AndrewBClarke Posted March 26, 2017 Share Posted March 26, 2017 Quickie - driving home yesterday my VDO speedo suddenly went from 30mph (rare slow speed) to 140mph or top of the scale. Is it likely to be the speedo itself that needs changing or a wiring issue? It might be if no relation but the milometer LED readout takes a while before it displays anything and even then is unreliable even though it keeps the reading correct. Andrew Quote Link to comment Share on other sites More sharing options...
Mighty Mart Posted March 26, 2017 Share Posted March 26, 2017 Sounds to me as though you have a speedo cable issue? Have you got a right angled speedo drive? I haven't, and the cable has to bend too tightly in the tunnel without one. A new cable works ok for a short while, and then exhibits the symptoms you are describing. Mart. Quote Link to comment Share on other sites More sharing options...
AndrewBClarke Posted March 26, 2017 Author Share Posted March 26, 2017 Mhmm. No idea. Will have to look. I know it has a sender on the rear prop shaft so assumed it was electronic so no speedo cable as such. Checked and no speedo cable. All electronic using a sender. Thanks anyway! Quote Link to comment Share on other sites More sharing options...
fossett Posted March 26, 2017 Share Posted March 26, 2017 Hi, I've had this, i think its due to moisture build up during the 'off season'. Leave your side lights on at every opportunity and there heat from the bulbs will help to dry it out, failing that, a trick often recommended here is to try removing it, submerging it in rice (dry not wet) and putting it in your airing cupboard for a while. 1 Quote Link to comment Share on other sites More sharing options...
Mighty Mart Posted March 26, 2017 Share Posted March 26, 2017 Ah, ok. If electronic, definitely not a cable issue.... hope you get it sorted ok...looks as though you've been oriented in the right direction despite me throwing you a curve ball initially lol... Mart. 1 Quote Link to comment Share on other sites More sharing options...
AndrewBClarke Posted March 26, 2017 Author Share Posted March 26, 2017 On the positive, 0 to 60 is better - now about 1 second! Top speed of 140 mph in 3 seconds from a standing start is also not bad! Quote Link to comment Share on other sites More sharing options...
Julie Hall - WSCC AO Representative Posted March 26, 2017 Share Posted March 26, 2017 I had a similar issue a couple of weeks ago, Andrew. I was merrily driving along and my speedo suddenly showed a very low speed, and then went down to nought. It sorted itself out and just returned to normal after a stop and a restart. My LED reading is very hit and miss all winter too, that's kit cars for you. So now you have an excuse to pop out tomorrow and see if it is still the same. 1 Quote Link to comment Share on other sites More sharing options...
Dave-P-H Posted March 27, 2017 Share Posted March 27, 2017 My speedo did the exact same thing at the weekend. Usually the digital display disappears over the winter but it's the first time the speedo has done this. Got home, left it parked on the drive for half hour, went back out and it was working OK, 1 Quote Link to comment Share on other sites More sharing options...
Ray The Brake Posted March 27, 2017 Share Posted March 27, 2017 Looks like a VDO trait my speedo would show digital read out intermittently, outside temperatures have risen over the last couple of days problem has gone. " Moisture" no evidence to prove either way so I'm puzzled Quote Link to comment Share on other sites More sharing options...
Welly Jen Posted March 27, 2017 Share Posted March 27, 2017 A poor earth connection to the speedo can also cause these sorts of effects. Jen Quote Link to comment Share on other sites More sharing options...
AndrewBClarke Posted March 27, 2017 Author Share Posted March 27, 2017 According to an aironautic engineer, a poor earth connection would cause the reading to go down to zero as a circuit would be broken. If the needle or reading goes up it is either a faulty gauge, sender or moisture. I am going with the moisture problem to start with as it is the easiest (and cheapest) to resolve. I have used the car all winter so no idea why it should happen now. Not bothered about the mileometer but thought it might help with diagnosis. Roll on the warmer weather and we will see what happens! Quote Link to comment Share on other sites More sharing options...
TAFKARM Posted March 27, 2017 Share Posted March 27, 2017 Echo the airing cupboard fix, the VDO speedos dont seem to like this weather. 1 Quote Link to comment Share on other sites More sharing options...
AndrewBClarke Posted March 27, 2017 Author Share Posted March 27, 2017 Russ. The photo of your engine looked a bit more problematic than my speedo. What's up? Quote Link to comment Share on other sites More sharing options...
TAFKARM Posted March 27, 2017 Share Posted March 27, 2017 Not sure, so I'm putting it in the airing cupboard overnight to see if that helps! Quote Link to comment Share on other sites More sharing options...
Beez Posted March 27, 2017 Share Posted March 27, 2017 I had the same issue with the Megabusa, the problem was the prop-shaft had hit the sensor due to the prop-shaft flange bolts being loose and allowing the prop to vibrate. The prop was actually MISSING a couple of bolts and the rest were just finger tight, I had only just picked it up from the old owner and thought he was obviously an idiot to let them get so loose!!! Though to be fair I seem to have to tighten them up after every sprint/track day as the bike engine and Westfield reverse box seems to vibrate them loose, even with loctite and locknuts, the metal not nylon version, fitted!!! Quote Link to comment Share on other sites More sharing options...
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