James Quigley Posted November 11, 2007 Report Share Posted November 11, 2007 My speedometer on my car is jumping around like a tit. (rangeing from 20 - 100mph).It only happens when I accelerate, when I ease off the accerlerater it reads the correct speed steadily, but then accelerating again it just jumps around loads.Any Ideas what could be causing it? (I'm not mechanically minded at all) although I'm guessing at a dodgy sensor or other electrical fault Quote Link to comment Share on other sites More sharing options...
Monkman Posted November 11, 2007 Report Share Posted November 11, 2007 What car do you have? Quote Link to comment Share on other sites More sharing options...
James Quigley Posted November 11, 2007 Author Report Share Posted November 11, 2007 1997 Renault Megan Scenic Quote Link to comment Share on other sites More sharing options...
ManxTrialSpaz Posted November 11, 2007 Report Share Posted November 11, 2007 (edited) 1997 Renault Megan ScenicThere's your problem Isn't the speedo read off the wheels? SOunds like loose wiring/bad connection somewhere down the line. Getting interefence from everything else happening when you put the pedal down (spark plugs and that kinda stuff)? Edited November 11, 2007 by ManxTrialSpaz Quote Link to comment Share on other sites More sharing options...
Wet Banana Posted November 11, 2007 Report Share Posted November 11, 2007 I started to write quite a comprehensive reply, but I deleted it all. In short, I don't know.Not knowing much about Megans, or Renaults for that fact, I'm guessing the speed will be read off the final drive in the gearbox somewhere, I'm also guessing that it won't be read by cable, so the fault would definately be electrical. Possibly a loose connection, interference (most unlikely) or just a buggered speedo unit.Next time you pass a dealership, ask a mechanic there, but don't get them to "look" at it. That will cost. Quote Link to comment Share on other sites More sharing options...
Bucky Posted November 11, 2007 Report Share Posted November 11, 2007 more than likly gets its reading from the ABS sensors but could be a sensor on the G/box.try a renault forum.or go to a renault dealership and see a member of parts staff, ask them if they have sold a lot of G/box speedo sensors, if they have then its probably a comon problem and might fix it.or take it to a 'Fred ina Shed' styleee garage and get them to have a look. Quote Link to comment Share on other sites More sharing options...
Monkman Posted November 12, 2007 Report Share Posted November 12, 2007 Speedo readings or off the abs rings on the front wheels (both) take it to a garage with diagnostic tools and they will plug it in and should be able to tell you which sensor is faulty. that or your abs rings might have cracked but your lights on you dash will of lit up if that was the case i think. Quote Link to comment Share on other sites More sharing options...
Joe Sheehan! Posted November 12, 2007 Report Share Posted November 12, 2007 My speedometer on my car is jumping around like a tit. (rangeing from 20 - 100mph).It only happens when I accelerate, when I ease off the accerlerater it reads the correct speed steadily, but then accelerating again it just jumps around loads.Any Ideas what could be causing it? (I'm not mechanically minded at all) although I'm guessing at a dodgy sensor or other electrical faultWell obviously! Thats what a speedo is supposed to do!!Nahh, sounds like a sensor is misreading, but i dont know where the sensors are so thats as far as i can help. Quote Link to comment Share on other sites More sharing options...
Walleee Posted November 12, 2007 Report Share Posted November 12, 2007 can't help but my mate has the same car and his does exactley the same thing. he tells people he can do 20-80 in the blink of an eye. Quote Link to comment Share on other sites More sharing options...
Will Arnold Posted November 12, 2007 Report Share Posted November 12, 2007 this is exactly the reason i like old cars, they have little electrical systems!it could be a wide range of things, but my guess is that its a loose earth. Quote Link to comment Share on other sites More sharing options...
James Quigley Posted November 12, 2007 Author Report Share Posted November 12, 2007 can't help but my mate has the same car and his does exactley the same thing. he tells people he can do 20-80 in the blink of an eye.20-80 pah, I done 0 - 120 - 0 in under 2 seconds. (and the handbrake was on and I was out of gear). Quote Link to comment Share on other sites More sharing options...
trials_pimp Posted November 12, 2007 Report Share Posted November 12, 2007 Dont know much about french shit, but there are 2 similar problems that Fords Have that do the same thing.Escort - MK5-6Speedo jumps and wavers about - Cause is the Differential Bearings being worn and causing the Speedo cable to miss parts of the final drive where it takes the reading.Focus - 99 - 04Speedo drops of, revs drop, cuts outCause VSS goes open circuit and doesnt read properly. The VSS reads from the Diff again, but is electrical.Find out where your speedo reads from and how. Quote Link to comment Share on other sites More sharing options...
Radfax Posted November 13, 2007 Report Share Posted November 13, 2007 Speedo readings or off the abs rings on the front wheels (both) take it to a garage with diagnostic tools and they will plug it in and should be able to tell you which sensor is faulty. that or your abs rings might have cracked but your lights on you dash will of lit up if that was the case i think.just got qualified to use the snap on diagnostic computers at collage and this is your best bet! Take it to a renult garage, get them to connect it up but also ask for a print out of the fault codes so that you can see they have replaced only what is needed! i would say bring it to me and i do it for you but seen as you are from the island of white and im from kent i cant see it hapening! Quote Link to comment Share on other sites More sharing options...
James Quigley Posted November 13, 2007 Author Report Share Posted November 13, 2007 I'm hesitant about taking it to a renault garage as I don't want to be F'd in the A, cost wise. Quote Link to comment Share on other sites More sharing options...
Monkman Posted November 13, 2007 Report Share Posted November 13, 2007 Renault will charge you £90 for a diagnostics check but if there's a fault it WILL show, if they do the work to fix it usually the charge will disappear. id look through your yellow pages theres back street garages that specializes in diagnostics think it will be under auto electrics?! prob cost about £30 Quote Link to comment Share on other sites More sharing options...
Radfax Posted November 13, 2007 Report Share Posted November 13, 2007 They may not charge £90, dependant on what kit they use and how nice they feel they can charge between £45 to £90, BUT if they use this they will pick up the problem. If they dont they will charge you hours of labour which is rated now at around £120 per hour (approx) so to be honest you will be better of paying a diagnostics fee, with this you can ask for a print out of the fault codes and see if they have charged you for the right parts ect! If you take it to a renault dealer and they hook it all up and tell you this that and the other is wrong with it ask for a print out of the graphs and fault codes, give me a call and i will tell you if they are talking out of thier arses or not! I would strongly advise you NOT to take it to a back street garage, 90% of them are cowboys! I cannot suggest more to stay away from them! Quote Link to comment Share on other sites More sharing options...
James Quigley Posted November 14, 2007 Author Report Share Posted November 14, 2007 The missus works in a honda/mazda dealers and is good mates with one of the mechanics, so shes persuaded him to take a look at it for free, I dread to think how she persuaded him. Quote Link to comment Share on other sites More sharing options...
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