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MG MGF Technical - Speedo unsteady and clicks at 25 -30mph

Hi All,

Happy New Year for 2007.

I have an 98 MGF VVC. It has a problem whereby the speedo pointer starts to becomes unsteady as you approach 25mph and gets worse to 33mph before becoming steady again. When it does this you can also hear a clicking noise which goes as it becomes steady.

Anybody had a similar problem and know how to fix it - likely cost - it's annoying but also means I cannot guage my speed around the important 30mph mark.

Thanks in advance.

Richard
R Hunt

It's a fairly common fault.

Mine has always bounced a bit in the 25-30 range

Almost certainly one of the joints in the speedo cable (there are 3 including where it connects into the speedo itself), or the route the cable takes may have a sharp bend in it

Try unplugging and replugging each section. Give them each a twist see if they rotate freely.

If my memory serves me correctly you'll find one joint under the bonnet and another on the underside of the car at the rear of the mid section following the line of the coolant pipes

If you can here clicking it may even be loose behind the speedo so thats another point to check

Stu

Stu Dickens

I totally agree with Stu - mines done that since new from 1998 but have learnt to live with it :)

Steve
Steve P

I tip I picked up on here is to put some copperslip grease in the cable in first join from the speedo when you disconnect the two pull the cable about an inch out and coat it.
Jon Baker

Mine does it too!

Fiona :-()
Fiona

Same here on my 1998 at around 25-35 mph. Never bothered me, although I don't getting the 'clicking' sound you describe. Bit of info on ther subject care of Rob Bell:

http://mgf.ultimatemg.com/group2/DIY/Speedo_cable/index.htm

Emma Jackman (& Green with Envy ~ S369 FAR)
Emma Jackman

Hi!

An alternative safety feature is to mount a safety
camera detector on your dashboard. Available from
Halfords/Tesco's and many other places from about
£70 upwards, might even be cheaper. Most GPS units
give a constant MPH readout which I believe is
pretty accurate on the speed you are actually travelling at. The cost of speeding tickets due to
an unreliable speedo might be offset by such an
investment. Some sat/navs.also incorporate this
feature.

Regards - Bill
W.A. Pearson

Hi Richard

Ditto to the above had the same problem, checked joints and used grease...
ended up buying one of the GPS speed units as bill suggested found that the speedo was out as well ??
cheaper than a ticket..

Markj
MA Jenkins

Agree with posts about flickering. Speedo on my car is well out to but as it is optimistic there not too much worry of getting a speeding ticket!
Also since fitting 16 inch TF wheels it over reads even more as the effective diameter and hence overall gearing must have been reduced.
Dave

>>>>>>Also since fitting 16 inch TF wheels it over reads even more as the effective diameter and hence overall gearing must have been reduced.<<<<<<<

As I understand it, by fitting 16" wheel (and presumably lower profile tyres), the overall rolling diameter will remain about the same thus cancelling out any difference.
Steve P

Steve, I thought that 2 but according to my Sat Nav my speedo is now around 8-10mph over at 70mph. Wheels are standard TF 16" multispokes with Goodyear F1's on a 1996 1.8i
Dave

Most cars are 10% over - that is what they are allowed by official agreement - so if you are doing a steady 70 on your speedo you are probably only doing an actual 65 ish - that way you avoid being done for speeding.

And remember that most sat navs give you a speed reading according to map distance covered and may not make allowance for extra distance going up and down hills, not a problem here in the UK but could make a difference in a hilly country.

And Steve is correct regarding the lower profile on larger diameter wheels for the F/TF so that the rolling distance is the same.
Ted Newman

Dave,

Have the front tyres been changed from the standard 185s ?
Jon Baker

I believe the fronts are 195 and the rears 215 which are the standard TF sizes. Before I fitted 16 inch wheels I was running 195's on my 15" wheels at the front.
Dave

I agree with everyone's estimate of 10% over-reading - I reckon mine's the same. The original Autocar road test was 10% all the way up the speed range. It means that if you factor in the ACPO margin of +10% + 2mph on true speed before the cops get too excited, you could theoretically be showing 70mph limit +7 (10%) +2 = 79 + 7.9 (10% speedo error) = 86.9 on the clock past the mobile speed camera and they might not blink.
Anyway, why in 2007 can't cars be made with accurate speedometers? Then there'd be no doubts or arguments (but it would look less exciting!)
M Cunningham 1

This thread was discussed between 04/01/2007 and 09/01/2007

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