Re: Check engine light illuminated on 95 disco
> "MDH" <matt-at-matthosford.com> wrote in message
> > Anthony wrote:
> >> Thanks Badger. How does the idle speed control stepper motor work?
> > Anthony,
> > I had my Disco II in the shop last week for a check engine light. How
> > many miles on the vehicle? Has the truck been maintained, are these the
> > original plugs and wires?
> > Bad plugs and or wires will cause a check engine light. The vehicle
> > possibly misfired which would trigger the light.
> Matt, the misfire detection system and assosciated fault codes are only
> applicable to the Disco II, not Disco 1. The D1 has the Lucas 14CUX
> fuel-only management system, which is relatively basic in terms of fault
> monitoring, whereas the D II has full Motronic engine management and a lot
> more fault code info. FWIW, UK spec D II vehicles do not have the fault
> light activated within the ecu software, only US spec models.
> Anthony, the idle stepper motor is just that, a stepper motor controlled by
> the ecu. ECU see's an rpm value, decides if it is correct, low or high. If
> correct, it does nothing. If low, it opens a given number of steps. If high,
> it closes a given number of steps. In all cases, it constantly monitors rpm
> and when the target rpm is achieved it remains stationary. it's basically a
> stepper motor connected via a screw thread to a tapered port valve, but the
> whole gubbins can get gummed up with oily carbon residue, quite a common
The truck has around 157,000 miles on it and I seriously hope the plug
wires are not the originals but I don't know. Oil and filter changed
every 3000 miles but I really don't know the rest of maintenance
history. I will check out the stepper motor condition and vacuum lines
and stuff. Thanks so far