Speedo - is this a problem?

Harry · Post by **Harry** » Tue Jul 18, 2006 12:15 am

Tootling along today at a fairly leisurly pace whith her who must not be named sitting alongside and the speedo suddenly flicked from 50mph to zero and then back to 50.

Surprised exclamation from me (to put it politely)...her nextdoor says...'yes it's always doing that, I thought it was normal'

So...is it???

H

moonshine · Post by **moonshine** » Tue Jul 18, 2006 7:17 am

Most definitely not! Speedos do not do this without reason. I would think that the most likely cause was a dodgy connection somewhere, like the speed sensor or possibly the converter chip, if yours has one.

waycar8 · Post by **waycar8** » Tue Jul 18, 2006 5:23 pm

i had this happen on my focus harry..........it was the speed sensor.

hows the rad cement holding up?

Peg leg Pete · Post by **Peg leg Pete** » Tue Jul 18, 2006 9:09 pm

Our speedo does it usually when setting off at traffic lights, spins right round the clock, I think it is getting too excited at the thought of beating a Citreon Saxo off the mark

madmile · Post by **madmile** » Tue Jul 18, 2006 10:11 pm

I have had a similar problem with a vehicle with speedo chip fitted. What seemed to trigger the problem was either air con, radio or mirrors being fiddled with. Rev counter would momentarily blip maybe even km move on by a 10th or 2 and hold light start flashing.
Waiting for customer to come back off holiday in the van to see if removing the chip stops the problem. Hoping it does as I drove 200 miles the week before handover with no problems.
Apparently there were a batch of faulty chips around 6 months or so back.
Peter / Harry, are yours chipped?

Harry · Post by **Harry** » Tue Jul 18, 2006 10:37 pm

Havn't the foggiest if my bongo's chipped..but I did get rid of the curry smell this evening...see 'radiators'.

madmile · Post by **madmile** » Tue Jul 18, 2006 11:14 pm

If its 'chipped' you will have the original dial - probably the 'k' on kph blacked out. Effectively a 180mph speedo.
If not, you will have a repacement dial with mph and kph, but the odometer will click round in km.

Harry · Post by **Harry** » Tue Jul 18, 2006 11:16 pm

Mine's not chipped then.

H

Peg leg Pete · Post by **Peg leg Pete** » Tue Jul 18, 2006 11:33 pm

Not chipped I think, but performance is not affected by the twitchy needle!

Bonza · Post by **Bonza** » Wed Jul 19, 2006 9:19 am

madmile-
If you're right about the faulty chip that would explain my problem. Bongo bought about 4 months ago from dealer

Just done 200 miles, lots of stops-no problems.
Previous outing about 5 times, start up -no speedo, then hold flashing. Restart, problem gone.

Its so intermittent I can't reproduce it on demand. Will get dealer to fit a new chip on the first service. Dont believe its the speed sensor as it goes long periods without a problem.
Bonz

Veg_Ian · Post by **Veg_Ian** » Wed Jul 19, 2006 9:31 am

As a matter of interest, does anyone know if the chip is readily available and an approximate cost?

mick · Post by **mick** » Wed Jul 19, 2006 9:52 am

Veg_Ian wrote:As a matter of interest, does anyone know if the chip is readily available and an approximate cost?

The chip is available quite easily. Here is one on ebay ?40 ? ish ?

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0004795261

But worth checking the connections on the back of the speedo first. Mine showed the same symptoms, and I fixed it by simply tightening the screws that hold down the chip wires on the printed circuit board.

Peg leg Pete · Post by **Peg leg Pete** » Wed Jul 19, 2006 10:15 pm

Mick could you please tell how you get to the back of the speedo, want to check wire connections

mick · Post by **mick** » Thu Jul 20, 2006 1:06 am

Hi Pete. Here is a copy of a previous posting (now locked)

Hi Stu

If it is a wiring fault at the back of the speedo, this is what you need to do :-

Undo the various phillips screws that hold the black plastic fascia (I think there are 2 screws recessed at the top, and 2 just under the dash area. Slacken the clamp to lower the steering column as far as it will go. Undo the remaining screws which hold the speedo/ revcounter console to the dash, and wriggle it free as far as you can. Then disconnect the wiring connectors at the back (there are 2 connectors and they are fiddly). You should then be able to completely remove the unit.

Then check that all the wiring, and screws are tight ( and no short circuits), and put it all back together. I've made it sound complicated, but in all honesty I'm no mechanic and it took me about 40 minutes or so. The problem never came back !

Don't forget to do up the steering column when you have finished. Imagine anyone forgetting that

2sticks · Post by **2sticks** » Thu Jul 20, 2006 3:50 am

Bonza,

Don't waste your money on a new speed converter.
This is a simple frequency converter and will almost
certainly not have an intermittent fault, either
it works or it doesn't work, you could probably
make one for about 50p and a soldering iron.

The input signal is quite a low voltage square
wave and as Mick says it's imperative that all
the connections are secure and tight.

One of the fault codes that flashes the hold
light is that the ECU is not receiving the
same speed signal via the speedo head, so that
seems to be working correctly.

The ECU doesn't monitor the speed signal below
about 10 MPH so the hold light will not flash for
this fault until you reach this road speed.