Phantom Revving

kinrsole · Unread post by **kinrsole** » 26 Feb 2005, 16:52

Whilst sat at the traffic light the other day the engine started to rev up and down on its own! It was ticking over as normal, around 850 rpm then revved up to 1500rpm then dropped back down to tick over. It did this a few times before the lights changed and then I drove off with no problem. It’s been OK since until this morning when I stared the car and the revs again rose up to around 1500 before dropping back to normal tick over.Other than this the car seems to drive as normal.
Anyone got any ideas as to whats about to go wrong?
Forgot to say the cars a 2.1 TD Xantia R reg with 94000 on the clock
thanks

Richard Gallagher · Unread post by **Richard Gallagher** » 26 Feb 2005, 16:56

What car/engine is it?

kinrsole · Unread post by **kinrsole** » 26 Feb 2005, 17:06

Forgot to mention that bit.[:I]
Must have edited original post as you where posting the question!
Its a Xantia 2.1 TD

Unread post by **alan s** » 26 Feb 2005, 17:08

You got biiiiig potential problems with any diesel doing that.
Often caused by dirty air filters although we haven't had any for a while, but it is possible for the engine to start to rev up to self destruct point. Even turning the key off will not stop it.
I'll lleave it to the diesel guys to tell you where to start looking (after the air filter) but a word of advice; don't drive it until the fault is found.
Alan S

oilyspanner · Unread post by **oilyspanner** » 26 Feb 2005, 17:15

partly blocked fuel filters can cause the engine to race, check your engine oil too, overfilling diesel engines is dangerous, make sure its between the marks,
Stewart

kinrsole · Unread post by **kinrsole** » 26 Feb 2005, 17:15

It's a week since this first happened and the car has been OK since,until this morning that is.I had heard about cars revving themselfs to death which is why I want to try to sort this out before anything too exciting happends.
Oil is between the marks.

Unread post by **alan s** » 26 Feb 2005, 17:21

Mate,
Don't get us wrong; it's not usually an expensive problem if caught before it all goes pear shape but it is serious.
There are a few reasons and I feel that once you find it, the cause will be fairly obvious, starting as Stewart and I have said, at filters.
Alan S

kinrsole · Unread post by **kinrsole** » 26 Feb 2005, 18:49

Thanks for the replies so far.
I've just changed the air and fuel filter both of which looked like they needed changing.
When I started the car up after the change and revved it up it did exactly the same thing.I did notice some air bubbles in the pipe coming out of the fuel filter,probably from the filter change.I turned the engine off and restarted it and everything is now back to normal, for now, with no bubbles in the fuel.Could these bubbles have causing the problem?
Any other things I need to check or is this a job for an expert?
If its a job for an expert can anybody recommend a citroen specialist near Blackburn?
cheers

jeremy · Unread post by **jeremy** » 26 Feb 2005, 20:50

Have you got the roto-diesel pump rather than a Bosch? The Roto diesel uses fuel pressure as part of its control - so if you get air in it you get revving. I think you will find loads of posts on the subject about a year ago.
Answer's simple - get the air out! Check all pipes and connections especially filter bowls. If you think you've still got air getting in replace the last bit of hose in the fuel supply to the injection pump with a piece of trans[arent pipe and look for air in it.
Incidentally leak-off pipes don't allow air back into a roto-diesel pump but do on a Bosch.
jeremy

oilyspanner · Unread post by **oilyspanner** » 26 Feb 2005, 21:38

Many years ago I read about CX diesels running away due to air bubbles in the fuel, there was a special filter element that was supposed to break up the bubbles or something, sounds like you are now on track, look for split fuel line sucking air if the problem continues.
Stewart

kinrsole · Unread post by **kinrsole** » 26 Feb 2005, 21:54

There is already transparent pipe from the fuel filter to the pump.
The bubbles where only there after I changed the fuel filter.Just driven 50 miles with no problems so I'm keeping my fingers crossed the problem was due to either the air filter or fuel filter.
I'll give all the fuel pipes the once over just to be sure.Not sure what type of pump I have
thanks for the help

yangreen · Unread post by **yangreen** » 27 Feb 2005, 01:11

My 306 Dturbo (non HDi) went through a spate of doing this and I never got to the bottom of the problem. I do occasionally get problems if I start the engine between 30 and 60 minutes after stopping or, more common, the revs really struggle or she stalls. I have checked the fuel primer (you know, the bulb thing) on these occasions and it has been soft. Is this also air/fuel line related or have I stolen someone's post for the wrong reason?

Kered · Unread post by **Kered** » 27 Feb 2005, 02:28

Do a search on the forum on "2.1 hunting". There have been lots of posts on this.
Derek

kinrsole · Unread post by **kinrsole** » 27 Feb 2005, 03:20

Just done the search.
I'll see how it goes but I'm guessing I'll need PART NO.1338 78 STOCK SENSOR ENGINE pretty soon
cheers

kinrsole · Unread post by **kinrsole** » 02 Mar 2005, 23:50

sorry for bumping this back up but the problem has come back.
I assume the part(PART NO.1338 78 STOCK SENSOR ENGINE) is dealer only so will order tomorrow.
How big a job is it to change and where exactly is it located.Is it one of the two in front of the fuel filter?
thanks