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Discussion Starter #1
Hi there

My speedometer goes crazy.
At any small increase in speed it jumps up to twice or three times the actual speed, and then drops to sort of the correct speed.
At the same time the trip-counter ( km / milage counter ) is also rapidly climbing: so my car went 27 km older in a 1 km stretch ( gonna be expensive when I sell it on!!!)

I did already see this thread and this thread.

If it is down to only cleaning the contacts either on the backside of the dial or the plugs in the footwell I can manage that. But if it is the plug for the sensor or the sensor itself it is going to the repair shop.

I was hoping one of the honorable experts in the forum could quickly judge where the error most likely is.
Especially since the other threads didn't describe the counter-issue.

thanx in advance.
 

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Discussion Starter #2
Okay so now this morning she was behaving much better, with only an occasional flicker on the speedo. Maybe the problem was caused by the last few days of heavy rain and humid air, or me wearing extra pointy shoes and unconsciously 'messing' in the wire-loom under the steering wheel.

However what I really think did the trick, was that I showed my Bella some more respect. Yesterday night made shure that the batterypoles were sitting properly, and I took her for a proper spin to let her show the best that she can - a little high on the revs, a notch above the speed limits, sharp cornering etc (GTVs feels like they are really not meant to be driven slowly!).
And this morning I was showing her extra love by talking nicely to her " Bella ragazze, sei la piu bella machina del mondo" etc etc.... you know the drill. She behaved much nicer.
She probably felt a bit neglected for me not spending time on her even though I had a few days off before the weekend.


Anyway I think I am gonna have a try on the wiring loom in the footwell. I do know my electronics at home, but besides not tearing wires out of the plugs, is there anything I should be careful of? I am fearing something like: "If you undo these two plugs, the imobilizer/alarm/enginecontrol will stop working for good even if you put the plugs back together!"
Do I need to take off the poles on the battery? I am also a bit weary about this for the same reasons.
Your advices would be much appreciated.
 

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I had similar problem. Which was cured when I took out speedo pod to replace abs light bulb

The speedo (and rev counter) connects to circuit board with 4 pins that just slot into the board. I am assuming reseating speedo made better contacts?

Worth a try

Rich

PS my car had got very wet in the footwells (puddles) so it may have been condensation
 

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Discussion Starter #4
Thanks Rich

What an easy fix: Two screws out and the dials are out.

Did it yesterday night, and this mornings drive to work showed that it worked.
It did only one 'jump', but I guess I could pull it again and maybe give it some contact spray to clean the last bit of poor contact.

At least I am no longer fearing that something more serious is wrong, which is not that bad :)
 

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I think you're right about the attention seeking. I was having temperature dial problems. I'd replaced the thermostat, and it was still misbehaving, so I bought a new coolant temperature sensor. Took everything off in the engine bay that was in the way, and I couldn't get the old one off. It was getting late, so I put it all back together with the old part still fitted, and it works perfectly. (In Alfa Romeo terms anyway...). I obviously haven't been attentive enough. :confused: :lol:
 

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The early cars (like mine with the 5 speed box) can have issues with the speed sensor on the gearbox going mad. Mine would just stop working and then jump into life randomly - diagnosed as a faltering signal form the sensor on the box.

Unfortuantaly they are not available any more, so its a second hand part job. Mkae sure you get a part number off yours that matches though, they dont all fit.

Mark.
 

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Discussion Starter #8
hmmm not nice Mark. I still have problems and I am hoping it is not in the same league as yours.

The problem is definitely that the speedometer and the odometer are getting way too many pulses. It is worst after a 10 minutes drive, and these two things occurs:
1) when accelerating the needle goes to twice the speed then (usually) falls down to normal level.
2) braking and going below 40 km/h - the needle flickers wildly before going to zero.
Besides the odometer is clocking far too many km's. ( a 1km drive gets to 27km :eek: )

Now the reason for getting too many pulses could be down to a poor connection from the supply to the sensor, or from the sensor to the boardcomputer, making the signal disconnect and reconnect many times in a milisecond.

I undid the speedo/rev counter unit twice and cleaned the connectors, so apparently nothing is wrong there. ( they didn't look corroded anyway)
Could be the problem with the connector in the center console described here ...I tried to get to it today but didn't manage ( one can't get to one of the screws because of the speeder, and now it is raining.) I really hope it is just that.

IF it would be the sensor I found this (see the image) in the manual - but I cannot figure out where that is exactly. I tried too look through the top of the enigne - cannot recognize any of that in the image ( mine is a V6 turbo, so I guess it should look something like the top left image)

... Any clues ???
 

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Discussion Starter #9
For the reference: I couldn't fix it myself so I took it to the garage.
It was the tacho/speedo cable that were being rubbed against something and shortcircuitet.
 

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Discussion Starter #11
Very good John, but as you can read erlier in the thread I did already try this without luck.
 
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