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andrewfaber



Member Since: 14 Jun 2016
Location: South Africa
Posts: 7

Intermittent power loss
Any help please!

My puma 2.4 2009 model recently started momentarily loosing power or surging, particularly on long up hill climbs at around 100km/hr. I have established that it is not the fuel pump (if it was then it would do it all the time and I would have not done about 5000kms with this surging). I have had the ECU scanned for faults on many occasions and it normally comes up with no errors. However it has once had an error saying there is a short in the ECU and when it was cleared it came back straight away, it has since gone away and there has never been any engine or warning lights on the dash. Sometimes the vehicle goes 20kms before surging again. I am at the conclusion that there is a problem with the ECU and am trying to get it replaced with a second hand ECU. Has anyone else had a similar problem or have any ideas about the cause of it?
Thanks
Post #540117 14th Jun 2016 4:43pm
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Eduardo



Member Since: 28 Aug 2008
Location: RegiĆ³n Metropolitana
Posts: 2108

Chile 2007 Defender 110 Puma 2.4 SW Stornoway Grey
andrewfaber

Probably it is the engine safety management system that cuts the power when the coolant temperature goes over ~120°C...

This issue happens specially in hot days when the car is under pressure (i.e. climbs in 5t or 6th gear at high speed) Some of us have this problem for a looooooong time. The heating is quite fast and most of the times are not reflected in the temp dial in the car, but can be checked with any ODBII reader.

In my case I change the intercooler and the thermostat for other that opens at low temperature and use the spacer nut for the fan provided by Nakatenga. During last summer all going well but still not sure if the problem is solved.

A lot of information is available in the site regarding possible causes and solutions.
I'm tend to think in a degradation of the radiator but its a major cost that I dont like to assume yet.

Cheers! Eduardo

MY 2007 110 SW PUMA 2.4: Big Fog of 64'
MY 1994 Jayco 1207 Folding camper: "El Tremendo"

Click image to enlarge
Post #540277 14th Jun 2016 11:59pm
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andrewfaber



Member Since: 14 Jun 2016
Location: South Africa
Posts: 7

Thanks, that makes sense and it is a possibility. I have been advised to clean the MAF sensor ando check the turbo hoses as they may be collapsing under load.
Post #540288 15th Jun 2016 6:36am
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andrewfaber



Member Since: 14 Jun 2016
Location: South Africa
Posts: 7

The power loss is very intermittent, and very short, it lasts about 1 second and then power returns, this will occur several times going up a hill.
Post #540289 15th Jun 2016 6:39am
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Eduardo



Member Since: 28 Aug 2008
Location: RegiĆ³n Metropolitana
Posts: 2108

Chile 2007 Defender 110 Puma 2.4 SW Stornoway Grey
MAF is another possibility (also I had that Sad ), but in general the power loss failure happens randomly independant of the driving conditions.

On the other hand the safety management last more than 1-2 seconds, probably last 5-20 seconds (time neccesary to drop the temperature to an acceptable limit and have a response again).

Before change the ECU it's better to check first the wire loom that going to the ECU to see if some cable is damage and try to get some live data of the failure through an ODBII and obviously the connection of the sensors.


Regards Eduardo

MY 2007 110 SW PUMA 2.4: Big Fog of 64'
MY 1994 Jayco 1207 Folding camper: "El Tremendo"

Click image to enlarge
Post #540922 16th Jun 2016 10:03pm
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HardCharger



Member Since: 03 Mar 2013
Location: Manila, SFO, Amsterdam
Posts: 669

2011 Defender 110 Puma 2.4 SW Stornoway Grey
Given the history with the ECU, it could be possible that that is where you problem lies. Is your fuel filter due for a change? It can also lead to surging at high speeds due to high demand but limited supply from the filter. The problem will not really manifest at lower speeds unless your filter is really blocked. Worth a thought before you buy another ECU?
Post #540941 17th Jun 2016 12:56am
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nickhodgson



Member Since: 08 Dec 2009
Location: Zambia
Posts: 172

When the engine is idling "test" all the electrical connections to sensors that you can see by wobbling them. See if any of them make a difference. I found the source of a similar problem on my Puma that way - the loom was pulling on the connector and I rearranged the loom and it was repaired. Also check the relays under the seat.

The fact that the loss of power happens in relation to a certain load/speed condition may point to the engine getting hot. I would get a scan gauge or similar and view live data as you are driving.



