Flusspferd

New Member
Hi everyone and Guten Abend from Germany

I’ve been reading in here since I got my 2005 td4 “Sport” about five years ago, by now I realized that the “sport” they seem to be doing in solihull must be something more like chess or replacing power window mechanisms against the clock, but I guess the car has its moments and I’d like to extend a big thank you to the fellow members sharing their knowledge and keeping these vehicles at least as roadworthy as the manufacturer intended.

I, too, have been underwhelmed by the power of the td4, especially when low in the ripp’Ems and towing my caravan during the summer, although most of the known troubles should have been shot already, including a fresh legit Bosch maf, full intake system clean, confirmed turbo operation and rigid boost hoses along with regular service. So I did what anyone on this forum would do and disconnected the maf (again) - and the car drove much better. Another duff Maf then? Checked it with another 35€ Chinese one from eBay and either that was bad out the box too, or there was more to it.

i had gotten an old code reader obd thingamajigger to clear the srs fault it liked to throw and read the data streams for rpm and air mass+temp with no maf, Bosch and Chinese maf. It turned out that the air mass increased with rpm similarly between all the setups, but without the maf, the engine assumed the highest air mass, while the two mafs returned similar (smaller) values.

Important to see is that with the maf disconnected, the ecu supposes the air entering the maf was at ~-40’celsius, when it was actually about +10’. The ecu therefore assumes the air was about 25% more dense so it oughtabeen injecting 25% extra fuel. Does that tell me if my mafs are good or bad? I say it doesn’t.

You don’t necessarily need a new maf or use a synergy if your car runs better with the maf disconnected.

The engine will always perform better if you disconnect the maf while the temperature is greater than -40,

because it injects additional fuel that would only be appropriate in -40 degree weather. Not sure why it was chosen like that, maybe being setup for -40 helps it start or idle/run if it does get that cold. So, as running something like the synergy could get you into lots of trouble in Germany, for now my way to go will be keeping a maf plugged in when my wife has it, and when i feel like it or need power to tow, unplugging the maf for xy% power increase and for whatever reason better throttle response.

Let me know what your thoughts are!
 
The Freelander Sport system is a styling feature, so it has 18" wheels, lower suspension and body graphics. There's no more power though. All the M47R engines in the Freelander make 112 BHP which by modern standards is pretty low.


If there's no air mass reading available, then the ECM substitutes a base setting, and disables smoke mitigation routine, which is why there's more power.

The intake temperature issue is due to the MAF sensor being combined with temperature sensor in it.
Unplugging the multi plug also disconnects the intake temperature sensor, so the ECM defaults to -40°C, which is a standard valve for a missing temperature sensor.

It is theoretically possible to disconnect just the MAF part but keep the temperature sensor component working, but you have to modify the MAF sensor to do that.
 
Last edited:
Moin Flusspferd,

That is an interesting observation. I wrote some weeks ago that I couldn't understand why when the MAF is unplugged it needs less fuel or at least not more as it is usually being said. I went on a trip to Germany with the MAF unplugged and it literally gave me same or very similar results to the time before, though not getting it down to 6l/100km/~50mpg at 95km/h/60mi/h speed (satnav), but that was probably due to the missing temp sensor then.
When changing the MAF did you give it a new air filter and did you clean the MAP sensor as @Arctic2 mentioned it somewhere?

@Nodge68 Would you know which wires to disconnect for the MAF and to leave in the ones for the temp sensor or would it better to cut out the contacts for the MAF and only leave temp. sensor in on an old one?

Matthias
 
Last edited:
Good morning
i have landrover td4 2005
my car problem no power DTC T21 Boost Air Temperature Sensor
Help my plz how fixit and where location the sensor Thanks
 

Similar threads