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        General >> Problems >> Speedo going on and off
        
(Message started by: tlundkvi on May 19^th, 2009, 5:43pm)

Title: Speedo going on and off
Post by tlundkvi on May 19^th, 2009, 5:43pm

Hi all,

Starting from this afternoon, I lose my speedo. Sometimes after starting it works, and goes off after a while for the rest of the trip. Other times when not working at start, I get loads of other interesting behaviour, like won't shift gear up and power steering becomes very stiff. Checked the diagnostics mode (in-dash), and it shows '00'. Leaving the car for a while to rest, makes the likeliness of speedo working at start higher.

I suspect a loose wire, but have no idea where the speed sensor is located, let alone how the wires are routed. A replacement sensor is probably not a bad idea either to have just in case, even if it turns out to be a broken wire (24V 1995, offers welcome to PM).

The rear right bearing will be replaced on Thursday, is the sensor around there and possible excess heat causes this?

All other meters work nicely (rpm, coolant etc.)

Thanks in advance, all help is welcome!

Title: Re: Speedo going on and off
Post by Snoopy on May 19^th, 2009, 6:30pm

Its the VSS which is fitted to the side of the gearbox is the most likely cause . It may be just a broken wire but they are known to fail. It is mentioned in HERE (http://www.fordscorpio.co.uk/eecv.htm)

Title: Re: Speedo going on and off
Post by tlundkvi on May 19^th, 2009, 6:39pm

Thanks! Will check it out on Thursday.

Title: Re: Speedo going on and off
Post by Jonnycab on May 20^th, 2009, 12:37am

Just another possibility, although I'm sure Snoopy is most likely correct ;)....

You say the power steering becomes very stiff as well & I'm not sure a dodgy VSS will cause this. It could be a completely separate problem, but it's worth checking that the small black lead on the battery negative is on nice & tight. If it's even a tad loose then it can cause all kinds of problems :)

Title: Re: Speedo going on and off
Post by Highlander on May 20^th, 2009, 12:42am

24v has the speed sensitive rack Jonny, it uses the VSS value

Title: Re: Speedo going on and off
Post by Jonnycab on May 20^th, 2009, 12:47am

Oh yea :-[...forgot about that ::)...sorry :)

Title: Re: Speedo going on and off
Post by Highlander on May 20^th, 2009, 12:50am

Let you off.... just this once ;)

Title: Re: Speedo going on and off
Post by Jonnycab on May 20^th, 2009, 1:03am

:-*

Title: Re: Speedo going on and off
Post by Snoopy on May 20^th, 2009, 6:34am

Well worth reading VSS (http://www.fordscorpio.co.uk/manual/electrical/intbasic/VSS.pdf) give details of how to remove

Title: Re: Speedo going on and off
Post by tlundkvi on May 20^th, 2009, 7:33am

Thank you for helping me out, nice to know it's not as complicated to change, to have a bottle of ATF ready for the job is valuable info. Now it would probably be a good idea to consider ATF change too... First I'll check the leads though.

Title: Re: Speedo going on and off
Post by Snoopy on May 20^th, 2009, 2:48pm

The amount of ATF loss is really minimal no need for fluid change at the same time .

Title: Re: Speedo going on and off
Post by tlundkvi on May 28^th, 2009, 1:37pm

I am more and more convinced, after checking wires and the behaviour of the speed sensor, this is not a loose wire. The speedo works almost always when it has cooled down a bit. After aprox. 6-7 minutes of driving, it stops giving a reason. Very seldom it goes on again during the drive, but then again my trips are 10-30 minutes at most right now.

There has never been any form of quickly on, off again, on again pattern.

Is this failure model at all familiar? What could cause this? A brand new sensor is on it's way anyway.

Title: Re: Speedo going on and off
Post by Snoopy on May 29^th, 2009, 7:34am

Erratic behavior of the speedo and associated parts IS vindictive of a failing VSS from MY experience... Mine car and speedo etc was behaving very strangely for a couple of weeks and ALL was cured when I replaced it.

Title: Re: Speedo going on and off
Post by tlundkvi on May 29^th, 2009, 7:47am

Thanks, as I've just ordered the almost 100 euro part (Finis 1021991, tech. 95GB-9E731-DA), I was worried of that the pattern of functionality would indicate other weird errors.