Diesel Xantia over revving

andmcit · Unread post by **andmcit** » 09 Jan 2007, 22:42

Ok, I'm sure I've read about this before but I'm damned if I call recall where:
my 1996 216k mile Turbo Diesel 1.9 estate has started to hold it's revs high
when I decelerate on the overrun/change gear etc. It's a real pain as it sounds
like I'm a learner driver when it appears to over-rev on gear changes!!

There's no branding to say what breed of pump I've got fitted but I can just
about make out Made in Germany so 'assume' it's a Bosch - are the RotaDiesel
and Lucas units made there too!? I've checked the obvious strut damper on the
front of the diesel pump and it seems quite free. If anything the main culprit could
well be the actual cable although there's a small flying saucer damper at the rear
of the pump which may be a bit slow on it's rebound - it's difficult to check for
more than a few seconds as the heavens have really opened here and I may
just look out for Mr Noah2...

What's the black canister on the middle of the cable in the engine bay that's
clipped onto the side of the battery holder? It's on TehAgent's picture on
coordinates J/K8 in his 'know your engine thread!

Is this anything as it's obviously inline with the main cable and it looks as
though a bared part of the metal outer bowden cable is rusting?

Any suggestions?
Andrew

andmcit · Unread post by **andmcit** » 09 Jan 2007, 22:45

One more thing - it may be me - the car seems to be low on performance
compared to an identical car I run too. Was going to check sealing of the
pipework etc when/IF it stops raining...

Is this significant to the whole poor cable idea? On PR Net it's not obvious
which one I need, and for once 16GBP doesn't sound a silly price from
Mr Citroen...

again, amy pointers?

Andrew

skysurfer1 · Unread post by **skysurfer1** » 10 Jan 2007, 18:34

Can't really help you with this, but I did have a test drive in a 1996 Xantia TD and it had the problem you describe. As you go up through the gears, each time you back off the accelerator and press the clutch the engine revs up. It's like the damper is really damping the release of the throttle, particularly at high throttle settings. This is unlikely due to the way that the damper is fitted at an angle, it's almost vertical at high throttle and so the damper can't be doing much until it has almost backed off to idle.
I took a brief look at it but beat a hasty retreat as the seller was threatening to smash up my car when I asked him if he had any proof of ownership

I would suggest that oil in the throttle cable has attracted dirt and become sticky, but thinking about it, it still did the same if the throttle arm was moved on the injector pump and I think doing that just bends the cable rather than feeding the cable in/out of the cable sleeve.
My 1997 Xantia TD SX 160,000 doesn't do this. Even befor the injector pump died a couple of weeks ago

As I said - sorry not much help!

Alan

Stewart(oily) · Unread post by **Stewart(oily)** » 10 Jan 2007, 19:46

I removed the black damper from my 98 Xantia because it was doing this,I still have not replaced it, what goes on in the black blob part way along the throttle cable? mines clipped to the side of the airbox, I think its another spring damper?
Stewart

tonyb1 · Unread post by **tonyb1** » 10 Jan 2007, 20:12

Sorry Andrew, but I have a completely unrelated question to ask and I need to use your great map grid, I cant add pics to my posts

. It's hard to explain the location and your map is a god send

There's a small pipe held with a jubilee clip in the bottom left of square 2E. Can anyone tell me what it does. My pipe has split, over two weeks now, but it hasn't affected anything

Thanks!

f00lzz · Unread post by **f00lzz** » 10 Jan 2007, 21:03

Stewart(oily) wrote:I removed the black damper from my 98 Xantia because it was doing this,I still have not replaced it, what goes on in the black blob part way along the throttle cable? mines clipped to the side of the airbox, I think its another spring damper?
Stewart

1. Yes remove the black damper.. it is surplus to requirements and prone to sticking!
2. I think the black blob is something to do with 'guiding' the cable without allowing it to vibrate against the airbox... mine is missing

davethewheel · Unread post by **davethewheel** » 10 Jan 2007, 22:23

can't help you there i'm afraid but i've got the same problem on my 2.1td you have to come of the gas just before you dip the clutch or the engine revs will rise, mines got the dreaded lucas epic pump so my problem could be a bit more complicated, i did however disconect the damper on my old 1.9td and it was much better to drive (the revs were always sluggish to drop back down) , no idea what the black blob is i can't recall mine having one.

andmcit · Unread post by **andmcit** » 11 Jan 2007, 00:04

If the gale actually receedes and I can actually stand in front of the
engine for more than 10 seconds without being totally soaked, I'll try
undoing the strut type damper [D7ish on the pic] on the front of the
pump. I agree with your thoughts though Alan, regarding the bending
of the cable rather than actually feeding it up the main bowden cable.

