Has anyone ever heard of this? (bosch Diesel Pump)?

[falling-out-with-my-car]

Hi, yes its my popullar 1998 citroen xantia 1.9TD SX yet again.

I have been doing some driving and yet again the throttle seems to be sticking when the engine is warmed up.

I have opened the bonnet and found that the throttle arm on the Bosch diesel pump is not going all the way home,

a new cable has been fitted and there was no damage to the old cable when it was removed,

I added an elastic band to the throttle arm as a temporary trial and the problem goes away.

The throttle arm almosty returns home it just stops short maybe only 3mm from the throttle closed position

This keeps the revs at about 1100rpm when the engine is warm. I am tempted to make a light external return spring of some kind

but I am not sure if it will do any damage.

it would seem that my throttle return spring is knackered although it is stiill in one piece.

any thoughts?

regards Nigel.

[CitroJim]

Has it still got what looks like a black gas strut on the side of it Nigel?

If it has then throw it away!!! All your problems will then be over..

[falling-out-with-my-car]

Hello Jim,

unfortunately the gas strut went before I bought her
The throttle is a little low when idling cold it starts sticking when she is warm
idle speed at cold idle is about 700 which seems low to me. if I blip the throttle just after start up she ticks over at about 850 rpm.
I had the auxilary belt replaced recently by pleiades and he fitted 2 new tensioner pulleys and tensioner spring because the old one was rattling but I believe it was only rattling because the idle speed was to low open the throttle only slightly and the rattle went away the new tensioner spring rattles when the engine is cold at startup as soon as she is warm the rattle stops,

I have been so worried about not being able to sort this throttle issue Ive had the car almost 9 years now
how many people have a new motor that long let alone a used one
Ive even pondered letting go recently for a 2000 petrol piccasso which is cheap and cheerful and in need of an alternator.
she flew through the MOT this year back in Feb as usual so I hang on to what I know. I doubt I shall ever find a car as comfortable as this again.

[CitroJim]

Nigel, you might also look at the anti-stall damper at the back of the pump as that could be stiff in action too. It looks like a vacuum capsule and yu'll see the inner end of the throttle lever makes contact with it towards closure.

It's to give a soft slow action as if it wasn't there and the throttle suddenly snapped shut the governor would over-run and cause a stall..

[falling-out-with-my-car]

Yes i know the bit you are explanning it looks like a brass diaphram , the centre is red rubber with a spring in the centre, is there anything |I can do to free this up a bit if it is stuck. or is it replaceable, I did wonder if it might be this causing the problem.
either that or the vacumm choke mechanism sticking or not working properly. there are two electric switches on the bulkhead could these be mal operating or sticking open keeping the throttle high when warmed up? but not activating when the engine is cold keeping the throttle low below normal idle speed? could the vacumm pump be faulty?

regards Nigel.

[CitroJim]

That's the one Nigel...

It won't be the vacuum operated fast idle control as that's very much binary and has only two positions and speeds. Normal and fast idle..

[wotwot]

A quick hi to jim not been on for some time, had an operation on my shoulder in january and have been off the road till about 2 months ago.
Anyway I have a non turbo 98 dispatch with bosch pump, I have a sticky throttle too, But I was going to put it down to me running veggie through her.
I also checked the damper and cable but they came up ok.
I wonder if its worth putting some sort of injector cleaner in the tank to not only clean the injectors but the pump internals as well.
On a side note mine sticks when its cold or warm. She never did it prior to me laying her up for about 7 months.

[falling-out-with-my-car]

at last somebody that knows what I'm on about, appolagies wot not I'm not wishing this on you at all but it seems to be a rare thing.
Ive just had the matrix replaced on the xantia all new spheres this year and recently had the top and bottom pulleys done with the Auxillary belt she is due 2 tyres soon and a clutch probably within 20,000 or so but I am weighing up selling her on now and buying a C3 xsara picasso istead. its a shame but she has been a great motor for 9 years and never failed on the state of the bodywork or engine. the new tensioner on the auxillary belt seems to be rattling now its only been in the car a fortnight, I'm going to see if the belt needs retensionning and maybe it will silence it. the picasso's become more attractive with every passing day. I did have issues changing gear in the cold winter snow but that went away as quickly as the snow disappeared its been fine for months.
good to hear your over your Operation and back behind the wheel again.

regards Nigel.

[falling-out-with-my-car]

That's the one Nigel...

It won't be the vacuum operated fast idle control as that's very much binary and has only two positions and speeds. Normal and fast idle..

Does this ever malfunction though Jim?
as I said above the fast idle doesnt seem to be working when the engine is cold.
could it be comming on to late or when the engine is hot instead of cold making the engine idle to fast?
regards
Nigel.

[KP]

Falling out, have you tried running some normal diesel they her and see if the symptom persists? I'd run the tank right down and stick 10litres in and then do the same again as it will flush the veg out quicker.

As another member who has run on veg the things I have come across in the past seem to have been mentioned.

