Ian C Posted October 29, 2015 Share Posted October 29, 2015 Righto, this has been going on for ages as I have limited time to plug away at these thing these days I've had RLTC installed in the Supra since about 2004 and after initial setup and tweaking it's been sat under the passenger carpet for almost a decade merrily working just fine. Then, a while back, I removed it to test someone else's RLTC and bosh, it's never worked properly since The problem was bonkers cutting for no reason. I hooked up the lappie and ran a trace, and the rear wheels report back random numbers, anything up to the max 256mph. but - it only happens once they get over a certain speed. See attached graph for what I mean - I jacked the rear up and ran it in 3rd to carefully raise and drop the rear wheel speeds and you can see that it's smooth as it should be up to about 35 on one wheel (purple) and about 40 on the other (yellow). You can lower the speed back down again and they start behaving again. The fronts are fine, I've datalogged them on the move and they don't miss a beat. I swapped the wires going into the RLTC unit so that front left became front right, rear left became rear right, and vica versa. This meant that if the ABS sensors were dodgy, the problem should move to the other inputs. I've looked back at my recordings and the problem shifted to Front left and Rear left and I can't really explain that now (something might have confused matters by changing the channels assigned to the wheels). I was convinced that the problems remained on the same inputs, meaning it's the unit at fault but now I can't really say 100% that was the case. Anyway, I sent the unit back to Racelogic, they tested it and said it worked fine (£100 please ). I've just tested it again and it's still doing the same thing. If it was the wiring or the plug in the RLTC unit I'd not expect this behaviour, it should be bad all the time or when cables are moved, NOT triggered by going over a certain wheel speed. If it was the ABS sensors I'd expect and ABS fault to come on by now! And the only change after x number of years of flawless functioning was me disturbing the unit by unplugging it. Thoughts? -Ian Quote Link to comment Share on other sites More sharing options...
Abz Posted October 29, 2015 Share Posted October 29, 2015 Sorry Ian, I can not help with the technicalities of this but I do have a RLTC at home somewhere that I have not fitted which I am happy for you to borrow to help you troubleshoot. Does seem very odd this happened when you disconnected the unit, sure it wasn't perhaps happening before? Just that TC didn't kick in? Quote Link to comment Share on other sites More sharing options...
Ian C Posted October 29, 2015 Author Share Posted October 29, 2015 Sorry Ian, I can not help with the technicalities of this but I do have a RLTC at home somewhere that I have not fitted which I am happy for you to borrow to help you troubleshoot. Does seem very odd this happened when you disconnected the unit, sure it wasn't perhaps happening before? Just that TC didn't kick in? That would be awesome if you could! I'll PM you my address and I'll see you right for shipping etc It was fine before, very obvious when this happens as the unit keeps thinking the rears are going 200kmh faster than the front so it cuts the injectors constantly and randomly. Quote Link to comment Share on other sites More sharing options...
Ian C Posted October 29, 2015 Author Share Posted October 29, 2015 I've dug around my old files and realised that one cause of confusion in all this, is that they made me upgrade to v2 of the software. That seems to have changed the wheel channel allocations on saved files and I don't think I noticed a the time, so all my wire-swapping test is rendered questionable. I can try it again but I'd much rather try Abz's spare unit Quote Link to comment Share on other sites More sharing options...
TuneR Posted October 29, 2015 Share Posted October 29, 2015 Im not sure this will be of help but an old S2000 i had used to throw the ABS light over a certain speed. Turned out it was the ABS ring on one driveshift not aligned properly but just enough so it was only coming out of alignment over that certain speed.... Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 29, 2015 Share Posted October 29, 2015 ABS ring corroded, faulty sensor or poor connection. If you know someone with a scope it's trivial to look at the output of each sensor at the RLTC. Also check thr RLTC connector, they use a REALLY REALLY junk one and they play up. Quote Link to comment Share on other sites More sharing options...
Ian C Posted October 30, 2015 Author Share Posted October 30, 2015 Thanks I've got an oscilloscope of sorts which I can try, but swapping the unit is an easy first step. I find it hard to believe two rings corroded at the same time at the same moment I disturbed the unit I've already got replacement connectors and pins in case that's what's gone wrong in disturbing it and I just need to rewire it. Can't see how dodgy pins would cause such behaviour but I've long given up trying to second guess car electrics! Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2015 Share Posted October 30, 2015 The pins being dodgy could potentially do it. The signal changes as the speed increases so the increased pulses could degrade more as the speed increases.... eventually faulting out way before the crucial 88mph. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 30, 2015 Share Posted October 30, 2015 eventually faulting out way before the crucial 88mph. And preventing Marty from ever getting back to 1985. Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted November 21, 2015 Share Posted November 21, 2015 Hello Ian... Remember me? I haven't been on here for a heck of a long time! - Have you sorted this yet? - It looks very familiar to something I used to come across, usually on facelift cars. Quote Link to comment Share on other sites More sharing options...
Scooter Posted November 21, 2015 Share Posted November 21, 2015 Major blast from the past, hope you are well Matt. Quote Link to comment Share on other sites More sharing options...
Thorin Posted November 21, 2015 Share Posted November 21, 2015 Blimey, that is a name from the past. How you doing Matt? Quote Link to comment Share on other sites More sharing options...
