Rover 200 & 400 Owners Club

Hi Rover people,

My faithful k-series 1.4 engine is running rich. This became apparent after noticing the MPG drop and struggling on MOT emissions. After lots trouble shooting, it seems that the lambda sensor is not working as the ECU lambda value is fixed at one value regardless of engine status. So this was replaced with a new one, twice, but the problem remains...

I have tested the wiring between the sensor and ecu and this is fine, so is there anything else that could be causing the fault? I am trying to avoid spending too much money, so trying to avoid the shotgun approach of replacing everything and hoping for the best.

The lambda value I am seeing is read using a app on my phone - so the other potential issue could be with the diagnostic app and not the lambda sensor... but i am relatively confident with the app as every other feature and sensor is working. Does anyone around Leicester have a 89-95 k-series rover 214 that I could plug my phone into to test this app??

Open to any ideas as it would be great to have it running perfectly again (on about 150,000 miles now and i want it to live forever!)

Cheers

Ivan

At 150k it may be more than just lambda, from failing injector o-rings to worm piston rings to who knows what.

If you have no record or a rebuild I think it’s done very well.

What version of MEMS, or what style of diagnostic connector do you have?

By lambda do you mean you are watching the voltage output from the sensor as a narrow band 02 sensor is only accurate at lambda 1? If so what voltages are you getting?

Thanks for the replies;

distance 1234, the engine has not been rebuilt yet - just looked after, I've owned it from 50,000 miles... and it was/is used for rallying too! :P agreed, it's doing very well.

crepello, I'm not sure what version of mems it is, but on the ECU is states MEMS MKC103020 0105, and it has the 3 pin diagnostic socket in the engine bay. It is a 1400cc K-series with 16v, MPI closed loop fuel/emissions control with cat.

johndq, I've not tried measuring directly the voltage output from the new sensors (I did with the old faulty one which was something too low - i might try again with the new one), but now using the diagnostic tool, which reads 435 regardless of engine state. It looks like the ECU is just using a default value due to nothing being received from the sensor/out of range.

Cheers

If that's 0.435volts on scan tool thats normally what the sensor puts out with engine off

Yes, it's 435mv so either 2 new lambda sensor's aren't working or ecu? Does the ecu use a default value of 435mv if the lambda sensor is unplugged?

Cheers