Thread: D1 Speedo Transponder.Drive

I had similar problems for a while. Even got a different transponder from another car to try, still erratic behaviour. The last thing that has been working now for a good while (until I publish this probably) was to replace the standard plug near the transponder with male/female spade connectors. Its a muddy, dirty area and the old connectors had probably corroded. Seems to have worked for me, the new transponder I got from the UK is still on the shelf.

Originally Posted by Tank

ANY information on a solution or whether they are supposed to have grease in them or not would be appreciated, Regards Frank.

Hi Frank, I have had a similar problem in a Peugeot 406. Replaced the transponder, seemed to fix it, but every now and then the speedo needle flicks around. The VERY knowledgeable mechanic mentioned that, if the problem persisted, it would be worth taking the instrument cluster out and having the gauges lubricated by an instrument technician. Soon after that, the fuel gauge needle has also stuck a few times. It seems reasonable that, after 10 years or more (17-and-a-half in my Peugeot), a "sticking" needle could cause erratic behaviour. What do you think of that idea? Andrew

Hi Frank,

I'm not exactly sure how disco speed system works. But from what you are saying, I'd concentrate on bad connections. Your sensor send series of pulses to instruments and quicker the pulses more needle deflection. If you have bad connection, as connection "chatters" so to speak, your instrument reckognizes this as series of quick pulses. Hence the needle moving to maximum deflection and back as loose connection is momentarily lost.

Now there is two types of pulse speedo systems as far as I know. One would behave as I described above, other will also have crazy needle movement but never more than actual speed.

Third is, that something killing your pulses. Semi short circuit so to speak.

Hope you resolve it quickly. Let us know of the results!!!

Originally Posted by ROAMER_AUS

Hi Frank,

I'm not exactly sure how disco speed system works. But from what you are saying, I'd concentrate on bad connections. Your sensor send series of pulses to instruments and quicker the pulses more needle deflection. If you have bad connection, as connection "chatters" so to speak, your instrument reckognizes this as series of quick pulses. Hence the needle moving to maximum deflection and back as loose connection is momentarily lost.

Now there is two types of pulse speedo systems as far as I know. One would behave as I described above, other will also have crazy needle movement but never more than actual speed.

Third is, that something killing your pulses. Semi short circuit so to speak.

Hope you resolve it quickly. Let us know of the results!!!

.


Thank you all for your helpful info (there don't seem to be any "Thanks" Icon after the site shutdown), the plug was actually tied into the socket with a couple of large plastic Zip ties, right around the transfer case housing.
Has anyone ever had a look inside one of these senders, as I said mine seemed to be full of rusty grease or Never Seize copper grease, the other was dry inside, Thanks again, Regards Frank.


"Thanks" Icon is back.

Just had a look at the new transducer (sender) I have. Not going to take it apart as its new, but it sounds completely dry when I turn the spindle. There's no sign of any lubricant around the edges or anything. The old one that I had on the TDI that finally failed was also full of oily stuff, the one that is on now is out of the old V8 spares car I have and as I remember it, was dry when I had a look inside (I think, was a couple of years ago). Maybe the coppery grease you see in yours is affecting the pulse pickups?

Originally Posted by Spel1

Just had a look at the new transducer (sender) I have. Not going to take it apart as its new, but it sounds completely dry when I turn the spindle. There's no sign of any lubricant around the edges or anything. The old one that I had on the TDI that finally failed was also full of oily stuff, the one that is on now is out of the old V8 spares car I have and as I remember it, was dry when I had a look inside (I think, was a couple of years ago). Maybe the coppery grease you see in yours is affecting the pulse pickups?

Thanks Mate, it seems the only thing holding the transducer/transponder together is the Allen bolt that goes through it into the block, I'm about to attack it again today, will let you know the result, Regards Frank.

Hi Frank,

I have seen poor pin connections at the plug a few times, try a GENTLE twist of the pins in the transducer so that they slide into the female ends of the plug on a slight angle, making a better connection. The whole thing is done with a magnetic induced voltage, doesn't take much for it to lose pulses.

And yes, there is nothing inside but a rotating spindle with a ferrous insert that slips into the actual speedo gear and rotates inducing a current in the outer/ pickup in the housing. Grease is not a bad thing, but use a silicon type that won't ruin plastics etc.

JC

Originally Posted by justinc

Hi Frank,

I have seen poor pin connections at the plug a few times, try a GENTLE twist of the pins in the transducer so that they slide into the female ends of the plug on a slight angle, making a better connection. The whole thing is done with a magnetic induced voltage, doesn't take much for it to lose pulses.

And yes, there is nothing inside but a rotating spindle with a ferrous insert that slips into the actual speedo gear and rotates inducing a current in the outer/ pickup in the housing. Grease is not a bad thing, but use a silicon type that won't ruin plastics etc.

JC

Thanks all again, seems the "Thanks" icon is on the fritz again.
Would love to know who designed the splines on the front of the rear T/shaft, just long enough so as you can't remove the drum brake end. Making it only possible if you remove the rear of the T/shaft first, love to send him a note to express my feelings for him.
Both transducers had this same copper coloured grease, I cleaned the best of the 2 and clipped it back together and spun the spindle by hand, felt like a load of gravel in there. So I unclipped it and put the slightest dob of copper grease in the space where the shaft of the spinning magnet contacts, much smoother. I placed the tiniest bit of silicon gasket goop around edge and fitted back together, holding it together with a couple of small zip ties till it sets. The drive spindle in the back extension housing is rotating when I spin the rear shaft so it seems to be OK. How does that section come out of the box housing, mine has a groove in its outer edge, have tried a pry bar in the groove and a set of multi-grips to see if I could turn it, no go. Have sprayed it and will see if the mechanic fairies come round during the night and miracously loosen it up for me, or is their some weird LR trick to getting it out, while I've got it apart I will fit a new seal, I believe there is a double lip seal for the back of the T/C, anyone got a number, Regards Frank.