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blackwolf

Member Since: 03 Nov 2009
Location: South West England
Posts: 17731

2007 Defender 110 Puma 2.4 DCPU Stornoway Grey

I think that the main reason most tuners recommend taking a tuned map off is that no-one outside LR knows exactly how the recalibration algorithm actually works. Logic suggests that the ecm will manipulate the VCV and monitor various engine parameters to see the effect of the various VCV input signals. A remap may affect the performance of the engine during these tests and result in a calibration which is different to that which would be obtained with a factory map. That's the theory.

I faced exactly the same situation as Steve. My EGR hasn't 'actuated' for 7 years and undoubtedly won't work properly if I revert to a standard map. To do so to recalibrate the VCV would be pointless since I'd have to replace the EGR first, simply to get the engine running well enough to undertake the VCV recalibration. Because of this, each time I have recalibrated the VCV I have left the remap on as the lesser of two evils. All I can say is that this hasn't caused any problems at all with the recalibration, as far as I can tell.

This doesn't mean that that it is good practice, nor that it will work perfectly for everyone, but it has always worked for me.

Remember also that the ecm self-calibrates in normal operation, at intervals which increase as the mileage increases. A low mileage engine will probably self-calibrate in a fairly short time and may not need "forced" recalibration ; mine at over 200k may possibly never recalibrate itself.

There is also a suggestion that the Puma ecm may only be able to support a finite and fairly limited number of VCV and/or injector recalibrations before it runs out of internal NVRAM. I have discussed this with several people in the tuning trade and although no-one has been prepared to state categorically that it is not the case, no-one (I have spoken to, anyway) has encountered a vehicle where this has happened, even on vehicles which have had many, many recalibrations. It is quite likely therefore that this is not, in fact, a problem.

14th Feb 2017 12:45am

agentmulder

Member Since: 16 Apr 2016
Location: Outer Space
Posts: 1324

^ More than double of what I hoped to say in terms of both detail and clarity.

More on the ECU memory issue here:

http://www.defender2.net/forum/topic51730.html Solved the bowel problem, working on the consonants...

14th Feb 2017 1:19am

custom90

Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20770

Thank-you BW, highly detailed and very informative as usual.

Agentmulder - Will take a look at your link when I have time to read later.

I'd imagine the ECM memory is limited but more than enough to last over and above the vehicles lifetime.
Probably 10 calibrations or 20 or similar figure.
I'd imagine this is why they state that it should be done only with a VCV change and not simply because someone fancys fettle / self tune up. WeWillWin🇬🇧🇺🇸
⛽️🛢️⚙️🧰💪

14th Feb 2017 11:51am

blackwolf

Member Since: 03 Nov 2009
Location: South West England
Posts: 17731

Pete Bell, in another thread wrote:
... I have personally programmed my own 2.2 and many 2.4 well over 100 times with new injector codes and such without issue.

I don't think you need to worry!

14th Feb 2017 12:29pm

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