phatcat

Yes. You're absolutely right! I was wondering if anyone would have picked up on that before I got back! I was staring at the WN this morning and shaking my head feeling like a proper idiot, then pulled myself together and ran out to the garage. (It's odd that the sensor LED still worked given it was wired wrong, but no doubt that all makes sense to sparkies). I can confirm it's all fixed. Thanks to all for help. on the sensor: brown = +ve blue = -ve (earth) black = signal on the loom: green = +ve black = -ve (earth) yellow = signal Something vaguely useful I learned though to share: Rather than jumping in the car for a drive to test the wiring and sensor for each attempted fix, here's what you do (assuming you have a relatively recent 7 model): 1. loosen off the nuts on rear wheel on drivers side. 2. jack the car up, stick it on axle stands, and take the rear wheel off. 3 turn car power on (key turned to first position so you can hear the fuel pump prime). 4. rotate the brake disc and the wheel sensor LED should flash as it passes the grooved teeth on the disc behind. 5. forget a feeler gauge (the correct gap seems to vary anyway), just slowly turn the brake disc, and make sure you get on/off for each tooth all the way around, and if not, adjust the sensor in/out as needed via the nuts. note that the toothed wheel may not be perfectly round, so its important to do a full wheel rotation to check for any dead spots. also note that you need to do this test again after you have tightened the sensor in place. 6. leave the car jacked up, and kill the power via battery master switch. 7. pull out speedo from dash via releasing thumbscrews at back and disconnect it. (a bracket and a couple of wrinkly washers will probably fall into the footwell - try to catch them as you undo the thumbscrews). 8. put multimeter probe into yellow wire socket in the speedo connector that is now hanging out of the dash. 9. earth other mulitmeter probe on chassis (I used a metal door fastener as it's convenient). 10. set multimeter to read DC voltage, e.g. 20v DC and turn on multimeter. 11. turn on power, multimeter should either read 12v or 0v. 12. slowly turn the rear brake disc, the voltage should now alternate between 12v and 0v as you turn. (If not, I guess you may have a bad earth - see the WN, or perhaps some other wiring/connection issue, perhaps try continuity tests). 13. having confirmed all is well, put the rear wheel back on, get car back on the ground and tighten up the wheel. 14. reconnect the the speedo and calibrate it if it's a new speedo (see chart on other posts). 15. go for a blat and check the speedo vs GPS. 16. if all is well, properly reattach the speedo to its bracket behind the dash. Interestingly after all this, the old speedo now has a working LED again (I guess it likes the new earth). But it still wobbles its needle and overreads the speed (possibly due to damage from having a bad earth for 3490 miles, who knows?) I fitted the new speedo again, and no wobble - rock solid and speed matches GPS. Hopefully it will stay that way this time...

Not my blog as it goes! Looking at the sensor sub-loom on the caterham website, it's not an uninterrupted wire that connects from the sensor connector all the way to the speedo connector as the caterham part has an econoseal connector at both ends. So I expect the yellow wire becomes the red/white wire, but I guess I'll confirm that when I do some tests tomorrow (assuming it passes the continuity test). I'll report back here if/when I find out more. https://caterhamparts.co.uk/looms/2150-sub-loom-wheelspeed-sensor.html

> Where was the other lead of the meter connected for each of those? To a fastener screw on the body of the car. (A door fastener). I think the biggest problem in trying to fix this fault is not knowing if you've fixed it without taking the car out and all the jacking up/down to get at the stuff behind the wheel. I expect an auto-electrician would know the source of the fault in minutes, maybe I should phone one...

