CwazyWabbit

Looks like it counts down from FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF James your Speedo now reads 1.0 Total It's not a simple countdown, so I need to work out how to calculate an exact figure... but for now enjoy

Current mileage is 22953.0 which is not obvious in the hex dump, will clock it on a bit and see what changes when I'm on my lunch break.

Cheers James I believe this is the post http://forums.lr4x4.com/index.php?showtopic=14892&view=findpost&p=160740

Bad earth allows the dead to rise and they start flicking your switches when you aren't looking... Or more plausibly electricity always finds the path of least resisitance, so if there is a high resistance on the normal earth point due to corrosion it may find another path via other components causing them to turn on, remember the bunched earths may have poor contact to the body and battery but good contact to each other and as a result when something is turned on that earth bundle may be raised to 12v.

1 Million read/write cycles and 40 year data retention..... so not as good as a Series 1 Speedo then

Btw I have the datasheet for the eeprom (small chip) but haven't found any details on the main chip yet... I best get on with some work now

Warning NAKED Speedometer Pictures!!!!! Once you take it apart you can see the only way to open these is to uncrimp the black metal ring ...carefully. What looks like a seam on the back of the white plastic case is just a flash mark from manufacture. PS sorry about the picture size, I was trying to leave as much detail in the first one to make it useful and then forgot to resize the second, oops... well maybe people like big chips

I soldered directly to the legs of the chip using fine wire, theory being I want to make sure it's possible first then we'll work on an easier more accessible method. The chip uses the microwire protocol which is a forerunner to SPI. I used a presto programmer I have from work to do this read but it should be possible to find something cheaper. Once I manage to power the speedo up I'll clock it on a mile or two and see what changes. Also things like resetting the trip counter may help.

If you check the reg it is a 2007 .... so maybe it squeezed in

I'll have a look this weekend and check there are crush tubes in all the holes then I'll be off shopping for some M16's at the least, thanks for your reply lrfarmer

Looks like I need to have some humble pie I think ..... I met up with James today and he rather politely pointed out that the four bolts holding my tow bar to the rear cross member are M12's and not the M16's that they are supposed to be! In my defence I didn't fit it, however I will be sorting it out before I tow anything again, I'm also going to consider adding the piece of angle iron to drop the hitch to it's correct height as James also pointed out there is a good chance there are no crush tubes on two of the bolt holes. previous owners, grrrrr

Well assuming I have my wiring correct the contents of the memory are as shown in the picture I really should have worked out how to power the speedo up first to read what the actual mileage is! Doh! Anyway it's a fairly small bit of memory I read it out by attaching directly to the chip as that three pin port looks to go to the main processor chip, I haven't traced it yet though. Middle of the 3 pins is just GND. Does anyone know the minimum amount of wires (and which ones) I need to connect to the speedo to get it to come to life? I have James' wiring diagram but unfortunately the pin numbers aren't shown on the speedo so don't know which way to count.

That might be the difference, James was kind enough to give me permission to open his speedo up so I'll be having a nose about soon, I'll post pictures when she's been laid bare

Is it possible that crcliffords speedo was done before yours Ralph? Maybe they learnt how to use the 3pin port in between doing the two? Or maybe they used his as an experiment to learn how to modify TD5 speedos, all possible I suppose.

Thanks for the offer of help on our group project Mr Freezer Sounds like we are back at school Hopefully we'll have results before you get back from Holiday... but if we don't then we may be knocking on your door!

Cheers for that info, sounds like the way I went about dismantling the VDO tacho I checked out previously. Interesting that digidash take what I would have thought is a heavy handed approach, although the back of that ring is well hidden when it's inserted back into the binnacle.

Does the seam look glued? If I can't get it apart someone mentioned there looked like a 3 pin programming port. I could connect up a logic analyser to see if I see a recognisable protocol in use and work from there, so it isn't a total disaster if I can't look inside, just means it will take longer.

I'll take you up on that offer if you are serious, I have a number of different programmers here that we use when reverse engineering at work. Not having seen a TD5 speedo close up do they look easily openable? I'd be fairly confident about not breaking it, I'll back up the eeprom contents before modifying anything so even if I fail I can return the speedo to you as it was. In fact I'll offer you the guarantee that if I break your speedo or return it in a condition you are not happy with then I will source you a replacement, would that be a deal you'd be happy with?

Bit more than that if you are running it on cherryade......

A worn clutch would slip and may smell like it's burning. How are you noticing the overheating? Via the gauge?

I'd guess the mileage is stored in either an I2C or an SPI eeprom (which is very simple to read and write to without removing from the board), I was looking for a cheap TD5 speedo to take apart so I could work out what else was stored on the eeprom. You hear stories of these being converted from MPH to KPH but keeping the same face/dial so I would guess this is also possible via the eeprom and maybe even calibration to allow for tyre size. I had hoped to work this out and post to the forum but I haven't found a cheap one yet and also I'm getting the feeling a lot of people don't want this information out there, personally I think all the dodgy people out there probably already have the information anyway. How do people on this thread feel about publishing such information?

Cheers for phoning TFL, just goes to show how badly run the whole thing is when it seems everyone is being told a different story in one way or another... If that bit is true it really is 'a bit slack'* as it's less than 6 months till it is implemented and even TFL aren't actually sure what vehicles it applies to *Replace with whichever suitable phrase springs to mind

The penalties are £100 a day! Hence why everyone is so concerned, especially as the zone comes out nearly as far as the M25. I doubt the print out would save you as it has the disclaimer on it saying they are currently updating it, although that has been there for a long while ..... obviously they aren't beating the work experience kids hard enough

That's pretty much what I was trying to say, but not very successfully, and with far too many words!

But if as you say it was a replacement engine from turners all the ancillaries will be off the original engine (which was probably a 16L) so you will have a bit of both. For example despite 21L being an EDC engine which would have an EDC injection pump you will most likely have a mechanical injection pump. So a bit of thought will still need to be applied when ordering parts and you can't blindly trust the engine numbering. Sorry if that was already obvious to you and I am teaching you to suck eggs.