D4 Fuel Temp Sensor reading negative value

[TopEndThom]

Has anyone experience this before? My fuel temp seems to sit around -30deg C when I read the live value with the iiD Tool. I live in Darwin where the average ambient temp is actually about +30deg C this time of year.. ??

https://uploads.tapatalk-cdn.com/20200325/9cd4d89873245e0a03481523548e42e0.jpg

I’ve been having issues with a reduced performance and gearbox fault problem on my 2009 2.7 Disco 4. After loss of power at random times, could be cruising on flat road at 100kph or downshifting on a slight rise at 70kph or even cresting a hill and up shifting (but only ever after about an hour or so of driving) I get a low fuel rail pressure code along with a transmission control module communication loss. I’ll write a much more in-depth post about the issue soon (pretty sure I’m up for a HPFP) but for now I’m wondering about this fuel temp reading.. I’m new to the iiD Tool but it looks wrong to me.. do I need a new temp sensor?

Has anyone replaced one?
Common issue?

I haven’t found much about it from this or other LR forums.

Cheers!

[josh.huber]

Did you get any codes, I found with my new gap I needed to change the settings for the codes to be read. Also there should be another option for fuel temp without it being that long of a title. Just fuel temp

[josh.huber]

So I went out shed again and had a look. If you go to faults then advanced. You can select which faults you wish to view. I've screen shot how both my phone ( I don't use) and tablet are set up to read my gap tool. If you click them all the read takes forever. The second photo is the tablet.

https://uploads.tapatalk-cdn.com/20200326/17cbb491466758ef54acdabae98241b3.jpghttps://uploads.tapatalk-cdn.com/20200326/3f873e7c94625483803e32666b6d090c.jpg

[josh.huber]

In regards to the fuel temp did you have a voltage reading available too? At that temp I suspect the sensor is incorrect and in default. You should have a code for that. On the 3.0L that's been sitting for about an hour I got this.
https://uploads.tapatalk-cdn.com/20200326/07b0b0eb5e9cc169ef4e4c9051244c82.jpg

[josh.huber]

Fuel temp sensor on that engine looks to be an old school two wire job. A broken wire or dead sensor, would cause it to either go full low or full high depending on how the ECU is programmed

[TopEndThom]

Thanks so much Josh.

I had another look at the iiD and it’s interesting - I found the other option for fuel temp but I don’t get a reading, just N/A.

https://uploads.tapatalk-cdn.com/20200327/e40268b851ad8b74c4d515a7e2812e30.jpg

The codes I was getting after the reduced performance episodes were P0087 and U2023-86 which may or may not be related to this fuel temp issue.

https://uploads.tapatalk-cdn.com/20200327/71fde054800331b88be719482abf83b2.jpg

I’ll try to get my hands on a new sensor. Without having done any research I’m assuming this is the sensor in the below photo:
https://uploads.tapatalk-cdn.com/20200327/003a9f82243c701346190adb56489270.jpg

[TopEndThom]

Oh and something to add - I don’t get an option in my ‘complete list’ of live values for a Fuel Temp Sensor Voltage’ read out. Maybe only the 3.0 got that?

[josh.huber]

There are differences between the 2.7 and 3.0 as far as what's displayed and how.

That connector in the photo is on the fuel pump. Ill see where the temp sensor is now for you, but it's unlikely located there. One of the fuel rails rings a bell for some reason

[josh.huber]

hey mate,
just read the fault codes list as im on my pc, the fuel temp really should be irrelevant if you have a code for pressure low, fuel temp is just a "trim" not a major issue with performance, clear it and see when it comes back, fuel rail low is scary, give the hpfp a good search on here and see what ya come back with.

The book says the temp sender is located on the LP fuel return line, derates engine at 85 degree's C.

[josh.huber]

Also, ive read more than once that the cause of failure is a sticking valve within the fuel pump, if you do get to the level of pain that you need to put a new one you could try a fuel lubricant, i use CEM CRD enhancer, others use mineral two stroke oil, im sure the big oil companies all make something, I think berrima diesel make theyre own as a last chance for toyota injectors. flash lube also make one.
it would be interesting to see if one of these products could cure that sticking valve for other players out there.

[Norway]

Has anyone experience this before? My fuel temp seems to sit around -30deg C when I read the live value with the iiD Tool. I live in Darwin where the average ambient temp is actually about +30deg C this time of year.. ??

https://uploads.tapatalk-cdn.com/20200325/9cd4d89873245e0a03481523548e42e0.jpg

I’ve been having issues with a reduced performance and gearbox fault problem on my 2009 2.7 Disco 4. After loss of power at random times, could be cruising on flat road at 100kph or downshifting on a slight rise at 70kph or even cresting a hill and up shifting (but only ever after about an hour or so of driving) I get a low fuel rail pressure code along with a transmission control module communication loss. I’ll write a much more in-depth post about the issue soon (pretty sure I’m up for a HPFP) but for now I’m wondering about this fuel temp reading.. I’m new to the iiD Tool but it looks wrong to me.. do I need a new temp sensor?

Has anyone replaced one?
Common issue?

I haven’t found much about it from this or other LR forums.

Cheers!


Hello. Did you replace the temperature sensor? And did it solve the problem?

[muddy]

question

does the telemetry (cpu ) receive signals from sensors either 0-5v or 4-20 mA (analogue) eg temp if so that would account for an open circuit .
incorrest reading

[Old Farang]

question

does the telemetry (cpu ) receive signals from sensors either 0-5v or 4-20 mA (analogue) eg temp if so that would account for an open circuit .
incorrest reading

I am not up with D4 sensors, but previous models used a thermistor type sensor. The resistance changes with the changes in the fuel rail temperature. Never seen one with either 0-5volts, or 4-20 mA.

[muddy]

Hi Fang

That is the actual voltage/current changes that is caused by the changes in the thermistor resistance (ohms) to input into the cpu

i am talking about the inputs to the cpu where those readings are the outputs from the cpu

[Norway]

Hi Fang

That is the actual voltage/current changes that is caused by the changes in the thermistor resistance (ohms) to input into the cpu

i am talking about the inputs to the cpu where those readings are the outputs from the cpu

The engine ecu (pcm) sends out a common 5v line to several sensors, the pcm reads the voltage after each sensor.

[muddy]

The engine ecu (pcm) sends out a common 5v line to several sensors, the pcm reads the voltage after each sensor.



thanks that what i thought