John Vine Posted March 26, 2021 Share Posted March 26, 2021 It's 1K ohm, not 1 ohm. Assuming the resistor is simply missing, there should be a mating connector for it in the loom already.JV Link to comment Share on other sites More sharing options...
simon_h Posted March 26, 2021 Share Posted March 26, 2021 The second speedo, if you take the grommet out it might have the rows of dip switches to change the cal. Mine looks similar from memory and isnt programmable by the trip button but has the switches behind the grommet Link to comment Share on other sites More sharing options...
John Vine Posted March 27, 2021 Share Posted March 27, 2021 Re #27:Good idea. Looking again at your second speedo, the odometer screen is black rather than green, and the date on the label is 30/04. AFAIK, the later version (green screen, pulse code) was introduced in 2005. So yours could well be the type programmed via dipswitches, as simon_h suggests.JV Link to comment Share on other sites More sharing options...
OrangeMax Posted March 27, 2021 Author Share Posted March 27, 2021 So, the 12v green wire from Pin #1 supplies the added voltage required for the speed sensor (reduced by the resistor)?Yes, the black tach is a dip switch version. Thank you for pointing that out. Is there a document covering the dip switch settings?OM Link to comment Share on other sites More sharing options...
John Vine Posted March 27, 2021 Share Posted March 27, 2021 Re #29:Some info on pull-up resistor here.Is there a document covering the dip switch settings?Dipswitch tableSpeedo infoJV Link to comment Share on other sites More sharing options...
OrangeMax Posted March 31, 2021 Author Share Posted March 31, 2021 Three cheers! I have a working speedometer, thanks to the great advice from the folks who frequent the tech section of the Lotus 7 Forum.Just in the rare case that others may find themselves with a similar challenging speedometer I'll recap the things that were required to get it working.1. The sensor distance to the trigger wheel was not correct, as it was not lighting on every tooth.2. Ground modification was not done. (Sometimes this is not required, but it can't hurt to do it)3. Sensor wire was going to the wrong pin on the speedometer. I changed it's location from pin #6 to Pin#7.4. The wrong code was set in the speedometer. Thanks to the folks here I was able to set in the correct code.5. There was not a 1K ohm .25w resistor between pin#1 and pin#7 wires. This was added.Thank you all again.OM Link to comment Share on other sites More sharing options...
John Vine Posted March 31, 2021 Share Posted March 31, 2021 Well, that's what I call a result! Excellent news, and well done for persisting with it.Re #23, did the "KPH" speedo on CC Parts website turn out to be "MPH" after all?JV Link to comment Share on other sites More sharing options...
OrangeMax Posted March 31, 2021 Author Share Posted March 31, 2021 Greetings John,According to the email I received from Caterham, yes it is. So its been ordered. Perhaps someone will need a Silver KPH speedometer in the near future!Thanks to you I had reason to be persistent. I'm truly glad this organization exists.OM Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted March 31, 2021 Share Posted March 31, 2021 Glad that you got it working OM. The last task to get it really accurate is to drive at a steady speed (such as 60mph / 100kph) and note your speed on a GPS device such as a sat nav and compare with your indicated speed on the speedo. Calculate the speed ratio (so if 60 on the satnav and 63 on the speedo, that would be 0.952), now take the number of pulses set in the speedo and adjust by that ratio, so if say 024581, adjust by multiplying by 0.952 to a value of 023401. Link to comment Share on other sites More sharing options...
John Vine Posted March 31, 2021 Share Posted March 31, 2021 #33: Good news about the speedo. #34: Indeed. And you can adopt the same method to fine-tune the odometer instead if you wish. This is what I do, as I much prefer to have accurate travel distances at the price of (generally) a slightly optimistic speed reading. You can easily get down to an accuracy of +/- 0.5%.JV Link to comment Share on other sites More sharing options...
John Vine Posted April 1, 2021 Share Posted April 1, 2021 Hi James,In your example in #34, isn't the calculation the wrong way round? To reduce the indicated speed on the speedo, surely you increase the pulse code? In other words, you would divide 024581 by 0.952, to give 25820.JV Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted April 1, 2021 Share Posted April 1, 2021 Yes, that is correct John. Link to comment Share on other sites More sharing options...
John Vine Posted April 1, 2021 Share Posted April 1, 2021 Thanks for the confirmation. I feared I was losing my marbles!JV Link to comment Share on other sites More sharing options...
OrangeMax Posted April 16, 2021 Author Share Posted April 16, 2021 Greetings,The Silver MPH speedometer showed up from Caterham. It's rather nice having the correct speedometer in the car working as it should. I set it for my current tire size as shown in the chart. It's a bit fast compared with the GPS speedometer but I can tune that out. My understanding of the procedure is to drive the car at 60 mph as shown on the speedometer and compare it to the GPS Speedometer. If the GPS is indicating 65 MPH when the car speedometer is showing 60 MPH. The formula is this: 60/65=.923 Then divide the Pulse Code (023855/.923=025845)?(example numbers shown, no test done yet).OM Link to comment Share on other sites More sharing options...
