Jools Powell Posted September 1 Share Posted September 1 Just collected my first Caterham and yesterday on the 2nd leg of our journey home the Speedo has decided not to work. What is it likely to be? Link to comment Share on other sites More sharing options...
Jools Powell Posted September 1 Author Share Posted September 1 A thought had just occurred to me, is that the car had some work on the diff before we picked it up. Is it likely to be something to do with that? It's an 08 and maybe it wasn't working straight away and I was too excited to notice on the first short leg. Link to comment Share on other sites More sharing options...
supersport_140 Posted September 1 Share Posted September 1 The wheel speed sensor on the rear wheel. Quite an easy fix. Link to comment Share on other sites More sharing options...
supersport_140 Posted September 1 Share Posted September 1 https://www.caterhamlotus7.club/guides/158_electrical/speedometers/ Link to comment Share on other sites More sharing options...
Jonathan Kay Posted September 1 Share Posted September 1 1 hour ago, supersport_140 said: https://www.caterhamlotus7.club/guides/158_electrical/speedometers/ Yes, start with the Guide. identify which type you have, and please let us know. Jonathan Link to comment Share on other sites More sharing options...
Jonathan Kay Posted September 1 Share Posted September 1 1 hour ago, Jools Powell said: Just collected my first Caterham and yesterday on the 2nd leg of our journey home the Speedo has decided not to work. If you're considering asking the seller to sort this out I suggest letting them know without delay Jonathan 1 Link to comment Share on other sites More sharing options...
BigCol Posted September 2 Share Posted September 2 (edited) If the seller can’t sort it and the sensor is toast, Minty (aka Chris Mintoft of Redline Components) can get a new one to you the next day. Well he did for me last week! Edited September 3 by BigCol 1 Link to comment Share on other sites More sharing options...
John Vine Posted September 3 Share Posted September 3 On 01/09/2024 at 07:17, Jools Powell said: Just collected my first Caterham and yesterday on the 2nd leg of our journey home the Speedo has decided not to work. What is it likely to be? Can you tell us a bit more? What model of 7? Did the speedo needle simply sit on zero or was there some movement? I doubt the diff work is significant, unless the sensor wiring/adjustment was damaged/altered. JV Link to comment Share on other sites More sharing options...
Jools Powell Posted September 3 Author Share Posted September 3 The 11 hours ago, John Vine said: Can you tell us a bit more? What model of 7? Did the speedo needle simply sit on zero or was there some movement? I doubt the diff work is significant, unless the sensor wiring/adjustment was damaged/altered. JV The speedo sprang into life on the last leg of the journey from Winchester to Cornwall however every now and again it still would just drop to zero for a few minutes and not move then bounce back up. I'm working this week and haven't had a chance to have a look at it. The car is a 08 sigma engine 125 SV. I know there is an LED reading a cog like thing on the back wheel but I'm supposing it's probably a dogy conection. Link to comment Share on other sites More sharing options...
ScottR400D Posted September 3 Share Posted September 3 28 minutes ago, Jools Powell said: The The speedo sprang into life on the last leg of the journey from Winchester to Cornwall however every now and again it still would just drop to zero for a few minutes and not move then bounce back up. I'm working this week and haven't had a chance to have a look at it. The car is a 08 sigma engine 125 SV. I know there is an LED reading a cog like thing on the back wheel but I'm supposing it's probably a dogy conection. The proximity sensor needs to be about 1mm from the ‘cog like thing’. Closer or further away it doesn’t work but the exact distance can vary. Very common, just need adjusting. Lots of us have been there. It could well have been disturbed when the diff was removed. 2 Link to comment Share on other sites More sharing options...
PlastererPete Posted September 3 Share Posted September 3 I did this on mine as I had a "wobbly" speedo needle for quite some time. jack the back drivers wheel up switched the ignition on and span the rear wheel. I had a light on mine which illuminated everytime a trigger wheel tooth went past. Took about 5-10mins to get the distance correct. After that its been fine. Link to comment Share on other sites More sharing options...
ScottR400D Posted September 3 Share Posted September 3 As far as I know they all have the LED on the sensor. It’s not that reliable a guide. It’s easy to get the light flashing spinning the wheel but then you can find the speedo works up to maybe 45mph then starts to drop out. It needs adjusting a tiny bit at a time till the speedo works at all speeds or at least up to a speed that covers your needs. When I had my diff out to fit a Tracsport the speedo went awol. As said it’s only a few minutes work to adjust but sometimes it takes a few tries. There are two types of sensor, the layer one is easier to set and more reliable. I’m talking about the earlier one. Link to comment Share on other sites More sharing options...
JetSepter Posted September 4 Share Posted September 4 Jools The speedos are very iffy, it seems. I have had a new sensor and frequent adjustment of mine, but every now and again - like on last Sunday's Cornwall blat - it decides that bouncing up and down from zero to 70 is much more fun than a boringly constant indication. I back mine up with an old Garmin GPS mounted on the steering wheel, set to show trip and speed info. Quite a comfort if you do finish up cruising along with the boys in blue behind you... Link to comment Share on other sites More sharing options...
supersport_140 Posted September 4 Share Posted September 4 It took a few attempts to get mine right. Link to comment Share on other sites More sharing options...
ScottR400D Posted September 4 Share Posted September 4 1 hour ago, JetSepter said: Jools The speedos are very iffy, it seems. I have had a new sensor and frequent adjustment of mine, but every now and again - like on last Sunday's Cornwall blat - it decides that bouncing up and down from zero to 70 is much more fun than a boringly constant indication. I back mine up with an old Garmin GPS mounted on the steering wheel, set to show trip and speed info. Quite a comfort if you do finish up cruising along with the boys in blue behind you... The speedos are fine, it’s just the sensor adjustment. Link to comment Share on other sites More sharing options...
John Vine Posted September 5 Share Posted September 5 19 hours ago, ScottR400D said: The speedos are fine, it’s just the sensor adjustment. Agree about the speedos. But electrical interference in the loom can also cause erratic behaviour on earlier cars (around 2008, say). The fix is described in the guide referenced upthread. JV Link to comment Share on other sites More sharing options...
John Vine Posted September 5 Share Posted September 5 On 03/09/2024 at 20:41, Jools Powell said: The The speedo sprang into life on the last leg of the journey from Winchester to Cornwall however every now and again it still would just drop to zero for a few minutes and not move then bounce back up. I'm working this week and haven't had a chance to have a look at it. The car is a 08 sigma engine 125 SV. I know there is an LED reading a cog like thing on the back wheel but I'm supposing it's probably a dogy conection. Thanks for the feedback. Sounds to me like a problem with the sensor air-gap. The fix is in the Guide referenced earlier. JV Link to comment Share on other sites More sharing options...
Jools Powell Posted September 5 Author Share Posted September 5 Thanks everybody for the info. I'll have a look on the weekend. Link to comment Share on other sites More sharing options...
ScottR400D Posted September 5 Share Posted September 5 As an afterthought, before you make any adjustments check what the gap is at a few teeth. If it’s significantly less than 1mm it’s probably too close. Much more than 1mm, too far away. That will give a you a clue as to which way to adjust. Of course, if it’s close to 1mm you will have no idea which way to go! Though I’d go a touch closer first. When you tighten the lock nuts check the gap again. It’s easy to move the sensor when nipping up the nuts. 1 Link to comment Share on other sites More sharing options...
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