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Maxxed_Ross



Member Since: 06 Jun 2012
Location: Bathgate / North Sea
Posts: 340

Scotland 2001 Defender 90 Td5 CSW Cobar Blue
TD5 cutting power at high revs
I'm at the end of my tether with this one, so hopefully someone can help. I've been through every "power" related thread and still can't find an answer

So the story goes:

Bought a 2001 TD5 90 just over a year ago. Was remapped by a company I've never heard of but pulls like a train. Fuel economy and torque delivery was decent so I fitted a Disco 2.1 transfer box and slightly bigger tyres. It's also running a bigger alloy intercooler.

Ran fine for a while then occasionally would loose power on the motorway. I changed the fuel filter and this seemed to solve it for a while. Since then it has been progressively getting worse to the point where it's almost impossible to drive.

The issue happens in all gears if they're held for too long, so I've gotten into the habbit of short shifting and just sitting at 60 on the motorway. All is fine until I either let the revs wander up a bit too high or I hit a hill. The engine starts the clatter, they're a huge ploom of black smoke out the back and all power is lost. I've tried keeping my foot planted but it just gets slower and slower. lifting off and accelerating again brings back normal power until it happens again.

Strange thing is that once it happens that first time it'll do it totally at random while driving. The slightest load increase by going up a hill, an increase in head wind or even over taking a lorry can trigger the power cut again. If the car is turned off fully then started again it'll cruise past trucks at 60mph without any issues at all

I've had a nanocom plugged in during a test run and the turbo pressure drops totally when this happens

Injector balance is good, MAF readings are normal and the only weird fault code it threw up once was an overspeed crank detection... but it's never shown that before or since.

The list of things I've checked / changed / swapped

- EGR fully removed and blanked, all blanks and plugs ok
- New genuine MAF 6 months ago
- New genuine crank sensor with spacer
- New genuine fuel pump
- New mahle fuel filter, no change at all this time
- Recent diesel pressure regulator with genuine gasket
- Regularly checked Terrafirma air filter
- New silicone boost hoses
- Turbo play checked and ok
- Turbo hoses all checked and ok
- Swapped actuator, no success
- Wastegate moves fine
- Actuator rod set for 13 threads (standard I believe)
- MAP sensor swapped with another working vehicle, no change
- Injector washers and loom replaced about 6 months before issues
- Minimal oil in the ECU harness
- Fitted Alive boost box, no change

I also tried swapping the ECU for a standard one. Obviously this made it really sluggish to drive but it didn't fix the issue - although it did change it slightly. Whereas the mapped ECU required a full lift off from the throttle to recover power the standard ECU would boost fine then cut, then boost fine again then cut with the foot held firmly to the floor.

The only thing that gave me slight hope was cleaning the crank sensor. Last time I found a little bit of swarf on the end and cleaning that made it rev up perfectly for about a mile - then it started to play up again.

I'm properly at a loss now. Next step is to change the dual mass flywheel (clutch needs done anyway) so I'm hoping to find something in there.

Any ideas?
Post #702992 25th Apr 2018 4:47am
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bankz5152



Member Since: 02 Feb 2017
Location: South London/North Kent
Posts: 2158

2004 Defender 110 Td5 DCPU Epsom Green
Unplug the MAF and go for a drive.
Post #702999 25th Apr 2018 5:32am
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roel



Member Since: 08 Aug 2009
Location: Lelystad
Posts: 2039

Netherlands 2003 Defender 90 Td5 PU Caledonian Blue
How high does your turbo pressure go before it cuts out? Roel

1984 90 2.5 na Diesel - RR V8 (1994-2001)
1997 Camel Trophy Discovery 300TDI (2001-2009)
2005 G4 Discovery III 4.4 V8 (2008-2018) It's gone but it still hurts.
2003 90 Td5 (2009-now)
Post #703009 25th Apr 2018 7:36am
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Maxxed_Ross



Member Since: 06 Jun 2012
Location: Bathgate / North Sea
Posts: 340

Scotland 2001 Defender 90 Td5 CSW Cobar Blue
Unplugged the MAF and it's still the same

Boost pressure looks to be normal I think, them drops totally
Post #703088 25th Apr 2018 3:03pm
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dorsetsmith



Member Since: 30 Oct 2011
Location: South West
Posts: 4554

fuel presser Question
Post #703091 25th Apr 2018 3:25pm
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gazman



Member Since: 17 Aug 2015
Location: Liverpool
Posts: 652

United Kingdom 2003 Defender 90 Td5 HT Alpine White
It does sound like a over boost issue, but mine did similar when the fpr died. I mad3 a gauge up to fit where the temp sensor is on the fpr. I think it's m12.

