Speedo

[Mukes]

Hello - I am a mechanical Numpty and need your help. The Speedo on my Chimaera mostly does not work and then occasionally surprises me by working fine for a period of time. Please can you point me in the right direction using mechanical words of single syllables.



>>> Edited by Mukes on Thursday 10th March 15:55

[stuartL]

Technically it's called 'buggered' ! Sorry thats 2 sylabubbles :/

[parrot of doom]

Get yourself a copy of Steve Heaths book on Griffs and Chims, it tells you in detail how to remove the dash/fascia etc

[spend]

Speedos & speed sensors changed over time, there are several different types fitted. Without any details of your car, its hard to offer any specific advice.

ie, year of manufacture, gearbox type, diff type..

HTH, Dave

[V8 Archie]

I can't remember the technical name for the gubbins that I'm thinking of, but its the bit attached to the diff that generates the pulses that are sent to the head unit. It consists of a plate across which a cog rotates (each tooth contact genearting a pulse). This is a known weak point and may have worn out. It's not expensive.

Please note that the above is a mixture of badly remembered stuff that I was told by someone else and a bit of supposition/guesswork on my part.

[SwanJack]

I had this a few months back. The speedo would work when cold and would pack in when warm. Then gave up completely. If your odometer works and the speedo doen't then its the speedo. If they both don't work then its the speed sensor/transducer on the diff and is the most common problem of the two. You may get away with resetting the gap between the cog on the diff and the transducer. I paid £63 for the transducer and £40 to fit.

[travelsveryrapid]

I had the same problem, it stooped working altogether eventually and it turned out to be the speed sensor. Apparently if it's an early Chim the part is hard to get but I got mine from David Gerald who had them in stock and got it fitted by Dreadnought who do my servicing.

Good luck,

Steve.

[Mukes]

Thanks all for your responses. Most helpful. I have a 1997 4.5 all standard spec. if this casts any more light on the problem?

[spend]

Sounds like you have 3 major components, sensor above the output flange of the diff (gap seems to be reasonably critical on these), an electronic box in the dash which splits the signal between the ecu & speedo (heat & electric boxes!), and of course the speedo itself. I'm sure somebody with more experience of this particular set up will give you more info, not sure how mucj you can do yourself apart from check gaps & condition of wiring.

Dave