The damper is backed up with a mushroom/flying saucer compression
damper positioned on the back face of the pump and not shown in the
picture, and I feel these both have the joint effect of returning the
spring through the pedal. It may simply stay pressed down if I go
undoing all of them!!

I don't like the tight kink and the rust on the entry to the black 'blob'
on the side of the airbox and wonder if this has a direct influence on
the inner cable's movement.

I'm not even totally certain which cable I need to price up as there
seems to be a bit of guesswork in allocating what's what on Citroen's
parts database...

Any ideas - can't use the car really and it's just started doing this
Monday morning...

Andrew

andmcit · Unread post by **andmcit** » 11 Jan 2007, 00:09

tonyb1 wrote:Sorry Andrew, but I have a completely unrelated question
to ask and I need to use your great map grid, I cant add pics to my posts
. It's hard to explain the location and your map is a god send
There's a small pipe held with a jubilee clip in the bottom left of square 2E.
Can anyone tell me what it does. My pipe has split, over two weeks now,
but it hasn't affected anything Thanks!

Go ahead, it's not mine but another listers' intended for this very purpose!!

My guess is a breather pipe scavening oil back to the pump from the
induction piping. I think it'd be worth replacing it if it's split as I guess
Citroen didn't just put it there for the hell of it!!

Every component costs dosh and someone's time to fit - don't think
they'd miss a chance of saving 2p per car when they're selling 100,000's
of cars!!

Andrew

KP · Unread post by KP » 11 Jan 2007, 08:43

Im sure that pipe is the boost pressure sensor for the diaphram in the Injection Pump if you follow it along

Wont cause too much bother unless you boot it a lot and then the pump wont fuel the right amount and would run lean and you would also leak boost pressure as well from the system.

skysurfer1 · Unread post by **skysurfer1** » 11 Jan 2007, 13:45

tonyb1 wrote:There's a small pipe held with a jubilee clip in the bottom left of square 2E. Can anyone tell me what it does. My pipe has split, over two weeks now, but it hasn't affected anything

As KP said this is the turbo boost pressure monitor to the injector pump. With this split you won't get as much fuel injected as you should at full turbo boost. This will have no effect at all below about 2,000 rpm as the turbo isn't generating any pressure below that speed.
All this means is that you won't get quite the full flat out power that you should be getting. Perhaps your driving style doesn't make much use of "flat out"

With the tube just being split rather than disconnected it is probably still doing most of what it should do, depending on the extent of the split.
It isn't doing any harm in terms of "running lean" as there is no such situation that applies to a diesel engine. You just aren't injecting all the fuel that you could at maximum turbo boost and therefore you aren't getting full maximum power.
At idle, you will be sucking in a tiny amount of un-filtered air into the inlet manifold through the split. Not really enough to worry about. At full turbo boost you will be spilling air from the split - no harm done here, you're just loosing a tiny bit of potential power.
It doesn't need urgent attention but it will only get worse so when it's convenient, replace it with a similar length of tube and two hose clips.

Alan

tonyb1 · Unread post by **tonyb1** » 11 Jan 2007, 20:04

Thanks guys, much appreciated

. I'll do it at the weekend.

andmcit · Unread post by **andmcit** » 11 Jan 2007, 20:26

Righto, it's actually STOPPED raining...

The front telescopic strut/damper on the front is fine and moving freely.
The rear mushroom damper moves smoothly and isn't sticking. It looks
like the main culprit is actually the cable itself. I tried swivelling the
diesel throttle arm and pulling the cable and can hear a moving 'judder'
in the air box black 'blob' - it could even be this that may be causing the
sticking although it appears to be a main part of the cable.

Looks possibly as though I will need to buy a new cable. Thing is which
one!? I'm not clear from the vague listing on Citroen PR net...

Andrew

jeremy · Unread post by **jeremy** » 11 Jan 2007, 21:06

Have a look at the GSF and Eurocarparts on line shops. Kits are more fun than a dedicated cable as you have to assemble the thing yourself - having done one on our ZX I'd say make sure that you get any cutting of the rubber outer support at the accelerator end before you clip the inner to the pedal.

BrianM · Unread post by **BrianM** » 12 Jan 2007, 14:46

Replaced the cable on my 97 Xantia TD with a GSF kit one - if the outer cable is still ok you can just use the inner cable as the connector for the pump end is held to the cable with a small screw. Easier than trying to dissamle the existing cable to get the black springy thing off.

Brian

97 Xantia TD