R53 Unusual Problem - I cannot return from short journeys...

[Wilburo]

Hello chaps,

I'm having an unusual problem in our '54 R53. For the last three years, we have had the emissions light occassionally come on, following which the car will enter limp home mode if driven above approx 20mph.

However, the emissions warning light generally only comes on if you undertake a very short journey from cold, for instance the ten minute drive to Tescos... Shopping complete, the car will start with the emmission warning light lit.

If the emission warning light is on, one can cure it by driving around at <20 mph until the car fully warms up. Then, on restart, the light normally clears.

Having identified these circumstances, we've generally driven around the problem for the last three years (i.e. by not using it for really short journeys), so it's only being a problem on occassion.

I have previously taken it to a garage to investigate the errors, where it reported a "throttle pentometer error" or similar. However, the garage couldn't identify the cause of the problem, so they said to bring it back whe it happens again. That was about 18 months ago.

To me, it's something not warming up on these short journeys, which then errors when lukewarm on restart, but I have no idea what.

So, do you chaps have any suggestions as to what the root cause could be?

Thanks

[Steffan]

Take the car to a good rolling road/Engine analyser expert garage and they will identify the fault.

With modern engines ECU/Injection/Multipoint/Cam Sensor/Crank Ssensor etc etc electronic analysis on an RR is the only way to really be certain of the cause.

Could be a sensor, thermostat, or any one of a number of causes.

The days of guesswork are gone. Sadly