My 1994 plus 4 has a persistent fast idle issue. It idles at about 1050 rpm. I’ve changed the temperature sensor - no difference, checked all hoses etc. By way of this forum I know that the baseidle is set in the ecu but have no means of connecting to it. Is an ecu a straight swap! Should I take it to a dealer or just change the ecu? I should add that other than the idle the car runs and starts fine. What does the collective think?
Changing the ECU will unlikely change anything, though who knows? Do you have a diagnostic reader?
The Rover T16 idle is controlled by the throttle plate and a stepper motor, working together. For example, if the throttle plate is dirty and cannot move freely it will not allow the stepper motor to reset itself. Stepper motor problems alone usually will cause wrong cold idle speeds aka too fast. So start by cleaning the throttle plate (aka the butterfly).
You can also buy a spray bottle of ether https://www.amazon.co.uk/Holts-Bradex-Easy-Start-300ml/dp/B000X2CR4W/ref=sr_1_1?crid=1WR3FCE1SIOVA&keywords=ether+start+spray&qid=1696862898&sprefix=ether+start+spray%2Caps%2C235&sr=8-1 Use it to spray around your engine hoses while idling. If your idle changes, you have fond your culprit. BTW, ether spray is a great brake and fueling part cleaner as it completely evaporates after a few moments.
L.
