Am 15.01.2012 23:57, schrieb Rob. Smith:
> Roland Franzius<roland.franz
...@uos.de> wrote:
>> Am 11.01.2012 10:03, schrieb Rob. Smith:
>>> Not sure I have a problem, but when the car is cold (1st start in the
>>> AM), it idles too slowly and is very 'juddery'. Putting it in D helps
>>> a little (as the vacuum controlled ignition retard function is turned
>>> aff), but its still too slow when drive is taken up (at idle). It
>>> drives fine, so I feel the warm up regulator is richening it up OK.
>>> I have changed the electrically heated Aux air valve for another (not
>>> a new one however), but the effect is the same.
>>> When the engine warms through, the idle speed is ~800 and nice and
>>> smooth. Also the CO content is spot on at this point too.
>>> Can anyone tell me what their late 123 series 230E (or CE) does (rpm
>>> wise etc) when cold at idle?
>>> Any suggestions about what to check?
>> Have you checked the engine house vacuum? It is used to drive control
>> hoses and cold idling is bad if the crankshaft ring gasket is defective
>> or the vacuum hose from camshaft cover to intake manifold is closed by
>> oil debris.
> Thanks for the reply
> I am confident I have good vacuum. The 'economy' vacuum gauge reads
> good, and the vacuum retard system operates to the full extent at
> idle.
> When you talk of the 'crankshaft ring gasket', I am not sure what you
> mean. Do you mean the gasket under the oil filler cap, or are you
> concerned about blow by from the piston rings?
> As for the crank case ventilation system, you are correct in that I
> have not yet checked that. I used to own a W123 280E, and that had a
> blocked (oil debris) crank case vent. That would cause oil to be blown
> out of the dipstick tube till I fixed it.
> One thing I can tell you is that the idle bypass screw (idle speed
> screw) had to be unscrewed so much that there was a loud hissing noise
> from the air passing through it to make the engine idle properly. I
> have had to open the throttle butterfly flap slightly (adjust the
> throttle butterfly stop screw) to allow me to close (screw in) the
> idle bypass screw to reduce the noise from the idle speed screw area.
> This is porbably not what I should have done, but I can easily return
> it back to original.
> Thinking about the evidence I have, and your points, I think that I
> should make a full investigation of the crank case vent pipes and idle
> control pipework.
It is a little block at the left down on surface the crankcase. It is
an electrically heated themostat and intake vacuum membrane regulated
fuel bypass working for the first five minutes after cold start.