John Vine Posted April 16, 2021 Share Posted April 16, 2021 Pleased to hear you've now got the pukka speedo. (I have the silver dials, too.)In your example (speedo 60 GPS 65), your formula is the wrong way round. To increase the speedo reading from 60 to 65, you need to reduce the pulse code. So you need to multiply the 023855 by 0.923, giving 022018.However, you say that the speedo actually over-reads at the moment compared to the GPS. If that's the case, your formula is correct.JV Link to comment Share on other sites More sharing options...
OrangeMax Posted April 21, 2021 Author Share Posted April 21, 2021 So to increase car mounted Speedometer reading to match GPS you would multiply.To decrease the car mounted Speedometer reading to match GPS you would divide.OM Link to comment Share on other sites More sharing options...
John Vine Posted April 21, 2021 Share Posted April 21, 2021 So to increase car mounted Speedometer reading to match GPS you would multiply. To decrease the car mounted Speedometer reading to match GPS you would divide.Yes, provided your multiplier or divisor is less than 1 (in the example, 0.923).In other words:To increase the speedo reading to match the GPS, you need to reduce the value of the pulse code (which multiplying by 0.923 would do).To decrease the speedo reading to match the GPS, you need to increase the the value of the pulse code (which dividing by 0.923 would do).JV Link to comment Share on other sites More sharing options...
OrangeMax Posted April 30, 2021 Author Share Posted April 30, 2021 So I took the car out for a drive today and did the final setup on the speedometer. It's now about dead on with the GPS speedometer, so I'm calling this job done! Thanks to everyone who offered their experience, especially John Vine. Now its on to fine tuning the roller barrel throttles and some fine tuning on the tach. Then off to get the car titled and Licensed!OM Link to comment Share on other sites More sharing options...
John Vine Posted April 30, 2021 Share Posted April 30, 2021 Good news. Pleased to help, and glad it worked out ok.CC published a Workshop Notice (WN608) on how to set up RBs on R400/R500 models. If you'd like a copy, send me a Private Message with your email address.JV Link to comment Share on other sites More sharing options...
revilla Posted December 30, 2021 Share Posted December 30, 2021 Did anyone ever manage to identify the type of 8-pin connector used please? It's not one I recognise. I need to make up a test harness and I'd like to get hold of a couple of connectors. I've emailed Caerbont technical support and not had a reply; I've tried following up with a phone call but they are now closed until Jan 4th. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted December 30, 2021 Member Share Posted December 30, 2021 I haven't seen any new information appear.This is John's photo:Speedo%20plug_with%20arrow_1.jpgSpeedo%20plug_with%20arrow_1.jpg Could that be the same that VDO use:https://vdo-webshop.nl/en/connectors/739-vdo-viewline-connector-set-8-pin-7640178728493.html8-pin MQS Connector with contactsManufacturer: Hirschmann of Tyco?Happy ChristmasJonathan Link to comment Share on other sites More sharing options...
revilla Posted December 30, 2021 Share Posted December 30, 2021 Hmmm I dont think that's quite the same Jonathan, but I do think I might have found it now:https://uk.rs-online.com/web/p/wire-housings-plugs/3628768?cm_mmc=UK-PLA-DS3A-_-google-_-PLA_UK_EN_Connectors_MOB_Whoop-_-Wire+Housings+%26+Plugs_Whoop-_-3628768&matchtype=&aud-832474875011:pla-322788455414&gclid=CjwKCAiAzrWOBhBjEiwAq85QZ-yrCSB-1clQNwuYsAAiKx1DCmLE7XJbeCZ8x3p3VCAjyMT00wnHShoCAeEQAvD_BwE&gclsrc=aw.dsMerry Christmas to you too! Link to comment Share on other sites More sharing options...
revilla Posted December 30, 2021 Share Posted December 30, 2021 (I realised it looked just like the central portion of the immobiliser connector). Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted December 30, 2021 Member Share Posted December 30, 2021 Well done.So is "TE MQS" a different family from "TE Multilock 040"?Jonathan Link to comment Share on other sites More sharing options...
revilla Posted December 30, 2021 Share Posted December 30, 2021 Yes they are different. The terminals are different and designed to latch into different housings. The "040" bit is the male terminal width in thousands of an inch I think (approx 1mm). There's a similar 070 series. The immobiliser connector is a hybrid housing with some 070 terminals (at the ends) and some 040 terminals (in the middle bit). So I'm familiar with crimping these terminals (they're too small for a regular single-step F crimp tool), removing them from the housing etc.MQS Female Terminal:Multilock 040 Female Terminal: Link to comment Share on other sites More sharing options...
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