Click image to enlarge


by the way this image is from my V8 and I am wondering about the very high intake temperature? If anyone know if 62 degrees in traffic is possible in an ambient of 25 degrees? 1995 300tdi Defender 90 P/UP
2011 Puma Defender 130 D/C
2000 300tdi Defender 110 P/UP
2015 Discovery 4 SDV6 HSE
Post #541057 17th Jun 2016 1:01pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 16812

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
It is possible that it is a defective throttle position sensor, given that on hills you may well be pressing the pedal further than you do normally.
Post #541072 17th Jun 2016 2:37pm
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andrewfaber



Member Since: 14 Jun 2016
Location: South Africa
Posts: 7

I replaced the MAF sensor today with no result, still intermittently loosing power especially toward the top of a hill. I also opened up the wiring loom that runs over the AC unit to the turbo and MAF, all the wires are in good condition and the loom is not pulling on any of the connections. I have recently changed the fuel filter (after it starting doing this) with no effect. All other filters were changed at the same time. I am starting to think it may be the VCV, however I have also seen another forum where the fuel filter housing needed to replaced as not enough fuel was getting through when under load resulting it fuel starvation.

It could be the throttle position sensor however I have tried driving up a hill keeping my foot absolutely still and towards the top of the hill it started loosing power for about 1 second and then coming back.

I have an OBDII that use to watch engine parameters when driving, when this power loss happens, the fuel rail pressure drops right down and the engine load goes to 100% and then everything returns to normal and then it will happen again. I have also used it to watch the mass air flow, the air flow will drop down when the power loss occurs and then come back as the power returns.

I have had my turbo hoses out and checked them for holes, they are both fine.
Post #541087 17th Jun 2016 4:40pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 16812

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
If you're seeing the fuel rail pressure drop, then I suspect VCV, the fuel rail PRV (less likely since when it fails it stays failed), or something causing fuel starvation (water in tank, diesel bug, crud, blocked fuel filter, etc).

The fuel system is poorly monitored on the Puma Defender, and generally it is the absence of DTCs that points to fuel. I would replace the filter, check that the fuel looks clean, and replace the VCV if changing the filter makes no difference. If the fuel is contaminated you'll almost certainly need to replace the VCV anyway, it is very susceptible to damage from contaminated fuel.
Post #541097 17th Jun 2016 5:50pm
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andrewfaber



Member Since: 14 Jun 2016
Location: South Africa
Posts: 7

I agree with you. Before it started happening I filled up in remote part of Namibia (possibly bad fuel), and everything points to a fuel problem, however changing the filter has had no effect and I have drained the filter several times to check for water and its been fine each time. My plan is to change the VCV as it only seems to happen towards the top of a hill when the load has been high for a longer period and the fuel is not being let through by the vcv fast enough, the power loss continues after the hill for a bit and then goes away
Post #541098 17th Jun 2016 5:55pm
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andrewfaber



Member Since: 14 Jun 2016
Location: South Africa
Posts: 7

Changing the VCV has had no effect on the problem, and the pressure relief valve has not popped. I don't really know where to go from here. The only other fault it has thrown out is P0110-15, faulty air intake temperature sensor, but I've just changed the MAF sensor so the temperature sensor is also new. I've just been for a drive, ambient air temperature about 13 degrees C, and the air intake temperature sensor was showing 19 degrees C consistently, and when I stopped and turned off the engine is rose to about 34 degrees C. Does this seem normal? I am suspecting that the wires going to to the ECU from the air temperature sensor are faulty, and this causing the ecu to incorrectly adjust the air fuel ratio, does this make sense to anyone?

When the surging happens, the fuel rail pressure drops, the mass air flow drops and the manifold air pressure also drops and tje engine load goes to 100% then all 3 return to normal and the engine load returns to whete it was after about 1 second.

Otherwise I may have to start looking at the fuel supply system.
Post #542117 21st Jun 2016 5:34pm
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BigRuss



Member Since: 15 May 2010
Location: Norfolk
Posts: 2785

United Kingdom 2010 Defender 110 Puma 2.4 USW Santorini Black
Is it the original turbo?

I had a similar issue where it would loose power while driving, it turned it to be a failure with the turbo control module. And as they don't sell them separately I had to have a new turbo and control module fitted. Russell
2011MY 110 XS USW Black
Post #542119 21st Jun 2016 5:43pm
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andrewfaber



Member Since: 14 Jun 2016
Location: South Africa
Posts: 7

Hi Russel

It is the original turbo, but I don't suspect the turbo, as when the road is not too steep, it can get to 140km/hr without loosing power or hesitation. But food for thought.

Andrew
Post #542121 21st Jun 2016 5:47pm
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