I ended up renewing loads of the fuel system. I also did a flywheel change which made it a bit better as it was on its way out too 2014 - current ..... 2003 defender td5 90 (my car)
2009 - current .... 2005 zx10r
Post #703099 25th Apr 2018 4:00pm
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NickMc



Member Since: 01 Oct 2014
Location: Norn Iron
Posts: 1624

Northern Ireland 2006 Defender 90 Td5 HT Bonatti Grey
I’d be ditching the remap and starting from there. Or getting someone with proper Diagnostics experience before throwing more good money after bad. There’s some terrible remaps out there installed by people that don’t have a clue. It sounds like a fueling glitch with the surge and black smoke. If anyone can diagnose a driveability problem without seeing it or driving it ask them where they got their crystal ball from and can I have the details? Whistle
Post #703103 25th Apr 2018 4:11pm
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Laurie



Member Since: 22 Feb 2008
Location: Sussex, England
Posts: 2897

England 2005 Defender 90 Td5 XS CSW Bonatti Grey
Check the temp gauge when it drops power.
Could be momentarily overheating and switching to limp mode.
The temp gauge goes from normal to max with nothing inbetween so it's easy to spot. 
Post #703105 25th Apr 2018 4:25pm
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roel



Member Since: 08 Aug 2009
Location: Lelystad
Posts: 2039

Netherlands 2003 Defender 90 Td5 PU Caledonian Blue
I still think boost pressure I believe that 1,3 bar is when the ecu says it is enough and goes in limp mode. Mine peaks at 1,28 bar and no problems. So an exact number would be nice.
This might be a result off the remap but you mentione it does the same with a standard ECU so that should rule the remap out.

Is your red ecu plug oil free? You mentione a little oil. What is a little and does it make a diffrence if you clean the plug?
I would say also check in the ecu but you also tested another ecu so that should be ok. Roel

1984 90 2.5 na Diesel - RR V8 (1994-2001)
1997 Camel Trophy Discovery 300TDI (2001-2009)
2005 G4 Discovery III 4.4 V8 (2008-2018) It's gone but it still hurts.
2003 90 Td5 (2009-now)
Post #703106 25th Apr 2018 4:25pm
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NickMc



Member Since: 01 Oct 2014
Location: Norn Iron
Posts: 1624

Northern Ireland 2006 Defender 90 Td5 HT Bonatti Grey
Throwing more parts at it is just increasing the variables.

What ECU are you running?

When you put a standard ECU in what number is it? What files are on it? Did you remove the boost box when you did?
Post #703107 25th Apr 2018 4:33pm
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gazman



Member Since: 17 Aug 2015
Location: Liverpool
Posts: 652

United Kingdom 2003 Defender 90 Td5 HT Alpine White
Laurie wrote:
Check the temp gauge when it drops power.
Could be momentarily overheating and switching to limp mode.
The temp gauge goes from normal to max with nothing inbetween so it's easy to spot.


My main relay was on its way out and caused that too. But the water gauge would jump quickly before settl8jg down again 2014 - current ..... 2003 defender td5 90 (my car)
2009 - current .... 2005 zx10r
Post #703109 25th Apr 2018 4:37pm
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Maxxed_Ross



Member Since: 06 Jun 2012
Location: Bathgate / North Sea
Posts: 340

Scotland 2001 Defender 90 Td5 CSW Cobar Blue
Thanks for all the replies everyone

dorsetsmith wrote:
fuel presser Question


It's had a new pressure regulator (was leaking anyway) not long after I bought it, new fuel filter and new genuine fuel pump (was getting a bit noisy) with no change - so I don't think it's fuel related

NickMc wrote:
I’d be ditching the remap and starting from there.


It drove fine when I first purchased so I don't think it is the map, but to rule it out I did fit a Disco ECU that a friend sent me to try. didn't solve the problem as in the top post. All the standard ECU did was make it much slower Laughing

Laurie wrote:
Check the temp gauge when it drops power.
Could be momentarily overheating and switching to limp mode.
The temp gauge goes from normal to max with nothing inbetween so it's easy to spot.


Nope the Temp Gauge stays just below half as normal Sad

roel wrote:
I still think boost pressure I believe that 1,3 bar is when the ecu says it is enough and goes in limp mode. Mine peaks at 1,28 bar and no problems. So an exact number would be nice.
This might be a result off the remap but you mentione it does the same with a standard ECU so that should rule the remap out.

