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BaronDefenders



Member Since: 28 Jun 2019
Location: London/Cotswolds
Posts: 896

United Kingdom 2004 Defender 90 Td5 CSW Santorini Black
Responsiveness
This is something I’ve noticed for an age, but I’m finally curious enough to address it now.

When driving my Td5 it’s absolutely fine. However, when I stop for fuel or a break and then start off again, I notice the Td5 is very much more responsive for a short while. Boost and power will start much lower in the rev-range and the delivery is smoother. It then returns to its norm after an unknown period of time.

I’m guessing some sensor resets upon shutdown and restart and is faulty.

Any thoughts?

Likely the MAF? Charlie

1949 Series 1 80 (SOLD)
2002 Td5 90 (SOLD)
2008 Freelander 2 (SOLD)

1958 Series 2 88 Pastel Green (2019 LR Legends Best Restored)
1983 V8 110 Limestone (Previously owned by Tom Sheppard MBE)
2004 Td5 90 Santorini Black (Td5INSIDE Powered & Rebuilt by CSK)
2012 Puma 110 Zermatt Silver (Overlanding Build)

Instagram: @BaronDefenders
Post #1038806 30th Jun 2024 7:52pm
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Zimblewinder



Member Since: 12 Jan 2019
Location: Geelong
Posts: 43

Australia 2000 Defender 130 2.5 TD HCPU Chawton White
turbo bearings? How long until the power comes off?
Post #1038824 30th Jun 2024 11:40pm
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BaronDefenders



Member Since: 28 Jun 2019
Location: London/Cotswolds
Posts: 896

United Kingdom 2004 Defender 90 Td5 CSW Santorini Black
I doubt it, it’s running a CR Turbos VNT.

The power is still there, just the delivery changes. So it’ll come later in the rev-range. I have no idea how long it takes for things to return to”normal” as I usually only notice this when I’m driving on a motorway. I’ll stop and then get back on to the motorway and cruise for quite some time. It could become less responsive after 5 minutes or 30, I have no idea! Charlie

1949 Series 1 80 (SOLD)
2002 Td5 90 (SOLD)
2008 Freelander 2 (SOLD)

1958 Series 2 88 Pastel Green (2019 LR Legends Best Restored)
1983 V8 110 Limestone (Previously owned by Tom Sheppard MBE)
2004 Td5 90 Santorini Black (Td5INSIDE Powered & Rebuilt by CSK)
2012 Puma 110 Zermatt Silver (Overlanding Build)

Instagram: @BaronDefenders
Post #1038836 1st Jul 2024 6:59am
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TexasRover



Member Since: 24 Nov 2022
Location: Paris
Posts: 1051

France 2002 Defender 110 Td5 DCPU Chawton White
Unlike with Petrol where the amount of fuel and air need to be exactly mixed, with Diesel you can have power issues because the system is not injecting enough fuel (or air). The MAF (Manifold air flow) is known to 'loose calibration', although some say it is only used for the EGR (exhaust gas re-circulation).

The other thing to suspect is the electric fuel pump in the tank. When it fails the engine will still pull in fuel (unless air is introduced) but without head pressure the injectors might not make full flow. Did you check the fuel pump? You can remove a fuel line at the fuel cooler and check for a healthy flow, but if your pump is fuber you will introduce air and not be able to start the engine until you install a new pump, so you need to be ready for that.

Other thing could be the MAP (manifold air pressure) sensor in the intake manifold. This will be used to avoid overfuelling, but could read wrong reducing fuel delivery. Also you can have an air leak from the turbo end so you don't get the charge pressure and the associated reduce fuel delivery

There is also a engine temp sensor used for fueling..

All these things should be checked with a reader like Nanocom against documented numbers before unloading the parts cannon.

I find that TD5s run quite happily with something wrong and won't throw any engine lights, or codes but to get the engine to work as it should you need to make sure everything is working properly through a systematic diagnostic approach.
Post #1038847 1st Jul 2024 9:52am
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BaronDefenders



Member Since: 28 Jun 2019
Location: London/Cotswolds
Posts: 896

United Kingdom 2004 Defender 90 Td5 CSW Santorini Black
The fuel pump is working fine. Makes the usual whine when moving the ignition to position II and it will run a purge without issue. The vehicle will pull and make power all through the rev-range, so there’s no fuel starvation at higher RPM.

There aren’t any boost leaks. I have a boost gauge and can get up to a peak of 1.7bar when really making a hard pull in 4th gear.

I will plug the Nanocom in on Friday and check the readings. I suspect it will be the MAF or MAP. I have, now that I think about it, noticed reduced performance when at altitude (1,000m+). Charlie

1949 Series 1 80 (SOLD)
2002 Td5 90 (SOLD)
2008 Freelander 2 (SOLD)

1958 Series 2 88 Pastel Green (2019 LR Legends Best Restored)
1983 V8 110 Limestone (Previously owned by Tom Sheppard MBE)
2004 Td5 90 Santorini Black (Td5INSIDE Powered & Rebuilt by CSK)
2012 Puma 110 Zermatt Silver (Overlanding Build)

Instagram: @BaronDefenders
Post #1038852 1st Jul 2024 10:16am
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