Abz Posted November 21, 2015 Share Posted November 21, 2015 Hello Ian... Remember me? I haven't been on here for a heck of a long time! - Have you sorted this yet? - It looks very familiar to something I used to come across, usually on facelift cars. His waiting on me I am afraid, I have been trying to locate my RLTC at home! Quote Link to comment Share on other sites More sharing options...
RobUK Posted November 21, 2015 Share Posted November 21, 2015 I'll unplug mine and send it you Ian? I'm taking it off anyway soon to sell Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted November 22, 2015 Share Posted November 22, 2015 Hi Scott and Michael, Yeah, it's been a very long time! So much so, it almost felt nostalgic posting on here! I do pop by from time to time. I hardly recognise any of the names on here now, but I saw Ian was having a problem, which sounds very much like an issue I found when I used to fit lots of RLTC units. So I thought I'd see if I could help. Quote Link to comment Share on other sites More sharing options...
Scooter Posted November 22, 2015 Share Posted November 22, 2015 You always were helpful Are you still into your American motors? Quote Link to comment Share on other sites More sharing options...
Ian C Posted November 25, 2015 Author Share Posted November 25, 2015 I'm feeling the love here thank you Hello Ian... Remember me? I haven't been on here for a heck of a long time! - Have you sorted this yet? - It looks very familiar to something I used to come across, usually on facelift cars. Maaaaaattttt! Dude! No, not sorted yet, I've been busy with work, kids, house and home, some grotty illness and running a half marathon Plus, yeah, Abz and his filing system You got my original unit sorted back in the day, it too rattled and showed bad speed sensor readings but it also disabled the stock ABS. Obviously disturbing the unit (don't read this bit RobUK lol) caused it, just don't know if it's wiring or the unit. I don't hugely trust the Racelogic testing results yet, which brings me to... I'll unplug mine and send it you Ian? I'm taking it off anyway soon to sell That would be ace - If I had two units to test against instead of just one, and they both work I could really push it back to RLTC, and if they all go wrong in the same way then I'll be rewiring stuff sharpish (and if my unit is broken and yours works, you might sell it faster than you thought!) Quote Link to comment Share on other sites More sharing options...
RobUK Posted November 25, 2015 Share Posted November 25, 2015 Pm me your address Ian Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted November 25, 2015 Share Posted November 25, 2015 Scott, I stopped playing with American cars about 5 months ago. I've now moved to Norfolk, and working on a complete career change. my current car, (rather embarrassingly), is a Honda CR-Z hybrid! After commuting to Norfolk, it made far more sense than the Mustang did!!! Ian, can you remember what it was that we did to get your RLTC working last time? - Was it 'pull up' resistors on the ABS lines? - If so, it might be worth checking the common connection of the resistor connections, or even, (if the fronts are behaving properly), the 'legs' on the resistors themselves, as are really easy to snap if you were wiggling wires around. Quote Link to comment Share on other sites More sharing options...
Ian C Posted November 25, 2015 Author Share Posted November 25, 2015 You fixed it by swapping my rattley unit for a new one Thing is, it's been back to Racelogic who charged me £120 for the privilege of saying "it works fine", so I ideally need to test against other units first before delving deeper. Norfolk eh? Where abouts? Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted December 1, 2015 Share Posted December 1, 2015 Ahh, yes I remember the rattly unit now. I also remember the charges that Racelogic put on supposed, 'no fault found' units. Sadly, I don't have any kicking around any more. But when you do get to plug another one in, once you've set it up, if you're still seeing those spikes on the wheelspeed sensors, I would first try to fit some pull up resistors. I suggested to Racelogic, that this be built into the units years ago, as I found the problem on several cars. It was dismissed at the time though, as a redesign would be too costly, and affected such a small number of cars it wasn't worth it. I'm now living in East Ruston, not too far from North Walsham. 'Tis a strange place, where these 'North-Folk' live. Full of strange place names, spelled in ways that make absolutely no sense to the British language in their pronunciation! - Happisburgh = Hazebro, Wymondham = Windum, Hautbois = Hobbis, Costessey = Cossey... And they're just the ones near me!!! Quote Link to comment Share on other sites More sharing options...
Ian C Posted December 1, 2015 Author Share Posted December 1, 2015 If you told me what bit to solder inline where I'd be able to do that Abz's unit has been "tidied up" alas so I'm relying on Rob's unit arriving for testing now You're 22 miles away from me now Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted December 4, 2015 Share Posted December 4, 2015 I know, very local now! - I regularly pass the place in Norwich that we did a dyno day at, many years ago. I'm very much in the throws of moving, so all my old Supra docs, are 'somewhere'! Let me know when you get a chance to swap units, if that doesn't cure it, I'll make a concerted effort to dig out all my old info. Going by memory, it was a simple addition of 10k ohm resistors connected to 12v supply to buffer the ABS signal wires... Simples! Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 22, 2016 Author Share Posted January 22, 2016 I'm just going to bump this in the hope Matt has subscribed and will get a notification Speak to me Matt! Quote Link to comment Share on other sites More sharing options...
Guest JJ's TRD Posted September 17, 2016 Share Posted September 17, 2016 I'll unplug mine and send it you Ian? I'm taking it off anyway soon to sell Interested in a RLTC unit does your have the newer digital screen, i like the sound of flat shifting! Cheers Quote Link to comment Share on other sites More sharing options...
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