ThreePointFive Posted December 6, 2021 Share Posted December 6, 2021 Having done the TD5 instrument conversion, I need to confirm if the speedo is now working as I suspect it's not. The problem is, I can't get up to any speed on my property to test it so the only way I will know if it works is on the way to the MOT. And if it doesn't work, that's a failed MOT. Is there any (safe) way to fool the speedo into working for a test while stationary? I'm thinking raising a wheel/axle, but I know the T-box might not like the differece in speed if the other axle is not moving. Any ideas expect for breaking the law much appreciated. Quote Link to comment Share on other sites More sharing options...
Quagmire Posted December 6, 2021 Share Posted December 6, 2021 Connect the green doofer that goes into the gearbox to some kind of drill chuck and spin it up? 1 1 Quote Link to comment Share on other sites More sharing options...
miketomcat Posted December 6, 2021 Share Posted December 6, 2021 I might be wrong but I don't think a working Speedo is part of the mot yes it must display mileage but I've never seen them test it to see it show speed. I know for a fact my dad took a kit car for an MOT where the Speedo only worked in reverse (he sorted it later) and that still passed but it was a few years ago. Mike Quote Link to comment Share on other sites More sharing options...
western Posted December 6, 2021 Share Posted December 6, 2021 As Quagmire says, remove the transducer & spin the drive square end the speedo needle should move, it will need a 12v supply to make it operate 1 Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted December 6, 2021 Author Share Posted December 6, 2021 8 minutes ago, Quagmire said: Connect the green doofer that goes into the gearbox to some kind of drill chuck and spin it up? Thats not a bad idea... 5 minutes ago, miketomcat said: I might be wrong but I don't think a working Speedo is part of the mot yes it must display mileage but I've never seen them test it to see it show speed. I know for a fact my dad took a kit car for an MOT where the Speedo only worked in reverse (he sorted it later) and that still passed but it was a few years ago. Mike I did check and it read as though if fitted, it must work but I could re-read it. Being able to run it up reliably in the garage and know I should be seeing a response will make it a lot easier to diagnose though. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted December 7, 2021 Share Posted December 7, 2021 5 hours ago, ThreePointFive said: Thats not a bad idea... I did check and it read as though if fitted, it must work but I could re-read it. Being able to run it up reliably in the garage and know I should be seeing a response will make it a lot easier to diagnose though. Before I did the td5 speedo conversion, my old speedo was dead for I think 2 MOTs, never queried. Quote Link to comment Share on other sites More sharing options...
Troll Hunter Posted December 7, 2021 Share Posted December 7, 2021 If you've got axle stands, or some suitable blocking, raise both rear wheels for two wheel drive, or all four wheels for four-wheel drive, off the ground and run the engine as normal. If you also have a rev counter, or even just a hand-held tachometer, you can compare indicated speed with indicated rpm and get at least an idea of how accurate/inaccurate the speedometer is. Mike Quote Link to comment Share on other sites More sharing options...
TSD Posted December 7, 2021 Share Posted December 7, 2021 16 hours ago, miketomcat said: ... I don't think a working Speedo is part of the mot yes it must display mileage but ... I've got several MoT certs where the mileage is entered as 'Unreadable' without comment. For a while the Ibex had a broken VDO speedo where the LCD mileage readout was blank (and the needle went straight to 180mph as soon as the car started moving). Quote Link to comment Share on other sites More sharing options...
pat_pending Posted December 7, 2021 Share Posted December 7, 2021 It's one of those oddities in the test, if it's obviously not working it's a fail, but there is no actual "test" to check it's working. However when using a decelerometer (as opposed to rollers) to test the brakes, it would be obvious whether it was working or not. There's also no requirement for it to display the correct or in fact any mileage reading. Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted December 20, 2021 Author Share Posted December 20, 2021 Finally tested the speedo, no drill/equipment/additional live feeds were needed, just put the ignition in II position as the provides the positive and negative paths. I could get it to show 10mph only spinning it by hand which seems unrealistically fast for what must be 100rpm at most, but at least I know the gauge is getting a feed, accuracy is another issue that I will have to test on the road. 1 Quote Link to comment Share on other sites More sharing options...
western Posted December 20, 2021 Share Posted December 20, 2021 Yep, that works then. 1 Quote Link to comment Share on other sites More sharing options...
pete3000 Posted December 22, 2021 Share Posted December 22, 2021 you can use a tomtom or other gps to calibrate it on the way to the mot...... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.