TD4 slow reving / lack of power

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knobby

New Member
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Hi guys

Been having some issues with my Freelander Td4. Basically had some issues starting, and it feels like that car is holding back, not reving well. Also when on a trip, say im driving along for 5-10 miles at 60-70 then slow up for a junction, stop to a crawl and try and pull away in 2nd and it feels very flat.

well been reading up and found someone mention about the MAF and it being faulty and to try and disconnect it to see how it runs disconnected.

So I run out side, disconnect what I think is the MAF and the car runs perfectly, revs much better and feels like the car has loads more power, came back started reading up on MAF costs and see a picture of the MAFs at the back of the engine, what i've disconnected is at the front of the engine one the intact pipe, picture below..

What is this sensor?

motorvapor.jpg
 
Hi Knobby,
Fink you may have disconnected the boost sensor - see extract from Rave;
Boost Pressure (BP) Sensor >>
The BP sensor is located on the front side of the intake manifold and has a three pin connector. It provides a voltage signal relative to intake manifold pressure to the ECM. The BP sensor works on the piezo ceramic crystal principal.
Piezo ceramic crystals are pressure sensitive and, in the BP sensor, oscillate at a rate dependent on air pressure.
The BP sensor produces a voltage between 0 and 5 volts proportional to the pressure level of the air in the intake manifold. A reading of 0 volts indicates low pressure and a reading of 5 volts indicates high pressure. The ECM uses the signal from the BP sensor for the following functions:
> To maintain manifold boost pressure.
> To reduce exhaust smoke emissions while driving at high altitude.
> Control of the EGR system.
> Control of the vacuum control module
ECM supplies the BP sensor with a 5 volt power supply. The output from the BP sensor is measured at the ECM.
The earth path is supplied via the ECM.
In the event of a BP sensor signal failure any of the following symptoms may be observed:
> Altitude compensation inoperative (engine will produce black smoke).
> Active boost control inoperative.
> The ECM assumes a default pressure of 0.9 bar (13 lbf/in 2 ).

Disconnection may have brought the default settings in - if it made it better better then yours may be duff?
Could be a cheap fix? :)
 
Dunno? but mine looks just like that but not so oily :boink:
Front pipe on 06' vintage is just like that :):)

Did I get the sensor right?
 
Hi Knobby,
Well I did not get the sensor right !!! :wtf:
The pressure sensor is fitted into the side of the inlet manifold just behind the hoses. :der:
Fitted a set of new turbo hoses on mine today and that sensor in your piccy only has two wires and it is a temperature sensor (thermistor). :scratching_chin:
It is in the return pipe from the intercooler and so must be measuring the temperature of the "turbocharged + cooled" air being fed to the inlet manifold.
There's a picture of it in Haynes but no description, the Rave does not show it anywhere that I found (but as the Rave's 2003 perhaps it has been added later?)
The only air temp sensor from Rave is the IAT (Inlet Air Temp) sensor which is part of the MAF and it ain't that one!:confused:

Is Pardec's motor an earlier TD4?

Anyhow if that sensor is lying about the air temperature to the EDC then it could affect the fuelling and could still be a cheap fix (probably cheaper than the boost sensor) :)
 
My early (2000) TD4 doesn't have a setuplike that in the picture

but,

That short section of hose to the right looks blown out, and the oil behind it looks like a giveaway of a leak from it.
 
Hi all,
Had a look on Microcat (2007/8) for some info on that temp sensor?
It's listed as a 'Hose Assembly' P/No. PNH500190 - looks like it all comes assembled in one part (two bits of hose - two clips - one plastic short pipe thingy and the sensor fitted) THAT DON'T LOOK CHEAP !!!! :mad:
The earlier ones just have a single length of plain hose joining the intercooler to the inlet manifold. :rolleyes:
May be worth looking for some details of the sensor itself if that's the case.

If Knobby's experiment proves right and the power loss is down to a duff sensor then a scrappy part swap of the sensor alone may be a cheaper fix? :)
 
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