RFF Posted July 7, 2016 Share Posted July 7, 2016 Following a successful rolling road session when new ECU ( MBE) unit was fitted, I noticed that the speedometer no longer worked.On initially turning on the ignition all the dials, including the speedo perform the full sweep function, but there is no MPG reading or mileage addition to the present display.I have replaced the sensing head, although there was no obvious problem with the previous unit ( LED Flashing etc).Am reasonably good at reading electrical drawings, however, what I am not good at is inverting myself under the dashboard!Is anybody able to save me from this ignominy?All ideas welcomed!Bob Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 7, 2016 Member Share Posted July 7, 2016 I've got the diagram: send me a Private Mail with your email address.... what I am not good at is inverting myself under the dashboard!Have you tried a smart 'phone?Jonathan Link to comment Share on other sites More sharing options...
Titanium7 Posted July 7, 2016 Share Posted July 7, 2016 Hi BobI have a wiring diagram for a CSR with standard gaugesSend me a message with your email address.Martyn Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 7, 2016 Member Share Posted July 7, 2016 How many dash variants are there on CSRs?Jonathan Link to comment Share on other sites More sharing options...
RFF Posted July 7, 2016 Author Share Posted July 7, 2016 Thank you both for your kind offers.Any tips on the reported upgrades that Caterham have issued re speedometer problems?Bob Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 7, 2016 Member Share Posted July 7, 2016 John Vine's the expert.I think the main points are: Setting the sensor gap Checking the LED (which you've already found) The Workshop Notice linked above. But i'm trying to think of a point of failure from the work needed for an ECU change that causes what you observe and still allows the other instruments to work.Jonathan Link to comment Share on other sites More sharing options...
sjmmarsh Posted July 7, 2016 Share Posted July 7, 2016 Lots of useful CSR stuff here including the wiring diagrams. Steve Link to comment Share on other sites More sharing options...
Hanns Per Posted July 8, 2016 Share Posted July 8, 2016 I myself switched to an MBE several years ago but this did not effect the speedo at all. The only speedo problems I had was that it interrupted occasionally. It must have been some erratic contact issue at the back of the speedo or a cable or plug becoming loose. I pressed with my hand onto the backside of the speedo (blind of course) and the speedo worked again fine, try this maybe it helps. Link to comment Share on other sites More sharing options...
NeilCSR Posted July 8, 2016 Share Posted July 8, 2016 ECU change shouldn't affect the speedo. I've been battling with an erratic (and occasionally non-operational speedo for the past two+ years since I got the car.I also changed the MBE ECU recently and this didn't help or exacerbate the speedo problemsThe earthing mod at the rear - adding a separate earth to sensor does help but I've found that the mod that makes the greatest difference is to mount the sensor on a remote bracket. The original sensor position on my car isn't central with the ring, only just over half the sensor points at the ring, but by creating a bracket (I've used a piece of 3mm stainless) it can be pointed properly towards the centre of the ring. It now works just about into three figures. Previously, even when the speedo didn't work, the LEDs still flashed. What I've done isn't quite perfect yet, probably going to remake the bracket as the angle isn't quite radial, which I'd guess is why it doesn't work at high speeds.It isn't just the gap that is critical, the sensor field should be covered by the ring, and the sensor should be positioned pointing radially to the driveshaft axis.Neil Link to comment Share on other sites More sharing options...
RFF Posted July 9, 2016 Author Share Posted July 9, 2016 Thank you Neil,I will fabricate one in the work shop on Monday. I take your point over the need to direct the censor at the center of the shaft,Robert. Link to comment Share on other sites More sharing options...
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