Starting problems 2003TD5 Defender

[whynot]

G'day all, any anyone that can help.
I have a 2003 TD5 Defender that is inconsistend with it's starting. The problems occures out of the blue, Hot or Cold, however the thermostat always goes to the RED.... The motor turns over as normal, just no start.
I have a digital temp / oil alarm installed and the temp is never hot

Some of the things I have tried to get it going, but not real reason for the starting afterwards are: -
1)Starting in Gear - first and second - hopefully to free up compression etc etc
2) Drop some fuel out of the fuel line at the filter
3) check fuses - give them all a tap
4) Knock on the computer
5) turn ignition on and off numerous times...

The minister of Domestic affairs and Finance went to drive out this morning after sucessfully starting, when it shut down ( no she did not stall it) I went to check and sure enough the it did tha same as above.... I turned the ignition on and off and after about the second attempt it fired up...

Any suggestions - unfortunatelly the mechanics cannot do anything withn it until it gets more serious, or it plays up and I drive it straight there without turning off the motor - so thay can read the computer..

Anybody had similar instances or advise... it's getting to the stage where it restricts where we go...

Cheers
Andrew

[OffTrack]

I'd be looking for a new mechanic for a start.

The fact that the temp gauge is going into the red a start up is a pretty good indicator of what is amiss.

I don't have the Defender workshop manual, but assuming the Engine Coolant Temp sensor is wired the same as the Disco2 it is hooked directly to the TD5 ECU. I'm also assuming that your digital gauge has it's own temp sensor, so what you're reading on the digital gauge doesn't reflect the information the ECU is seeing.

On the above assumptions I'd suggest either your factory temp sensor is faulty, or the wiring from the sensor to the ECU has a short circuit. I'd check the sensor first.

D2 uses a different sensor to the Defender, so I'm not sure what correct resistance figures are.

If the sensor measures ok, check the wiring back to the ECU for worn insulation.


The ECT sensor can fail the following ways or supply incorrect signal:

Sensor open circuit.
Short circuit to vehicle supply.
Short circuit to earth.
Incorrect mechanical fitting.
Signal fixed above 40 °C (104 °F) not detected.
Signal fixed below 40 °C (104 °F) not detected.

In the event of an ECT sensor signal failure any of the following symptoms may be observed:

Difficult cold start.
Difficult hot start.
Driveability concerns.
Instrument pack temperature warning illuminated.
Temperature gauge reads excessively hot.
Temperature gauge reads excessively cold.

In the event of component failure the ECM calculates coolant temperature from the fuel temperature sensor signal. If
this occurs, the limit engine operation if coolant temperature is too high becomes inoperative.
The MIL will not illuminate in an ECT sensor failure.

hope this helps

Paul

[mturri]

Agree with Paul's diagnosis and would replace the ECT sensor as it is a very easy & inexpensive thing to do. Also check the loom adjacent to the sensor as it tends to get toasted against the block.

May I correct Paul though in saying that the temperature sensor (LR p/n ERR2081) is the same across all Td5 engines (with the exception of some very early ones). In fact it is the same temperature sensor that is used across the engine block in the fuel pressure regulator.

It is also widely used in the auto industry and the OEM piece is Bosch p/n 0280130026.

The sensor is essentially a temperature dependent variable resistance, between 10 and 30 C it should measure between 3.8 and 1.7 K ohms which gives a feel of what resistance you should obtain at ambient temperature; if the sensor shorts (either internally or externally at the connector/loom) the ECU interprets this as coolant temperature shooting through the roof and restricts fueling which may very well be the cause behind your troubles.

https://www.aulro.com/afvb/images/imported/2012/02/603.jpg

Rgds
Matt

[OffTrack]

May I correct Paul though in saying that the temperature sensor (LR p/n ERR2081) is the same across all Td5 engines (with the exception of some very early ones). In fact it is the same temperature sensor that is used across the engine block in the fuel pressure regulator.

Thanks for the correction, Matt. I made the fundamental mistake of assuming information posted to Landy Zone might actually be correct without verifying first. Checking Microcat, you are 100% correct re: the parts numbers.

I think that you might have missed a K in the resistance figures. The range is 3792 ohm/3.8K ohm (at 10ºC) to 1707 ohm/1.7K ohm (at 30ºC).

cheers
Paul

[mturri]

I think that you might have missed a K in the resistance figures. The range is 3792 ohm/3.8K ohm (at 10ºC) to 1707 ohm/1.7K ohm (at 30ºC).

Thank you for spotting that! Intended but did not throw the Ks in... changed now for the sake of rightness.

[Blknight.aus]

also check the earths on the ECU under the drivers seat That gives similar wierd faults

[TOUTERRAIN]

Hi, I had almost the same fault, Temp gauge doing wierd things, not starting, and as the last post says it was a bad earth, but not under the ecu, it was the seatbox its self, I know its held in by 25 bolts, but not one had a good earth, I just tightened one on battery side, and it started streight away and has been faultless for 3 months, It depends on how hard you jump into seat to if it earths or not, strange but true
Anthony

[crivelli]

Hi, Do you have controlled main relè?

[whynot]

Thanx for the interest and feedback..... finally got a resolve.

It was a $12.50 Relay for the ECU.... which I susspected...

cheers.
Andrew