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Tony Yip - 06 Jul 2003 17:43 GMT

Dear folks,

Recently the engine of my car (95 Rover Cooper) always stalls when I want to
stop the car. When I depress the clutch pedal fully while the car is about
to stop, the rpm of the engine just drop straight to zero and the engine
stalls. The problem becomes more serious when the air-con is on. Any
suggestions on what would be the cause and how to fix ?

Thanks very much.

Tony

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Graham - 07 Jul 2003 04:16 GMT

> Recently the engine of my car (95 Rover Cooper) always stalls when
> I want to stop the car. When I depress the clutch pedal fully while
> the car is about to stop, the rpm of the engine just drop straight
> to zero and the engine stalls.

Will the car idle in neutral while stationary and with your foot off the
clutch?

Does putting your foot on the clutch when it is idling in neutral then
cause it to stall?

> The problem becomes more serious when the air-con is on. Any
> suggestions on what would be the cause and how to fix ?

I'm trying to work out if the problem is something to do with the
clutch, or the engine is simply not idling properly.

If it is the latter, and since the car is injected, the problem lies
with the idle solenoid or the wiring connecting it to the computer.
This is not uncommon in injected cars - often the idle solenoid valve
gets sticky and stops working properly, or the electrical connector gets
a little corroded.

If you can identify the electrical connector which attaches to the
throttle body, carefully disconnect it (there will be a locking clip of
some sort on it) and then reconnect it. This will often fix problems
like this.

Graham.

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Tony Yip - 07 Jul 2003 15:41 GMT

Thanks Graham, Fraggy and Barspeed. The engine is also not very stable when
idle, especially during the first few minutes after it is started.
Depressing/releasing the clutch makes no difference when the car is
stationary, also no problem when changing gears while the car is moving. The
problem only becomes acute when I am braking and depress the clutch at the
final moment before the car comes to a complete stop. It seems that at that
final moment the engine's rotation is purely sustained by the inertia of the
car so once the clutch is depressed, the engine loses its momentum
immediately and stalls. You guys are probably right that the idle control
might be the cause. However, as I am so naive about car mechanics and don't
want to make things even worse, I have taken the car to a garage today and
hopefully they will be able to find out what's wrong soon. I'll certainly
let you guys know what's the diagnosis later.

Thanks again for all the valuable advice.

Tony

> > Recently the engine of my car (95 Rover Cooper) always stalls when
> > I want to stop the car. When I depress the clutch pedal fully while
[quoted text clipped - 25 lines]
>
> Graham.

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Tony Yip - 10 Jul 2003 16:10 GMT

I have got my car back today, The mechanic said the cause was on the vacuum
pipe (I don't know what it is). He said he has replaced it and showed me the
old one. It is a very small black plastic tube, and I noticed that one end
of it is a bit melted. Can someone confirm whether this small black tube can
be a cause of the problem that I had ? or the mechanic is just fooling me ?
The car seems OK now anyway.

Thanks again.

Tony

> Thanks Graham, Fraggy and Barspeed. The engine is also not very stable when
> idle, especially during the first few minutes after it is started.
[quoted text clipped - 43 lines]
> >
> > Graham.

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Graham - 10 Jul 2003 17:32 GMT

> I have got my car back today, The mechanic said the cause was on the
> vacuum pipe (I don't know what it is).

Ahhh.
The vacuum advance pipe had come adrift and was letting excess air in.
Because it's a very small pipe, it doesn't let very much air in, so it's
really only enough to completely f.ck up your idle, whilst not really
effecting drivability.

> He said he has replaced it and showed me the old one. It is a very
> small black plastic tube,

That's right.

> and I noticed that one end of it is a bit melted.

It probably came to rest on the exhaust manifold.

> Can someone confirm whether this small black tube can be a cause of
> the problem that I had ? or the mechanic is just fooling me ?

It certainly can. Sounds like your mechanic is on the ball there.

> The car seems OK now anyway.

Excellent!

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Vern - 10 Jul 2003 20:43 GMT

> I have got my car back today, The mechanic said the cause was on the vacuum
> pipe (I don't know what it is). He said he has replaced it and showed me the
[quoted text clipped - 59 lines]
> > >
> > > Graham.

No, he's not trying to kid you !
The vacuum pipe goes to a diaphragm in the distributor and that,
combined with a set of weights on springs inside the dizzy, control
the advance curve on the ignition.
When there's a hole in it, or it's disconnected, because it's
connected to the intake manifold the engine draws air in through it,
bypassing the carb, so you end up with a very lean mixture.

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Tony Yip - 11 Jul 2003 16:30 GMT

> > I have got my car back today, The mechanic said the cause was on the vacuum
> > pipe (I don't know what it is). He said he has replaced it and showed me the
[quoted text clipped - 67 lines]
> connected to the intake manifold the engine draws air in through it,
> bypassing the carb, so you end up with a very lean mixture.

Thanks very much for your detailed explanation Vern ! Now I fully
understand.

Tony

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