Thread: ambient intake temp td5

Originally Posted by landroverjack

where does the nanacom get its ambient inlet temperature from???

It doesn't.

Somehow Mattias and then BBS forgot to give the Nanocom the ability to read and display the reading from the Ambient Air Temp sensor which is part of the Ambient Air Pressure sensor located on the Airbox on EU3 engined Td5's.

What the Nanocom does display in the Fuelling section is Inlet Air Temperature which is the reading from the Inlet Manifold. The IAT is combined in the same housing as the Manifold Absolute Pressure sensor. It's often called the MAP/IAT.

cheers
Paul

Your reading a tempreture that is turbo forced by your exhaust even tho its intercooled it will be higher than the ambient temp

MAF hits good numbers, boost is around the 211kilo pascols, which is around a peak of 30psi with no over boost has a BD chip installed. What I thought was a bit odd was the ambient intake temperature. Almost from start up and certainly when warmed up is showing around the 102 degree mark.

Nanocom displays Manifold Absolute Pressure, so pressure referenced to a small vacuum reservoir in the sensor. So the 211 is absolute pressure not boost. You'd need to subtract the ambient pressure reading to find boost. At sea level it's around 101kpa, so you are getting about 110kpa boost or 16psi.

Your IAT reading is very high. Even if the car is a dark colour and has been sitting in full sun all day it is high. I'd investigate further.

cheers
Paul

The AAP sensor is located in the top of the air filter housing.
It provides two voltage outputs both 0<5Volts relative to both ambient air pressure and air temperature for the ECM.
Not temperature on EU2/10p engine.

Back probe the sensor wires to see the voltage the ECM gets.

Example AAP
Temperature output
green/blue 3.7volts approx 8degrees C ok reading

white/yellow 4.0 volts should be 84kpa ok reading

pink/purple 5.2 volts supply ok reading

pink/black 0 earth ok reading

This test was at approx 50meters
approx 8 degreesC engine running.


Pressure sensing first.
A reading of 0 volts indicates low pressure and a reading of 5 volts indicates high pressure.
The ECM uses the signals from the AAP sensor for the following functions:
To maintain manifold boost pressure.
To reduce exhaust smoke emissions while driving at high altitude.
Control of the EGR system.
The inlet manifold pressure sensor MAP is to give the ECM inlet pressure and temperature.
The ECM calculates the difference between the atmospheric (AAPsignal)and inlet pressures and it then knows what the actual charge pressure is.
This figure is used to inject the correct amount of fuel to suit the current engine requirement and to control boost with aid of the boost modulator.

The table below gives the voltage output expected on a good AAP sensors pressure sensor.
Use the 1bar sensor line.



Altitude Verses pressure graph



Approx figures for testing voltage output using multimeter
Air Temp C KOhms Voltage
-40 880 4.53
-30 573 4.48
-20 272 4.33
-10 183 4.20
0 95 3.87 32°F 3.897
10 66 3.55
20 38 3.10 68°F 3.09
30 27 2.70
40 16 2.10
50 12 1.8
122°F 1.72
60 7.5 1.3
70 5.6 1.05
80 3.8 0.75
90 3.0 0.60
100 2.2 0.45
110 1.6 0.35
120 1.2 0.25

Have you recently cleaned your MAP/IAT sensor if not give it a clean with contact cleaner AAP can also be cleaned the same way.
Good clean sensors give good outputs.

Hope this helps Pete

Thanks for the input fellahs.


Took out the sensor on the inlet manifold, not very dirty or oily, have a catch can and no EGR. Cleaned this up with MAF cleaner.
Took the sensor out on the air filter, this was a tiny bit dusty but otherwise quite clean, cleaned with MAF cleaner anyway.
MAf was cleaned not long ago and was giving good figures.


Went for a quick drive, no "seat of the pants" difference, I 'll put the nanacom on this weekend and see if the inlet temp comes down at all.


I know it is a 2.7t house brick and I am not 18yo so drive sensibly most of the time but I still reckon that 15l/100k economy in Sydney traffic is a bit high, last run to the farm only averaged 12l/100k over 600k's driving. It used to be much better, low 9's. Something has changed in the last 3 tanks of deiso. I guess I will just chip away bit by bit to see what is faulty, out of whack or just plain worn out.


cheers guys,
Jack

Same thing is happening with mine...

Please if u find a fix let us know...

Originally Posted by landroverjack

Thanks for the input fellahs. Took out the sensor on the inlet manifold, not very dirty or oily, have a catch can and no EGR. Cleaned this up with MAF cleaner. Took the sensor out on the air filter, this was a tiny bit dusty but otherwise quite clean, cleaned with MAF cleaner anyway. MAf was cleaned not long ago and was giving good figures. Went for a quick drive, no "seat of the pants" difference, I 'll put the nanacom on this weekend and see if the inlet temp comes down at all. I know it is a 2.7t house brick and I am not 18yo so drive sensibly most of the time but I still reckon that 15l/100k economy in Sydney traffic is a bit high, last run to the farm only averaged 12l/100k over 600k's driving. It used to be much better, low 9's. Something has changed in the last 3 tanks of deiso. I guess I will just chip away bit by bit to see what is faulty, out of whack or just plain worn out. cheers guys, Jack

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I was just talking to my mechanic earlier this week questioning the same thing, albeit mine has been more gradual. I can't believe that carrying an increasing over time load of tools in the back would make that much difference.

Originally Posted by gavinwibrow

I was just talking to my mechanic earlier this week questioning the same thing, albeit mine has been more gradual. I can't believe that carrying an increasing over time load of tools in the back would make that much difference.

Hey Fellas

Any wins re the decreased economy over time. I've also recently changed from 9.5l/100km to 15l/100km.