Here's what I did today: 1. As per the Caterham work notice, I drilled a hole in the chassis tube at the point indicated by the WN. I then ran a new, shortened, earth lead in case the old one was no good, crimped the wire with an eye connector, tapped the hole, and screwed in a bolt to secure the lead to the new earth point. I then crimped the new earth lead direct to the black lead on the sensor, as before. 2. Double-checked the LED flashing on the sensor went on/off as the wheel turned. I tried 1mm with a feeler gauge as suggested, but that just made the light stay on all the time, and I had to back it out to ~1.3mm. 3. Refit the old speedo in case the new speedo was the issue. 4. Checked the wires in the econoseal connector were not loose, then disconnected and reconnected it. 5. Checked all the fuses. But, still no speed showing At this point I'd got bored of taking the car off the axle stands, out for a 1 min drive to confirm no speed reading, then jacking back up again. So I thought - maybe I can check with a multimeter if there is a pulse signal being received by the speedo? So, I took the speedo out of the dash and pulled the connection out of the back of the speedo. Then I hung the connector out of the dash, and stuck a pin in each wired hole to get the voltage readings, and got the following results: Green - 11.8v Red/white wire - zero Black - zero Yellow - 11.9v I then turned the rear wheel for the sensor, which flashed away merrily, and watched the voltages of each of the above connections - they didn't vary at all. I then tried swiching the multimeter to amps, but again no change when I span the wheel. But I really have no clue what I am doing with a multimeter, so I gave up at this point. So I know it's not the fuses or the speedo, and I've tried 3 different earths. I'm starting to get suspicious of the sensor and/or the wiring loom. To eliminate the wiring loom as the issue, I'm thinking I should kill the power via the battery master switch, connect pins at both ends of the loom to the multimeter, switch it to the continuity test setting and see if it buzzes. This is turning into a lot of effort!

Thanks to Jonathan, I now have the workshop notice, will read it through and then heading back to the garage...

I've assumed the sensor gap must be ok, because the speedo was working perfectly as per GPS until it decided to go mental again. Though I guess I should check if it has just become loosened. Cable length could indeed be an issue. I intend to reduce the length once I get my hands on the workshop notice about where the official earth point is. I'm itching to get out there and have another go, but I'm trying to avoid fiddling with it until I get that info...

Thanks Jonathan. I've sent John Vine a BM asking for "WN572 - Speedometer sensor groundwire installation", so I'll take a look when I get that. Seems the problem is common enough for Caterham to have listed a part for it: https://caterhamparts.co.uk/senders/5685-wheel-speed-sensor.html For the moment, my earth point is at the same location as the bottom-right picture here: https://fernlahone.wordpress.com/tag/caterham-7-speedo-faults/ I haven't attached my ground wire through the connector though, like his other pic shows, but rather pulled out the black sensor wire from the connector and directly attached my ground cable to that, hoping this would give a better connection. My earth cable is currently crimped to the black sensor cable, but I might try soldering it to see if that helps. I did try the earth wire at various points on the chassis, and very few lit the sensor LED. The brake pipe T did, which is why I used it, but then so did the original connection. I wonder if the workshop notice has a different earth point? Hopefully I'll be able to check later. I'll report back if/when I get it working.

Having some speedometer issues, a bit of history here: 1. When I first got the car, the speedo generally worked fine, but the needle was a little wobblier than it should have been. 2. I went on a few track days and at some point in the day the speedo would go bonkers and then stop reading, but after a bit of road driving it would go back to its normal, minor wobbles. 3. The speedo sort of died a couple of weeks ago (the LCD display stopped working on the way to get an MOT, but the speed was still reading ok and I got my MOT ok). 4. So I fitted a brand new speedo, and it was reading rock-solid as per GPS, no needle wobbles. Perfect, I thought, all was well. 5. I go out for a more spirited drive today, and it's suddenly all over the place. 6. I read up on forums and they say to run a new earth lead from the sensor. I guess I must have messed this up, because now, although I get a flashing LCD on the sensor at the wheel, I now get no speed reading at all on the speedo (the speedo LCD is fine). So now I'm wondering what to do? It seems unlikely I've blown a fuse as the sensor LCD and speedo LCD still work, but I can check tomorrow as I don't know which fuse it is so I'd have to go through all of them I guess. I'll have another fiddle at improving the earth too, but I'm wondering if, given that the LCD on the wheel won't flash without an earth, if it's an earth issue at all? Maybe it's just a bad sensor. The sensor gap must be ok as I haven't adjusted it since it was working. But, if it's a bad sensor, why does it flash when I move the wheel? I guess my earth is just worse than the original, as it's gone from mental to no reading at all. Or maybe it's the non-earth connections, but they still click together with the econoseal connector so that seems unlikely unless it's the connector itself. When running my new earth, I just pulled out the black wire from the sensor, crimped another cable to that, and ran it to the brake pipe/de-dion connection, so altogether its about 2.5 feet of wire from earth point to sensor. The sensor is no longer connected to the original earth. Any thoughts on the best way to go about determining the cause? How do I know if my earth is good enough, or whether there is a problem with the other connections? I'm guessing the answer involves a multimeter but I wouldn't know what readings I was looking for? I'm pretty clueless with electrics. Wild guess - is it stick one terminal on the chassis, and expect +12v on the green, 0 on the black, and yellow should be reading a low variable output from the sensor when you turn the wheel? Thanks for any help.

