Engine sensors on Rover 45 SDi

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DRover620
Bolt Twiddler
Posts: 26
Joined: Wed Mar 11, 2009 8:01 pm

Engine sensors on Rover 45 SDi

Post by DRover620 »

My friends Rover 45 with a SDI engine is loosing power for the last 15 days. Not long ago the car was on the service with the oil, filters and MAF replaced. Last night he removed the protective cover from the engine to see that there are no wires connected to the air inlet temperature sensor located on the inlet manifold.
Now I know that on later L-sefries there is a air temperature sensor in the MAF, then what is the purpouse of this (unpluged) one and do the ECU combine the data from the both to calculate the ammount of the fuel needed?

On second thought: someone didn't replaced the MAF and instead just unpluged the sensor on the inlet manifold to fool the ECU and make the car faster?

Thx,
Dule
E_T_V
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Posts: 439
Joined: Thu Jan 29, 2009 9:38 pm

Re: Engine sensors on Rover 45 SDi

Post by E_T_V »

If the engine is still running the 45 engine management and fuel pump then the unplugged air temp sensor is normal. It was cheaper for rover to fit a sensor than to make a blank for it!

If unplugging the MAF sensor improves the low down power but reduces the high rpm power then the MAF sensor is most likely out of spec.
If unplugging the MAF sensor makes no difference at all then the MAF sensor is totally faulty (or there is a wiring fault to it).
If unplugging the MAF sensor makes no difference to the low rev power but reduces the high rpm power then the MAF sensor is functioning perfectly normally.

(Unplugging the MAF sensor makes the ECU run on a conservative default set of fuelling values. These provide ok power low down but limit the power high in the rpm range - most engines won't rev past 3700rpm with the MAF unplugged/faulty).
DRover620
Bolt Twiddler
Posts: 26
Joined: Wed Mar 11, 2009 8:01 pm

Re: Engine sensors on Rover 45 SDi

Post by DRover620 »

Thx for the reply, it looks like it is a dead MAF then :(
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