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Recently I had my 159 Jtdm with 80000 km remapped and the EGR closed. The DPF was left alone for ecological reasons.

Though there is better acceleration in first and second gear the fuel consumption has raised from 37mpg to 39 mpg. ( 7.5 to 7.8 km/L)

I have been trying to drive more economically, but the consumption on the display won't go down.
One morning it even went absurdly high to fall down after a 1 hour drive.

1. Would the non removal of the DPF make such a difference in the effect of the remap?
2. DPF's have life guarantee but can they get blocked or need cleaning?
3. Can remaps have consequences for board computer readings?

Many thanx for your opinions and advise!
 

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1. DPF is a restriction in exhaust - restrictions in exhaust of any car will affect fuel economy
On top of that DPF needs to be regenerated which means squirting even more fuel into the engine during exhaust stroke to increase temperatures
so basically, remap == more fuel+more air == more exhaust flow == more backpressure

2. DPFs get blocked with two things soot and ash, soot is burned during regeneration and comes from not perfectly burned fuel, ash is coming from oil (that's why DPF cars need low ash oils) and fuel impurities, ash will stay in the DPF forever - it is the ash that causes DPF to fail after a while regardless of the driving style, soot does not cause any problems as long as you don't allow it to build up to the point where there is so much backpressure that engine can't increase temperatures to levels high enough to burn it off.

3. depends on the remap - good remap will not have any effect on trip computer readings, bad remap will make it show a lot better usage
http://www.hdi-tuning.co.uk/downloads/what-is-altered-in-a-bad-remap-file-2LHDI-EDC15C2.pdf
This explains it very well, and it doesn't matter how much you pay for your remap - there are people that will charge you £700 for remap of that quality.

Because of the fact that bad remap like that will cause car to smoke more, the DPF will get cloged faster and need to be regenerated more often, also smoke == wasted fuel.
 

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Thanx for this usefull information, J!
That explains a lot.

Knowing I prefer not to drive around with a smoking diesel, what do you recommend?
 

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however so called good companies that charge a lot for remaps still end up with the fuel computer fooled

in the end we all need to back to petrol cars and batteries, for now im just enjoying the huge torque of my 2.4
 

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however so called good companies that charge a lot for remaps still end up with the fuel computer fooled

in the end we all need to back to petrol cars and batteries, for now im just enjoying the huge torque of my 2.4
That's because they don't do good quality remaps - unless you read the map from the car and see what has been changed you don't know that all engine protection maps have been changed in a way that is potentially dangerous (in case of faults it will still deliver full power rather than going into limp mode), DTCs have been removed (you need to remove some DPF related ones, but they are "hard" to find, it's a lot easier to remove whole block of them, so your low oil pressure warning is gone, turbo under/over pressure warning is gone as well and few others) and injector calibration map is wildly incorrect - what you will see as a user is that you've got more power/torque and no warning lights, you will also notice better MPG readings on the trip computer.
 

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yes autolusso penrith spent several hours downloading the ecu in my car only to find it was already modified, but they couldn't tell who by and injection pressures were very high in the maps in my car. Possibly a red dot map

I sorted of wish now id asked them to put it back to a standard map and then modify it to one of there maps.

I had an alfatune map on a previous car, trip computer mpg went up 15mpg ! went like stink though
 

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yes autolusso penrith spent several hours downloading the ecu in my car only to find it was already modified, but they couldn't tell who by and injection pressures were very high in the maps in my car. Possibly a red dot map

I sorted of wish now id asked them to put it back to a standard map and then modify it to one of there maps.

I had an alfatune map on a previous car, trip computer mpg went up 15mpg ! went like stink though
We can put it back to standard for you, we would only need the ECU not the whole car

That said, standard with EGR delete or however you want it

Ned
 
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