Scotland North AR Posted June 26, 2019 Share Posted June 26, 2019 Hi just returned from a hot run to Dinant in Belgium, highly recommended if you haven’t been.2009 Sigma 150 SV.After two days in the heat, sat nav stopped working as did the Speedo. On return to the UK in the cool, thespeedocame back to life asdid the satnav. The Speedo needle has always wandered about a bit and hasn’t had the revised earth mod done.I’m assuming that when fitted a new speed sensor a few years ago, I didn’t get the gap quite right. The heat of the last few days has made the gap grow ever larger and therefor the readings become progressively more erratic.what I also noticed today was the the trip is under reading by 6 miles in 30 miles when compared with the sat nav distance to a point on a route.Presumably the speed sensor works or it’s broken, nowhere in between?given that I’m getting some readings, all I need to do is correct the gap?What should the gap be?to test the unit, presumably wire it up to a battery and check the pulses equate to the high points on the hub? Any other ways to test it?Anyone else had to deal with this inaccuracy? Link to comment Share on other sites More sharing options...
Scotland North AR Posted June 27, 2019 Author Share Posted June 27, 2019 Found this excellent link on the club site https://www.lotus7.club/guides/technical-guides/speedometers Link to comment Share on other sites More sharing options...
Nillbymouth Posted June 27, 2019 Share Posted June 27, 2019 Hi Nigel,Interesting, I've had problems with heat. My speedo is accurate and I've never had problems until the hottest days of last summer when after a few miles it would bounce around for a few minutes then just stop reading. It has worked perfectly since so I'm putting it down to the heat. I've ordered the extra ground as detailed in your link above but have not got round to fitting it yet as hot days are not normally an issue in Scotland! Link to comment Share on other sites More sharing options...
Scotland North AR Posted June 27, 2019 Author Share Posted June 27, 2019 I’ve just followed the procedure for setting the sensor and found that the LED stayed on for ten of the 43 teeth i.e. the sensor was too close to the drive shaft. Had to adjust it a couple of times to make sure it counted all 43 teeth on the drive shaft. Have yet to try it on the road but it should be better.depending on result, I’ll fit the earth mod. Link to comment Share on other sites More sharing options...
Scotland North AR Posted June 27, 2019 Author Share Posted June 27, 2019 Speedo now rock solid, slightly over reading compared to sat nav. Trip similarly slightly over reading when compared to sat nav/My Route App. 27 miles on trip, 26.5 miles on sat nav and My Route App. Result! Link to comment Share on other sites More sharing options...
John Vine Posted June 27, 2019 Share Posted June 27, 2019 Pleased to hear the guide proved useful!JV Link to comment Share on other sites More sharing options...
Scotland North AR Posted June 27, 2019 Author Share Posted June 27, 2019 Excellent guide, thanks very much for doing it.The website search facility doesn't do too good a job of finding it though. Link to comment Share on other sites More sharing options...
John Vine Posted June 28, 2019 Share Posted June 28, 2019 If you're looking for greater accuracy, simply calculate and store a modified pulse code. Following the guide, display the existing six-digit code, multiply it by 27/26.5 (increasing the pulses/mile), and store this new value as a six-digit code with a leading zero. Then, if you want, you can fine-tune the code in the same way for even greater accuracy.JV Link to comment Share on other sites More sharing options...
Scotland North AR Posted June 28, 2019 Author Share Posted June 28, 2019 Many thanks John. I wish the speed sensor came with a set up/check procedure....maybe it did but don’t remember it. Link to comment Share on other sites More sharing options...
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