E200JVV GTA TURBO Resto

Okay Dokey John, not guilty on sensor connector as it was chopped off and hard wired then wrapped in a Mr Kiplings foil pie case ( mince pie by the taste of it ) by previous parties unknown

I think that's the case on a fair few cars out there Ryan. People struggled with this issue for a long time and there were various trains of thought as to where the signal was dropping out. Multiplug style connection near the wheel arch was an obvious source of problems, hence garages and individuals trying to fix the issue by hardwiring.

Ryan ,pop down and we can see what;s what .I have 'chopped' sensors and clocks for test purposes .My recent digging would suggest that the sensors are quite robust and rarely fail .I spent a couple of days faffing only for it all to suddenly come to life and still working afaik .

Will do Lee, ta very much, I'll give you a bell later this week as I need to know if you are Knutsford bound Sunday as well.
Think I wee wee'd the French wiring gremlins off as some have escaped and attacked my angle grinder ( now dead ) washing machine now only cold washes, printer decided it doesn't like it's cartridges and the wi fi is acting up..............so I'm gonna back right off and chill, 'cos it's got to the slammin' doors and stomping about phase................. ................ .......
On the plus side I've got a jack plug to go in the head unit.......but I daren't .....not yet.......

sent you an email about Sunday .Longdrop needs to know table settings .......

As I was passing my Friendly Renault Garage this morning, I decided to check to see if Renault was still able to supply the speed sensor for these Alps ..... and guess what .... They tell me that, although not available in England, they are still listed in France at around £113. But they are quite confident that they are still available..... possibly with the round connector fitted, but that is not a problem.
That being said .... and following Lee's comment ... "My recent digging would suggest that the sensors are quite robust and rarely fail" .... this is exactly the same view as I have held and posted in the past. However, my thinking has changed. The reasoning for this is.
Having done a resistance check on my speed sensor and come up with a reading of 1.6 ohms for a known good one, Looking back on Lee's readings of 2.7 to 3 ohms, and Ryan's of 2 Ohms ....... It occurs to me that they have a tendency, over usage and time, to seem to go high resistance. Now as these items are made in mass production, it is the amount of wire used (length) that sets the resistance.
I just cannot see that the in production, up to nearly twice the amount of wire is wound around these magnetic cores. I would suggest that probably, say, 2-3% tolerance could be accepted in production .... even then that could amount to quite a numbers of meters of extra wire. Somehow, I don't think so.
Which brings me to these higher resistance sensors. Now I do know that the speedo boards require as a minimum, 0.55v of signal, anything below that level, the speedo stops working. Also, this type of sensor does not generate big voltages, so any high resistance in the circuit will, at some stage, cause the voltage not be high enough to trigger the speedo board.
We know that I can get the speedo to work with 0.55v of sine wave ..... which incidentally is the same level as 3 other speedo boards I have tested. So I am sure the only way forward now, is to fit a new sensor. Trying old sensors, to me now, is not the way forward ..... although I have advocated that before. If I am right and they are indeed ageing, we might be putting other insensitive sensors in, and getting the same result as we have now.
Going on other comments about the club holding known good items for test purposes, perhaps Lee would be the best positioned to hold such a component for testing suspect sensors if the club agreed to fund the item.
Any comments would be appreciated.

John

PS. Of course, the other thing I forgot to say is that with ageing, the magnetic core of the sensor could also loose some of its magnetism and as a consequence, that would also reduce the pulse voltage.

hmmm ,yes ,very early sensors on that last lot .I do have 3 610s in atm so can do a quick test on them and see what we get resistance wise

That would be a great help Lee .... Thanks.

.

Not so easy to send you them from the 610s as the sensor is in the loom ,all goes to multiplug

.

Despite more JohnC guided speedo fiddlisations still no speedo,...........but I'm close .........might nit up to the Ferrari P4 rep owners house and 'borrow' his speedo sensor
On the upside I now have ipod connectivity thanks to Dave Williams and Jon V info but I have put the jack in the ash tray as I couldn't be bothered with the dremmel bit on the stereo, .....can't wait to get some BeeGees on

You're a man clearly in need of the Bee Gees Kit:

https://www.youtube.com/watch?v=XYaymcp2YlE

Still quite puzzled about this speedo problem, but today I thought I would see if there was a simple DIY way to check these sensors on the car with an LED plugged directly into the sensors connector in the engine compartment. So with the off side wheel off the ground and the LED connected to the connector there was no indication when the wheel was turned by hand. It was just a longshot, but worth trying. Clearly, although there is a pulse when the wheel is turned, it has insufficient power to trigger the LED.
However, something I had not noticed before although I did know that the speedo board input is polarity concious, I had not realised that in order to achieve this, the wire colours (Red & White) have to be crossed in the connector, ie:- Red to White & White to Red. I have attached a pic which shows the cross colour wiring ..... it isn't a good pic, but it is not too easy to get to on the Atmo with a camera.
I remember Andrew (turbodog) has posted in the past that the TDC sensor has to be cross wired on replacement ...... this seems to be French Wiring Logic.
I have had Ryan try crossing these Red & White wires, as he had told me that when he had replaced the connector, he had wired Red to Red & White to White .... I got quite excited at the time, but still nothing. I then said to him that he would have to consider swapping the colours each time he did a test with a sensor as I was none too sure (then) which way round was correct. . ...... but now we know.
Here is the pic:-



The quest goes on

Slightly off on a tangent...but related to speedo woes..
Anyone used one of these...or similar...a scope/signal generator that you connect to a tablet...
https://www.lab-nation.com
Looks like just the thing to hook up to speedo sensors..or test the clocks by generating the required signal..maybe a bit too fancy pants for our needs...
Almost at a price you could justify to save the time farting about fixing this stuff.

Mmmmm spotted them scope things for laptops and also the little atom thingies, still not sure where to go on this, I really want to get a signal or not, then know to get a new sensor. But if I invest in some sort of scope whether it's £50 or £120, and I find I do have the right signal then what, and if I don't I'll have to buy a sensor as well anyway.
I can wait and take the car to Lees when I am taxed in the spring and we can try different sensors and may well end up doing that, but John has spent considerable time with me going through everything methodically, he testing my speedo board, me testing the speedo head plus various other connector cleaning, checking and lots of readings taken at various points in a bid to nail it down and hopefully add to the method of repair that may benefit others.
If the speedo head and board are tested and proved OK (with the correct power and earth provided) it can only be down to a signal issue.
A length of screened twin cable gaffer taped to the roof and through the window direct to the board, then either a new or known working sensor will I think be my next plan of attack.
I had started to think along the lines of whether there is a mechanical issue with whatever the sensor takes its pick up from, bearing in mind air gaps with CAS sensors ( wear in diff bearings...expansion...?), but I know nothing of the gearbox end...........so I dunno' ...?
As I have said to John in the big scheme of things it's no biggy, more wanting to know why and how to sort it, rather than .....they all do that sir, ......try driving it on Tuesdays instead of Sundays with one window down.....