I removed the damper
I then elastic banded the bounce back damper as I called it
Adjusted off boost fuelling
Ran veg! Though at least once in each car when I did the first service after running on pure svoni changed the fuel filter and filled it with diesel fuel cleaner type stuff. Never noticed a difference but for £2 thought it worth a shot

[falling-out-with-my-car]

Kp,

sounds like you have been running neat veg oil, I havent been able to do that for a very long time
My S2 xantia
had issue last year with the nuber 3 cylinder lift sensor jamming, apparently the ECU takes a reading between the TDC sensor and the lift sensor to balence the ignition timming and advance ignition as you acellerate, I gave up running neat veg back then and went back to straight diesel at least until outside temperaturtes increased to above 20 degrees C then I started using a 50/50 mix she has been running fine on this 50/50 mix all summer long I drained it all out just over 40 litres a week ago and half filled the tank with straight diesel put in a new fuel filter and filled the filter housing with Diesel magic injectior cleaner which is what I do just before an Mot the problem with filling the filter housing with injector cleaner is that two thirds of it end up going back to the tank in the return lines so it doesnt really do the engine much good, if you were to put the injector cleaner in a clear plastic bottle then connect it directly to the pump you would be able to see just how quickly the level goes down and we are talking less than ten seconds if you open the throttle a couplke of times, as most if it is pumped to the fuel tank, I guess this happens so that the fuel in the tank is pre- heated by the pump for winter running. I am beginning to wonder if my timming belt has slipped a notch of if the pump was unbolted to get to the glow plugs for replacement and maybe it was moved slightly.I simply dont understand why it is behaving like it is.

[KP]

If you suspect timing is off a little then its best to get it sorted by someone who knows how to time them up.

While the electronics on it do so much they cant go beyond a very limited range. A lexia would show this up im sure as an error so possibly worth seeing if anyone local can spare some time to check the engine ecu for faults logged which may not flash up on the dash.

I ran all of mine, even a late s2 on a V plate on neat veg and all sorts and they just carried on going. Best was the doncaster floods where i turned the airfilter houseing 180' and went through some lovely deep floods that were stranding other cars although the water going over the bonnet a few times did worry me but it gave the engine bay a good clean and the underbody!

If a lexia points to nothing you need the likes of Jim or such like down your way to have a nosey over it or a Bosch specialist thats good with diesel timing.

[Xaccers]

Couple of thoughts Nigel, and apologies if I go over old ground:

1. In the past, have you swapped over the vacuum feed electrovalves, the fast idle and EGR ones?
2. When the engine is cold, have I read it correctly that it idles at about 700ish (then when warm increases)? If so, can you pop the vacuum tube off the back of the pump and confirm:
a) Revs increase to approx 1100rpm.
b) You can feel a vacuum from the pipe.
c) when the engine is warm and revving high on its own, if you pop the pipe off again, is there vacuum there.
3. Did you have the lift sensor injector cleaned professionally or did reverting back to a thinner fuel mix resolve the issue?


Timing won't cause the car to rev faster.

[falling-out-with-my-car]

Hi. Xac and thanks for joinning in,
answers to your questions.
!) I have never swapped the Egr and idle pipes over but the car did go to Barrys at bourne citroen to have the heaterr matrix replaced and this is when the problems started with engine idle speeds.
the vacumm pipes seem to all be interlinked above the switches on the bulkhead ie they have a t-junction joinning them all together, I did find a split in the pipe comming from the vacumm pump and repaired it by trimming back the pipe and re-attaching it.

2) your description in Number two above is spot on. I havent checked for vacuum yet but will do and let you know.

3) the injector lift sensor free'd itself when I reverted back to regular diesel, I didnt drive the car just let it idle for about half an hour on regular diesel. I also cleaned the wiring connector from the no 3 lift sensor with switch cleaner and it seemed to make a difference.
to sumarize yes the idle speed when cold is very low almost at stall speed, if I rev the the engine it picks up to about 900 rpm
and stays there but once I spend a few minutes in traffic engine hot the idle speed wants to run away to 1100rpm, new throttle cable has been fitted by Pleiades to no affect cable to throttle lever is not catching on anything at all. I currently have an elastic band on the throttle lever arm which seems to stop the throttle idle speed running away to 1100rpm the idle speed is still to low when the engine is cold 700rpm and is about 900rpm when hot with the elastic band fitted,

I will check for vacuum (engine hot) and report back.

I am concerned that the egr and idle vacuum pipes do not seem to be seperated all the pipes connect together with a plastic t-junction. Maybe the switches just need some switch cleaner on the connections? ive got to get on top of this one before the cold weather starts to creep back in again it can be minus 18 here in the winter.

Thanks
Nigel.

[Xaccers]

My thinking is; the revs you've mentioned fit with the fast idle speeds (700 ish when hot, 1100 ish when cold).
When vacuum is applied the revs drop to 700, when there's no vacuum the revs should increase to 1100ish. Many Xantias of our cars' age suffer from a fast idle due to the vacuum not working for some reason (pipe split, electrovalve faulty etc).

Now, if memory serves a pipe should come from the vac pump on the end of the cam to a T/Y piece and then to the two electrovavles. Then from the other port of the valves one goes to the EGR and the other to the fast idle. Off the top of my head I believe there may be a 3rd port on the valves to allow air to pass to the pump when the fast idle/egr are isolated but don't quote me on that, it's been a while since I've looked at the electrovavles in Cassy!

I'm sure some people have posted about swapping the valves over to test if one has failed, but on Cassy the electrical plugs are different so this isn't possible. Not sure on S2 cars, if the plugs are the same then they could have been inadvertently swapped over.
Likewise if the pipes from the valves to the idle/egr were disconnected, they could have been easily swapped over by mistake when refitting.
This is presuming the valves etc were touched when the heater matrix was done, it could also be that the idle's electrovavle is faulty (then again I could be completely wrong).

The symptoms you've describe sound to me like the fast idle valve is being told to open and close with the wrong conditions but they might be the right conditions for the egr valve to be activated.

So that would be from it being connected to the egr valve (or if possible electrical connector), or the valve being faulty somehow.

I look forward to hearing the next instalment of this saga