specalist knowledge in 1.9TD xantias and idle speed.

[MikeT]

Of course it could be the pump causing this problem but I'm struggling to imagine how, given the circumstances of when the idle rises. I am convinced it's a mechanical, not electronic issue though.

The fact the throttle cable has been disturbed at least twice suggest it's the likely suspect, especially if it caused or required resetting of any or all of the other throttle/damper/idle stops etc.
Setting a diesel pump is a black art to many workshops, best left to a diesel specialist - and that includes fitting a new cable imo. Even the routing of the outer shielding has to be exact - long gentle sweeping curves for instance.

Having said that, diagnosis should be a doddle as suggested in the above posts. Wait for high idle to occur again and see if manipulation of the throttle cable/stop cures it. Overthinking this seems to be confusing the issue unnecessarily.

[falling-out-with-my-car]

have just been down town 12 miles and the car started playing up again.
couldn't open the bonnet though as I have ratchet straps holding up one end of my smashed front bumper.
However it dawned on me suddenly that years ago I used to drop the throttle adjustment back a couple of notches
for the MOTs as the tester always revved the engine a lot and I didn't like the sound of it much.
So I'm going to drop the adjustment 3 notches soon and see if it makes a difference.
I cannot tell if the notch position was changed when the new throttle cable was put in but I suspect it was.
I completely forgot about this.

[CitroJim]

Good thinking Nigel. I found the throttle cable is best having a bit of slack in it...

Fingers crossed that's the problem. It could certainly cause it...

[falling-out-with-my-car]

Ok so car repaired and back on the road, I now have a temporary throttle return spring in situ to keep the revs down
when the engine gets hot in traffic.
Last time the revs climbed I popped the bonnet and pushed back the throttle lever to its stop.
so there we have it something is impeding the travel of the throttle stop when the engine is Hot.
a temporary return spring seems to bring the throttle back to its original position every time.
although it does make the throttle seem a little heavy on the foot, it is also causing a bit of faff on corners
with the throttle closing so quickly I seem to loose inertia and revs and have to change down a lot.

so I'm suspecting the throttle cable casing here.
or the spring in the drum on the throttle cable.

regards.

Nigel.

[Harlequin]

if its a bosch pump iirc its supposed to have a mini `shock absorber` on the front and a spring assembly on the rear anyway

[CitroJim]

The spring in the drum could be the issue Nigel. It can be bypassed without harm.

As Simon says, if the damper is still in situ then bin it quick.

[falling-out-with-my-car]

Never had a damper on mine at all.
so to clarify the drum on the cable is what your talking about?
I've a feeling as I've only had my throttle cable replaced by garages
they have only ever changed the middle core of the cable.

If I put in a new cable and casing can I not fit the drum?

[elma]

The dampers are awful, get rid if its still there. They just waste diesel by slowing down the release of the throttle.

The drum spring totally ruins the accelerator if worn, well worth a check.

[falling-out-with-my-car]

to check the cable adjuster drum I'm going to remove the throttle cable from the pump
let the engine heat right up then blip the throttle to see if it maintains the high revs.
if it does its definitely the pump as the throttle cable wont be connected.
if the throttle behaves normally then its probably the cable at fault.

I don't know why I didn't think of this sooner it seems such a simple test
fortunately it came up in conversation whilst I was at Pleiades yesterday.

regards.
Nigel

[falling-out-with-my-car]

Ok I have been running my Xantia 1.9TD for a while now with the
vacuum pulling on the pump cable, now she seems to be blowing white smoke from the exhaust on acceleration
but running at 50-60- 70mph there is no smoke.
I am wondering if this is being caused by the permanent vacuum setup.
lowering the idle speed.
could this have an adverse effect on the fuel air mixture?
I checked the air intake no oil in it, I replaced the air filter and changed the oil.
I'm still getting white smoke on acceleration particularly so when the engine is cold.
It may be time for a new motor. the head gasket was done 4 years ago at Bourne Citroen.
miles on the clock 186K, have already tried an Italian tune up which seemed to clear the smoke problem but it was
back again the very next day.

any ideas please.

Regards.

Nigel.

[CitroJim]

No, it'll have no effect at all Nigel...

White (or grey) smoke is incomplete combustion of the fuel. Top causes are a bad injector or low compression on one or more cylinders... You may have a tight valve...

As a guide, black smoke is combustion lacking in oxygen due to breathing issues such as a lack of turbo boost, blocked air filter, collapsed turbo ducting and so on...

White or grey: as above..

Blue: oil being burned.

[white exec]

White smoke, on acceleration, also caused by a coolant leak into combustion chamber - ethylene glycol/antifreeze burns white. Can often be detected by a sweet smell to the exhaust. Indicates a head gasket leak.

[CitroJim]

Chris, never knew that.. What I love about this forum, something new learned every day

Great diagnosis tip too... Unless you're running on veg and then the exhaust smells sweet anyway...

[superloopy]

Would you expect white smoke if one or more glowplugs a bit iffy?

Sent from my LG-D855 using Tapatalk

[CitroJim]

Would you expect white smoke if one or more glowplugs a bit iffy?

Only on a cold start Mike... Once the engine is warm the glowplugs have no effect...