Used the appropriate setting from the table, and it was only 1mph above the GPS reading (with brand new tyres)

Great, thank you - found this stuff: You can press the speedo button in as you turn the ignition and a menu comes up and enter a code. On electronic models, hold the central speedo button and turn the ignition to the on position, screen should change to 'Set PPU' (if it says 'DTS PPU', press it again to switch mode). Press the button again and the currently set code will display. Each number will then flash in sequence - press the button on each number until the correct code is entered. When the whole number flashes, press the button again and the display will say "DONE" Earlier models have a removable rubber cap on the back of the speedo case which contains dip switches instead. Most of them seem to be Caerbont speedos. They have pdfs here with fuller instructions including a "drive to set" option for electronic speedos. There are several links under the speedometer picture, depending on your model, including a pdf with all the dip switch settings. http://www.caigauge.com/product-instructions I also found a table for 7s: Also, from another post it's 034187 for a 160. It sounds like you can tweak it with in-between numbers as someone stated that 038457 worked well for him with the CR322s. Will go and fiddle, then go for another spin with a GPS speedo on my phone. This looks like a good candidate for a tech article if someone could gather all the info together for all the various speedos/tyres/wheels used by Caterham over the years.

(On a 2012 1.6 Sigma Roadsport): I had a speedo that was working just fine, except that the digital odometer display failed. I ordered a new speedo from Caterham and fitted it. This new one is massively overreading - 80mph at ~10mph, and maxed at 160mph at ~30mph. Also, for a 15 mile drive it registered 61 miles on the odometer. Do I need to do something to calibrate the speedo? All I did was take out the old one, plug the cable in the new one and go on a test drive.

Price drop bump.

2012 Caterham Academy car (1.6 Sigma Roadsport 125, 5-speed box) White with red stripes Never Raced Factory Built 2 Owners 3600 miles, probably 1/3 of that on track (currently showing lower mileage as speedo just replaced). Well maintained mechanically - professionally serviced + MOT'd just this month so nothing needs doing. Service history (all done by Ollie at Phoenix Motorsports): 04/15 2443 05/16 3405 05/17 (~3550 - speedo failed on the way to service ) Just had new speedo, new brake pads all round, and new belt fitted. One set of silver alloys/tyres are pretty much brand new, 200 miles or so (CR322 tyres) - see options Lowered floor Plumbed extinguisher Full cage with FIA spec padding 6 point driver / 4 point passenger harnesses Quick release steering wheel Full weather kit Rain light Heated windscreen Custom mirrors Tillet seats (though I can't find the nuts/bolts for one of them, so they'd need to be ordered from Caterham). Currently has a custom moulded seat for helmet clearance (and wide hips!) - a couple of other people have driven it with this seat and like it, so included in sale cost if you're tall/big-boned. Cosmetically has a fair few chips of paint missing thanks to previous owner. Price: £15500 Located in Bolton, Lancs ​ Selling because I haven't really used it in the last year other than maintenance runs. Pictures here (note there are some white marks in the cabin which is just removable glue from duct tape, not had the willpower/time/patience to remove it yet): https://www.dropbox.com/sh/l3vw4yzlzw15cak/AABef4IeGihTb_Swl_4I5VcSa Separately negotiable options: Spare set of (dark grey) alloys (and well worn tyres) - one wheel pictured - £150 extra with sale (sale includes one set of your choosing with the tyres they have on) Half doors - £35 extra with sale Might also be able to throw in some oil, brake fluid and spare brake pads Also have a brian james sprint shuttle trailer in nice condition for sale which i haven't advertised yet - prolly worth around £5k (stored a couple of miles away) None of this is available to separate offers until the car is sold

Yes, just been out and changed them. The only real difference between the ones I took off and the ones I put on was a slight design difference with a split down the middle of the pad (effectively making two smaller pads). Thanks for the help. I'm all gtg for Tuesday now :-)

Thanks, yep, they look like that. Hopefully the fitting/calipers didn't change between 2004 and 2012. Now if I could just get my guests to leave, I'll be able to find out...