Is your red ecu plug oil free? You mentione a little oil. What is a little and does it make a diffrence if you clean the plug?
I would say also check in the ecu but you also tested another ecu so that should be ok.


It was around that figure - but I fitted the boost box to try and rule that out. It didn't make any difference at all. As it has been a gradual deterioration I suspect that something is failing somewhere.

The red ECU plug has a tiny bit of residual oil from before the loom change. I clean it regularly hoping that it will eventually stop seeping down... and there's nothing inside the ECU itself. It's not a random miss-fire like I would expect from an oily plug either

NickMc wrote:
Throwing more parts at it is just increasing the variables.

What ECU are you running?

When you put a standard ECU in what number is it? What files are on it? Did you remove the boost box when you did?


Most of the sensors have been swapped from vehicles that are running fine and then swapped back if there's no change. Sorry should have made that clearer. Only the MAF (was faulty about 6 months ago) and crank sensor (had a chunk out of it because of no spacer) have actually been swapped out totally... but I did try others from working vehicles to rule them both out with no change at all.

As for the ECU it's just the original one, so not too sure what you mean? When I fitted the Discovery ECU to test I just coded it to the vehicle using Nanocom and it started first time no bother. It will drive fine (granted much slower due to the lack of remap combined with my higher overall gearing) and the issue happens at exactly the same point in the revs. I didn't take the boost box off when trying the standard ECU
Post #703140 25th Apr 2018 6:57pm
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NickMc



Member Since: 01 Oct 2014
Location: Norn Iron
Posts: 1624

Northern Ireland 2006 Defender 90 Td5 HT Bonatti Grey
Am you get a video of the fault or a screen shot of the live data?

Does the ECU you have start with the part no MSB.... or NNN?

Discovery and Defender ECUs are different and will work, but not be correct.

What brand of crank sensor and MAF did you use some aftermarket are junk from the box.

You say it worked better with the non mapped ECU but the boost seemed funny could that be your boost box causing that?

Different ECUs and vehicles have different fuel map files.

I mean this in the nicest possible way, but I think you should stop torturing yourself and take it to someone with a bit more experience with the diagnostic scanner Confused

The chunk out the the crank sensor is strange the spacer mod was for intermittent signal faults not taking out chunks.

Have you tested the DMF?

You say about a crankshaft sensor improving it they could scope the signal on the sensor.
Post #703152 25th Apr 2018 7:19pm
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Maxxed_Ross



Member Since: 06 Jun 2012
Location: Bathgate / North Sea
Posts: 340

Scotland 2001 Defender 90 Td5 CSW Cobar Blue
NickMc wrote:
Am you get a video of the fault or a screen shot of the live data?


I can try

NickMc wrote:
Does the ECU you have start with the part no MSB.... or NNN?

Discovery and Defender ECUs are different and will work, but not be correct.


The ecu is bolted back under the bucket seats again, so I'll get that when I next have a chance to remove them

NickMc wrote:
What brand of crank sensor and MAF did you use some aftermarket are junk from the box.


Both are genuine items

NickMc wrote:
You say it worked better with the non mapped ECU but the boost seemed funny could that be your boost box causing that?

Different ECUs and vehicles have different fuel map files.


I wouldn't say it was better, more that the issue became self modulating instead of me having to release the throttle. Happens at exactly the same point in the rev range with both ECUs just with slightly different results. I'' try the standard ECU again without the boost box when the seats are next out

NickMc wrote:
I mean this in the nicest possible way, but I think you should stop torturing yourself and take it to someone with a bit more experience with the diagnostic scanner Confused


No offence taken, I borrowed the Nanocom to code the standard ECU and was talked through how to check the MAF and injector readings by someone who knows what they should be - both were fine. Apparently the MAF was reading a bit high but that was put down to the Terrafirma air filter letting more air in at idle

NickMc wrote:
You say about a crankshaft sensor improving it they could scope the signal on the sensor.


When I cleaned the swarf from the end is improved things briefly - but I've tried 3 other crank sensors (two genuine one aftermarket) and they all produced the same results instantly[/quote]
Post #703154 25th Apr 2018 7:30pm
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bankz5152



Member Since: 02 Feb 2017
Location: South London/North Kent
Posts: 2158

2004 Defender 110 Td5 DCPU Epsom Green
You need diagnostics.
Post #703161 25th Apr 2018 7:48pm
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