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Discussion Starter #1
Hi, I have an ongoing problem with my laguna 2 2003 sport tourer 1.9dci.

I have changed from a 2002 1.9dci hatchback. they both have 120bhp versions of the engines (so the V5 documents state) however there is a considerable difference in power between the two cars.

The estate is much slower than the hatchback, I have been trying to fix it for months and have so far been unsuccessful.

The lack of power is also accompanied by a drop in mpg, the hatchback does a happy 55 mpg on motorway driving (working it out at the pump) however the estate under the same conditions will only do 48.

The 2002 hatchback has 100k miles on it, and the 2003 estate has 68k miles on it.

I have tried everything i can think of, including the following:

Cleaned and tested EGR valve
Oil change
gearbox oil change
fuel filter change
cleaned the maf with carb cleaner
tested the boost pressure (using a gauge, its happy at approx 1.5 bar) - there are no leaks
taken out and checked intercooler
air filter changed
10k boost for diesels used
s**t loads of redex
tested all the sensors on the engine that i can (resistances according to dialogys)
new glow plugs
given it a really good thrash (followed by a new tank of fuel and an mpg test)
cleaned the intake manifold and stop valve
tested for vaccum leaks
tried adjusting the turbo wastegate actuator arm
checked the turbo shaft for play (its lovely and tight and spins perfectly)
checked the timing of the engine - its spot on.
checked for binding brakes
checked the tracking
checked the tyre pressures
waxed the bodywork (less drag) :d
checked for fault codes (none have ever occured over last 5000 miles)
disconnected battery overnight just in case ecu "learns" my driving style
tried driving it like a grandad to increase the mpg (didnt work) :crazy:

I have also tried swapping the maf, map and turbo control solenoid between the 2 cars.

Neither car smokes. Estate might see a slight puff of black smoke when accelerating heavily after sitting on the motorway for 200 miles or so, but i should image thats normal.

I have tried turning the egr valve 180 degrees as well - no difference

I have installed a chip on the fuel pressure sensor which has improved power but only up to the same level as the hatchback, mpg still remains at 48.

Nothing I do makes any difference at all, the estate is really smooth, idles fine, is amazingly quiet and smooth.

Its not a big lack of power, I would say if I raced them, the hatchback would probably hit 100 by the time the estate hit 70, so a fair difference. :devil:

Its not just the bhp that feels different, the estate seems to have less torque at lower speeds.

Sorry to be a bit to the point, this problem is doing my head in!

Can anyone suggest why the estate would have less torque, less power and less mpg than the hatchback that has more miles on it, and been through a turbo failer less than 1000 miles ago.

Could renault have made the ECU mapping different between the hatchback and estate?

I dont think it is weight, as the hatchback with 4 people in the car is still much better than the estate.

Could the areodynamics difference between an estate and hatchback really cause this much difference? Please Help :):confused:
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