Xantia speedo at 50mph

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SimonT
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Xantia speedo at 50mph

Post by SimonT »

Hi all. I have a wierd fault on my speedo. It doesn't read correctly at lower speeds but then jumps up and stays at 50mph whatever speed I do after that. When I slow down and stop it drops to 0 again and then when I pull off, zooms up to 50mph.
If I bash the dash like a maniac, it'll read ok for a few seconds and then go to 50mph!!!!!
Any ideas? I've heard there's a speed sensor for these electronic speedos but it seems more mechanical if it can be bashed, what you think?
God, it's annoying and confusing.
Saxo 1.5 XD 1998
(previously owned Xantia 1.9 TD sx 1995)
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Post by jeremy »

I think the meter will be a moving coil type of analogue meter - ie a voltmeter in effect - and so its mechanism will be fairly simple - ie a suspended coil. I would have thought it more likely that the fault was an electrical connection and would suggest that both the instruments connections to the circuit board and the board to loom plugs be cleaned first.

If you have a meter you may be able to test the drive sensor by metering its output. They used to be a small generator - but I'm not sure what the Xantia used.
jeremy
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Post by RichardW »

This is a knownfault with Xantia speedos. Unfortunately I can't remember if it's the sensor or the clock that's at fault :oops: I am leaning towards the clock from memory, a forum search might bring something up, but then again.... Neither part is particularly easy to change of course. Mind you, if it's a 1.9TD, then the speedo is large redundant any way - just drive on the rev counter, 10, 20, 30, 40, 50 mph at 2000 rpm in gears 1-5 respectively, means no tickets :lol: . I largely ignore my speedo - it tells porkies anyway - an indicated 85 at 75 for instance... :roll:
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Post by Peter.N. »

I havn't experienced this exact fault but would be inclined to lean towards the sensor or its connections. There is a two pin connector on the gearbox end of the cylinder head which plugs into the sensor leads, check clean and grease. The sensor is in the top of the gearbox housing, just above the flywheel.
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Post by RichardW »

"The sensor is in the top of the gearbox housing, just above the flywheel"

No, the speed sensor is on top of the output housing for the RH driveshaft, barely accessible from under the car. I had a thought - if the odo is still counting the miles, then it's a problem with the speedo head - and I'm leaning more towards this, as ISTR that most other people have had to change the speedo...
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Speedo head

Post by paulbx »

I had same problem on late BX TD. IT was the speedo head had become worn because at some time the cable had been incorrectly inserted and had worn the socket.
Solution - breakers yard and replace instrument binnacle wholesale
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Post by Peter.N. »

Sorry! :oops: :oops: :oops: I read 'speedo' and for some reason or other, my brain interpreted it as 'rev counter'
philhoward

Post by philhoward »

When the speed sensor went on my Xantia, it would read fine below 50mph, then go absolutely bonkers (0-130mph); drop the speed and it behaved again. Finally gave up a couple hundred miles later...and the odometer stopped (that's probably the clue to sensor or clock)

A single bolt holds it on (only) locatable by feel..and if you go searching the scrapyards, make sure the number on the top (something like 5D15) matches. There are 3 types I know of - cable only (like a BX), cable and electric (seemingly the most common..fitted to all the Xantias in my local scrappies) and an electric only as was fitted to my 94 VSX.

By the way, be prepared for the oil leak when you remove it...
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SimonT
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Post by SimonT »

I'm thinking, after reading all this, that because the odometer still works spot on that it's a fault within the speedo itself yeah?
Anyone agree?
Saxo 1.5 XD 1998
(previously owned Xantia 1.9 TD sx 1995)
philhoward

Post by philhoward »

yep....the sender is OK
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Post by Xaccers »

philhoward wrote:When the speed sensor went on my Xantia, it would read fine below 50mph, then go absolutely bonkers (0-130mph); drop the speed and it behaved again. Finally gave up a couple hundred miles later...and the odometer stopped (that's probably the clue to sensor or clock)
I had a similar problem with my previous 95 SX until I heard a scraping noise along the motorway one day and the bottom cover of the engine bay dropped off.
From then until when my "lovely" neighbours torched the car the speedo behaved itself!
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