The missus car (MGZS 1.8 KSeries) has got a bug.
Leave her on tickover and the engine revs to 3000, then back to 2 then back to 1... wait a few seconds then up to 3 and so on.
Up and down the scale like a mechanical Mary Poppins! Quite spooky standing outside the car watching it.
I get a puff of white smoke when it hits the 'high c' and a small backfire which suggests that its metering too much fuel.
Any suggestions? apart from entering it into Eurovision?
Air idle valve??
I was thinking maybe the TPS sensor giving a false signal to the ecu to deliver more fuel.
The overrich mixture condenses in the inlet manifold, backfires causing the MAF sensor to shut the fuel delivery down. then it starts again.
The odd thing is the rythmic cycling. Its got to be some kind of circular process.
Check the inlet manifold is tight and sealing against the head, clean the idle control valve with carb cleaner and re-synch the valve by putting the
key in the ignition and with the drivers door open turn the ignition on but don't start the engine then depress the throttle pedal fully and let
it back up slowly 10 times.
If that dosen't work read the fault codes.
quote:
Originally posted by plentywahalla
I was thinking maybe the TPS sensor giving a false signal to the ecu to deliver more fuel.
The overrich mixture condenses in the inlet manifold, backfires causing the MAF sensor to shut the fuel delivery down. then it starts again.
The odd thing is the rythmic cycling. Its got to be some kind of circular process.