My 1999 E39 520i Touring had been stood, un-driven for some time. When I did come to run it, it started instantly but when the revs exceeded approx 3000, the engine virtually stalled and the ‘EML’ light came on. Upon restarting the engine the light would be off again but when increasing the revs, the same thing would happen.
Initially I thought that the ‘EML’ stood for ‘Engine Management Light’ and panicked but having read several forum threads I realised that ‘EML’ actually stood for something German and quite unpronounceable which related to throttle position and that problem was most probably related to the throttle body (TB) and/or associated hoses.
When I stripped back to the TB (TB still fitted to engine), I found that the main air intake rubber boot pipes were perished and both badly torn (I suspect that this may have been caused or made worse by an over zealous ‘professional’ car valeting, immediately prior to the car being stood up). Quite relieved, I replaced the boots and assumed that this would cure the problem. It didn’t.
I have now stripped back to the TB once again thinking that the butterfly may been gunked up and while it was certainly dusty (black) and would probably benefit from a proper clean, it didn’t appear ‘gluey’ but it is completely rigid (does not rotate or move at all).
Now I have three questions which searching the internet has not yet yielded answers:
1. After an ‘EML’ fault (and let's say the fault had been rectified by hose replacement), although the 'EML' light is no longer lit after re-starting, would there need to be some kind of external reset applied as with some faults?
2. With the TB still fitted to the car but ‘de-hosed and exposed’ should the butterfly valve turn when pushed or when the throttle cable is pulled - mine does not (I have not applied much pressure though as I am sure I had read somewhere never to operate it manually)? It feels completely solid to the touch and does not move/operate even when the throttle cable is pulled (with engine off and with ignition either on or off)
3. Is there any way of testing whether the TB is faulty or operating correctly while still fitted to the engine but without the air hoses fitted?
(I ought to mention, in case it's not clear from the above, that mine has a mechanical cable and not an electronic 'fly-by-wire' type throttle)
Any help or suggestions would be very greatly appreciated, I'm really groping in the dark.