I see from looking around here that the clientele are almost exclusively RWD, but very knowledgable, hence my decision to post here......
My wife's recently aquired an '05 R50 Cooper, but as I've become more familiar with the car I've realised that there's a subtle misfire going on.
I'm new to INPA, but I've had a look at the analogue readouts with the car in motion and strangely, the 'roughness' values remain quite firmly rooted to zero under load, rising a little on the over-run or at idle.
Knock sensor voltage seems quite erratic, jumping up and down all over the place (but perhaps that's normal ?) which made me suspect a faulty sensor, but disconnecting the sensor seemed to exacerbate the existing problem rather than a) curing it or b) creating a totally different one. - Interesting ?
I'm not getting any fault codes, I've already changed plugs & leads but I'd like a firm diagnosis before I fire more parts at it (coilpack next)
I'm thinking that perhaps erratic ignition, sensed by the knock sensor is being 'smoothed over ' by the ECU retarding timing to achieve quieter running, therefore when I disconnect the knock sensor, the 'smoothing' is removed and I get to feel the misfire in it's raw state.
Does any of this make sense, or am I doing the old 2+2 = 37 routine ?