (going back to basics) which has cured the issue at 45 to 50 MPH.
It was suggested that the original AAP sensor could be broken and the ECU is using default readings to compensate.
I disconnected the AAP sensor and have same performance with it connected or disconnected indicating the AAP sensor could be faulty?????

 

[Tim4x4]

I would agree,

With the live readings I have saved the ambient air pressure does not change much during a long drive. By 1 or 2 points, The reason for the drive was to see if it somehow affects other inputs. As a comparison btw the "mini" and the one not working correctly, As you say the "mini" one does not seem to give a good drive.

What is the reading you are getting in actual air pressure, it is normally around a 100 Kpa on a nanocom.

Cheers

Having just made a check in the last hour 98.8kpa at rest on all three units.

 

[neilly]

Sounds about right,

Then why do you get a difference between the original one and the new one when you drive it?

Something strange is going on. Have you tried them back to back knowing that they are both giving a reading.

Cheers

 

[Tim4x4]

Sounds about right,

Then why do you get a difference between the original one and the new one when you drive it?

Something strange is going on. Have you tried them back to back knowing that they are both giving a reading.

Cheers

Yes and the new one always give poor a drive at 45 to 50 MPH. Remember that the new one is not from a LR dealer but MG Rover dealer and with a part number of MHK100600 not the MHK100600L.
My original has the part number on the label without the L.
Thanks for the link to the other posts but I have been through everything in sorting the other issues which includes the injector harness and seals, Fuel regulator, MAF, MAP, Fuel pump, Crankshaft sensor, Crankshaft sensor wiring replaced, turbo pipes, wastegate actuator, wastegate, EGR valve removed, intercooler pressure tested, inlet manifold gasket, ECM.

 

[neilly]

Yes and the new one always give poor a drive at 45 to 50 MPH. Remember that the new one is not from a LR dealer but MG Rover dealer and with a part number of MHK100600 not the MHK100600L.
My original has the part number on the label without the L.

I do remember, I am not that old yet.........

Maybe , if you know a fellow D2 owner you could be cheeky and ask to borrow theirs for a wee drive.

Cheers