Lorryman100 wrote:

A couple of my thoughts/ramblings on possible causes on the electrical side of this problem?

The ECU protocol for high coolant temp is for the fan to run continuously whether the coolant is hot or cold. The sensor used by the ECU to monitor coolant temp is the CHT sensor (cylinder head temp) which is located at the rear of the engine at the coolant manifold junction. The ECU uses this sensor to do fueling calculations, limit engine operation if engine coolant temperature becomes too high, cooling fan operation and glow plug activation time. If this sensor is faulty the ECU defaults to a stored temp of 80C and runs the cooling fan continuously which can lead to: difficult cold start, difficult hot start, engine performance compromised and temperature gauge inoperative or inaccurate reading.

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HTH Brian

Hi Brian, all correct but not about fan to run continuously.

The defender have the fan viscous coupling without any electrical connection with the ECU.

Some times if the viscous coupling is faulty you can see the water temp going up...... Discovery 5 td6 HSE Stornoway Gray Outback Engineering Limited Edition

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The Boy wrote:

Is Brian talking about he aircon fan? I (rightly or wrongly) thought that in the event of the engine overheating this would cut in and run.


I might invest in a temperature monitor from Haydn Alarms so at least I have an idea of what’s going on and at 93 quid it’s not going to break the banks.

The condenser fan is the only electrical operated cooling fan on the Puma and is controlled by the ECU ( Relay Cooling fan R117), my fault for not stating that as I assumed everyone knew about the viscous fan?

Boy, you may be better off in purchasing a scangauge for a little more money, as it does have the ability to monitor a lot more sensors. IMHO Have a read of their site for info before you make your choice

Brian.

CRJ wrote:

Hi
Just a short question about the actuator arm - should I be able to move it up and down - or just see that it moves freely in the joints? Mine moves in the joints - but I can´t move it up or down at all
Regards
CRJ

Christian, you will get some movement on the vane control arm and at both ends of the control bar though the modulator arm should not move.Check that the control bar is not seized or has too much play where it attaches to the modulator or to the vane control arm. How much play do you have at each end where it attaches to the modulator/vane control arm?

Turbo Modulator Harness:


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Turbo Modulator Harness Plug:


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Modulator control bar:


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You can see the modulator arm at the top of the control bar and the vane arm at the bottom.

Brian.

Lorryman100 wrote:

DG we are not talking about what the ECU employs in its strategy as I listed previously, but what tell tale there is for a failed/failing CHT sensor, harness/plug. The workshop manual also states that the electric fan will operate continuously when the CHT fails and that the ECU controls this as part of its overheating strategy. The reason the fan runs continually is because the ECU is using the stored value of 80C and does not know what the real temp is, and so as a safety runs the fan continually to assist with coolant cooling whether the coolant is cold or warm.
Fair point about non air con defenders but I have an XS, and that is what I tinker about with and submit posts about.

 Discovery 5 td6 HSE Stornoway Gray Outback Engineering Limited Edition

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MD5 wrote:

Which is the best way to clean the MAF sensor ? I read somewhere that it must not be touched in any way but only cleaned with a contact cleaner spray. Is this real ?

And where is located the turbo actuator arm ? A pics will be greatly appreciated!

Pics above

I would just replace the MAF sensor if I had any doubts about it working as it should, as they are not serviceable and do not cost that much, about £35 IIRC.

MAF sensor location:


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Failed MAF sensor:


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MAP sensor location:


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Brian.

dgardel wrote:

Lorryman100 wrote:

DG we are not talking about what the ECU employs in its strategy as I listed previously, but what tell tale there is for a failed/failing CHT sensor, harness/plug. The workshop manual also states that the electric fan will operate continuously when the CHT fails and that the ECU controls this as part of its overheating strategy. The reason the fan runs continually is because the ECU is using the stored value of 80C and does not know what the real temp is, and so as a safety runs the fan continually to assist with coolant cooling whether the coolant is cold or warm.
Fair point about non air con defenders but I have an XS, and that is what I tinker about with and submit posts about.

wslr wrote:

Not wanting to worry anyone with a hypotheses, but have you thought that adding 2 stroke oil or using poor fuel may actually contribute to this. Just an hypotheses, so no shouting please.

The theory is that the 2SO actually burns up completely in the burn and actively reduces the ash/carbon build up? I do agree with the poor fuel hypothesis, as a low cetane rated fuel has been proven to increase carbon build up by taking longer to ignite and burning quicker resulting in higher emissions and a rougher running, sounding engine.