Martin J Posted March 25, 2015 Share Posted March 25, 2015 On Sunday's blat I noticed my speedo was flicking about a bit & then it stopped working. Back home & found the wire had come out of the end of the sensor. It does look pretty delicate & it is nearly 8 years old now. So £65 later & caterham have sent me a new one. Fitted it this evening, plugs together snugly & senor possitioned about 1mm from the toothed ring & it it still doesn't work. Does anyone have any ideas please? Possible a duff sensor, I will ring CC tomorrow. How does it work? I assume it's optical but appears to have a rubber end to it. No visible light but perhaps it's infra red? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 25, 2015 Member Share Posted March 25, 2015 Is this the electric sort on the gearbox or on a driveshaft?Have you checked the relevant fuse?Jonathan Link to comment Share on other sites More sharing options...
Martin J Posted March 25, 2015 Author Share Posted March 25, 2015 All electric on the Sigma, Jonathan. Sensor on the rear offside wheel.Pulled the 7.5 amp instrument fuse & all the dials stop. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 25, 2015 Member Share Posted March 25, 2015 Only used magnetic ones on bikes!Does look relevant to that type? It could be modified to work at both ends of the cable to the speedometer.Jonathan Link to comment Share on other sites More sharing options...
Martin J Posted March 25, 2015 Author Share Posted March 25, 2015 You could be right in that it works on hall effect & is therefore magnetic rather than optical. Although the wheel it aligns with looks plastic to me but perhaps has some metal in it somewhere?Where is Mick Attree when you need him? Link to comment Share on other sites More sharing options...
mic Posted March 25, 2015 Share Posted March 25, 2015 YHM Link to comment Share on other sites More sharing options...
Martin J Posted March 25, 2015 Author Share Posted March 25, 2015 Thanks Mic. Link to comment Share on other sites More sharing options...
makingff Posted March 25, 2015 Share Posted March 25, 2015 Have you done the earth mod? Link to comment Share on other sites More sharing options...
SM25T Posted March 25, 2015 Share Posted March 25, 2015 Mike Clark had this ..... cable chafed through on cable tie to chassis near rear wheel. Link to comment Share on other sites More sharing options...
michaeljclark Posted March 26, 2015 Share Posted March 26, 2015 Yep, suffered this on the IOM.Martin, the sender will (if CC haven't changed it) light up (at the back where the cable exits) as the teeth on the ring pass past, my new one seemed to be quite relaxed on the position (ie it worked with up to 4mm gap)I'm on call this weekend and am picking up the new Motor on Saturday, but if you want to come past on Sunday, we can take the sensor off mine and test if you like? I'm also 1/2 days most of next week, so can do then too. I had a tidying session in the "Mancave" aka Garage up, so we can work in releatve comfort with both 7's under cover!!Mike Link to comment Share on other sites More sharing options...
Martin J Posted March 26, 2015 Author Share Posted March 26, 2015 Thanks for the offer of help Mike, will let you know. I felt the replacement was rather expensive for what it is but no choice as the old one had fallen apart.i would like to see your new car & posh garage mate. Mick has given me a couple of things to look at.i thought I was down to fit you a Hive but don't know what happened there? Link to comment Share on other sites More sharing options...
michaeljclark Posted March 26, 2015 Share Posted March 26, 2015 I thought your fellow engineer was going get you to give me a call. When I've sorted some bits out in the next few weeks, I'll give you a shout!Mike Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 26, 2015 Member Share Posted March 26, 2015 What's the earth mod, please?Jonathan Link to comment Share on other sites More sharing options...
Leadership Team Garry7 Posted March 26, 2015 Leadership Team Share Posted March 26, 2015 Jonathan, it's a CC Workshop mod. I can send it over later if you like, have it on PDF.it basically adds an earth at the rear of the car before the sensor plug. My continually flickering speedo has not messed about since the mod.Martin, move the sensor gradually away from the toothed wheel - mine is at least 2mm - failed to work at first like yours, gradually moved it further out until it started working. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 26, 2015 Member Share Posted March 26, 2015 Thanks. I'll remember that when I finally assemble my list of documents for the site. Or is it here already?Jonathan Link to comment Share on other sites More sharing options...
Martin J Posted March 26, 2015 Author Share Posted March 26, 2015 SUCCESS. My thanks to Mick Attree for advice over the phone & some tips from people here on blat chat.i brought the gap out to about 4mm & it worked fine. At this stage it doesn't appear to need the extra earth & it worked fine without it for nearly 8 years up until the point the wire broke.i am intrigued as to how the light beam works with a rubber bung on the end? As Mike says you can see it flashing around where the cable joins the sensor Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 26, 2015 Member Share Posted March 26, 2015 Glad it's working.Is the light a self-powered indicator for testing purposes or something else?ThanksJonathan Link to comment Share on other sites More sharing options...
Dr Slotter Posted March 26, 2015 Share Posted March 26, 2015 It is a Hall effect sensor and the light indicates when it is outputting a voltage. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 26, 2015 Member Share Posted March 26, 2015 ThanksJonathan Link to comment Share on other sites More sharing options...
makingff Posted June 24, 2015 Share Posted June 24, 2015 Hi MartinJust wanted to check how you tested the sensor as I was being completely dim last night when I fitted a new one to my car - it's not working. I'm not going to explain how I was trying to test it as it's too stupid. Having thought about it since, I reckon that as long as the ignition is on, I can 'wave' the sensor near the cogs (rather than have them turning in front of the sensor) and I should at least see the light at some point? This will prove that it's working.Then, having fitted the sensor (it's a very tight fit with the caliper...), just turning the hub should trigger a signal and, therefore, the light once it's in the correct position. Correct?Simon Link to comment Share on other sites More sharing options...
SM25T Posted June 24, 2015 Share Posted June 24, 2015 Martin is away in the 7 overseas without Internet. Link to comment Share on other sites More sharing options...
makingff Posted June 24, 2015 Share Posted June 24, 2015 Cheers Ian Link to comment Share on other sites More sharing options...
Leadership Team Garry7 Posted June 26, 2015 Leadership Team Share Posted June 26, 2015 Hi Simon,That should be it. Mines more than the recommended 2mm away from the cogs having been moved out gradually until it worked.Garry Link to comment Share on other sites More sharing options...
makingff Posted June 27, 2015 Share Posted June 27, 2015 I got mine working last night.I ended up making a small bracket to move the sensor away from the calliper as it was a very tight fit! I also covered the wires in cable shrink stuff to hopefully remove the chance of any chaffing.2mm worked for me too. Link to comment Share on other sites More sharing options...
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