Thanks Mankee. I still have the problem of getting some front pads put on before Tuesday, so I did some digging through the garage... I found some pads with a bit of life left in them which I think are from my old 2004 K-series Academy car. These have 4 indentations on them, and are labelled as follows: Two of: FER3441F GF 456572 Two of: FER3441F GF 109037 Not sure if the last part is the serial no? they all look the same to me. All four have a large "L" imprinted on the metal, maybe that means left? but seems odd given they all have it. Questions: Am I right in thinking that these are front pads? Any idea if these pads will fit my 2012 Sigma car? (I've got guests around atm, so I won't be able to check until tomorrow afternoon). Thanks.

Hi all, I phoned Caterham and ordered a full set of pads (i.e. front and rear) for my 2012 Sigma Academy car. Only one set of pads (i.e. front or rear) have turned up so far, and I need to replace my front pads before a track day on Tuesday at Oulton. I asked for "standard" pads, but istr on my previous K-series Academy car, they were Mintex all-round, whereas the pads that turned up are: AP Racing 225 (CP3915-42-DS25HP) They have 2 indentations on them, which I assume indicates that they are for 2 piston calipers, but no idea tbh as I've not changed the pads up until now. Questions: 1. Are the pads that I received front or rear pads? (or are they the same front and rear on my car?) 2. If they are front pads, and non-standard? will fitting them with the standard rear pads cause more than a minor imbalance? 3. Am I right in thinking that fitting the front pads is an easy job, but fitting rears requires specialist tools? 4. Do I need to bed the pads in before a track day? (I'm super-busy this weekend, so wasn't planning on any blatting). Thanks for any help.

Thanks chaps. MOT booked )

I'm sure this has been asked before (or maybe it's just too daft), but anyway: I've been doing some pre-MOT checks on the car, and reading through the goverment MOT manual at http://www.motinfo.gov.uk/htdocs, I came across this: 1. Check the driver’s and all passengers’ seats for security. 2. Check that the backrests of all seats (front and rear) can be secured in their normal upright position. 3. Check that the driver’s seat position can be adjusted forwards and backwards and secured in the selected positions. I have a bag seat in my 7 (actually that's overstating it, as the base is just 5mm foam stuck to the floor so my bum goes numb within 30 mins or so!) At any rate, I can't get in the car with a standard seat, let alone drive it. So my seat cannot be secured in any position unless leaning against the metal counts - its just a bunch of foam and duct tape. Is this a problem? Do I need to fit a tillet seat and trailer it to the MOT station? Is there anything else (a relatively new) 7 often fails on? (this is the car's first MOT, and I sold my last 7 before it was due, so a bit clueless). It's an Academy car with full cage if it makes a difference. I've disconnected the rain light. Thanks.

I asked Caterham for a couple of SPA convex mirrors to fit to my rollcage. They gave me a rear-view mirror to fit to the rollcage which has an exhaust bracket welded on to it - so no problems there. But they also gave me a driver's wing mirror + loose exhaust bracket. Does anyone have any instructions or close-up pics on how you use the exhaust bracket to mount the wing mirror to the cage? I want to attach it to the inside of the car if possible, attached to the cage upside down so-to-speak. Thanks.

Overtook a space rocket in my 7 😬 Ok, so it was on the back of a lorry on the M6 at the time... (14/03/05 ~17:30), but still one up for the 7, and hopefuly will stop my girlfriend boasting that she overtook the fastest car in the world in her Yaris (Thrust SSC - also on the M6!) The rocket was called a "starchaser" - didn't know Britain was still in the space race...

Anyone...? Bueller... Bueller...?

I noticed that my oil pressure was a bit low at idle, so I set about checking the oil level. The 1.6K engine has a big label on it saying check oil level when hot - fair enough. However, out of interest, I took a reading when cold and a reading when hot. When cold, the oil level was slightly above max, and when hot it was slightly below min. This seems odd, as I'd expect hot oil to expand and give a higher oil level reading, but apparently not. 1. I assume this is normal? 2. Why?

Ok Thanks. I'll try the jimchap method and see how that fits.

Quick one: The sticky foam pads that Caterham attached to the car that the bonnet sits on when the chassis is delivered - Do I take these off when I have finished the build, before putting the bonnet back on?