haunted speedo

You have indavertantly parked on four upside down roller skates?

Nice puppy mind!

In all seriousness - How odd! Mouse in the dashboard?

Lee D

Are you sure it's all cable? Or has it got a short cable at the gearbox end connected to a small genny or whatever it is? Loose wires or burnt insulation and shorting to the exhaust?

Martin

Dunno mate it is on the L reg 300 so its possible you are on the right track I assumed it was cable right through as on the early D1 its too early to have the ECM system so should it have a sensor? .Bit annoying if a spot (well quite a lot ) of coolant should be able to cause a short on a car designed to wade in 18 inches of water. Derek

Might be just coincidence it happened at the same time but mine's an 'L' reg and it's got a little box of tricks mounted on the chassis at the side of the transfer box and a short cable driving it. Then it's just wires up to the speedo. Dunno how it works though, it's never gone wrong, ooops, shouldn't have said that.

Martin

I noticed that on my 300Tdi Auto when jump-starting someone. If I revved the engine I could get the speedo to register up to about 30MPH, but I found that if I put the transfer box in neutral, it didn't do it.

Matt

I would suspect that when you drained the water some of it ran down the cable (electrical) and into the connector on the gearbox/transfer box and is shorting out a couple of pins creating a path to earth via the speedo head.

Removing the plug and drying it out will most likely cure your problem but there may be an underlying poor earth between the engine/gearbox and chassis/body that needs investigation.

Just been under and blasted plug and socket with switch cleaner but it is still doing it. With the plug removed there is no reading so either the sender is having a thromby or maybe there is an earthing issue next test is putting a meter on the sender and looking for a reading but is it variable resistance or electrical output? Derek on the bright side I remembered to bleed the clutch while I was about it.

Neither by the looks of it. The parts fiche says it's a transducer, and it also says it's a different one for coil sprung or air sprung. What's the reason for that, unless there's a static issue? Anyone?

Martin

Whatever they call it with just 2 wires it has to be one or other (resistance or electrikery)as digital is fairly unlikely IIRC the difference between a sensor/sender and a transducer is about £20 which sounds about right. what part number have you got for airsprung tho' Miles is a MA vin which I read as part YBE100540 probably one of the last 300Tdi coilers. Derek

"Derek" wrote.............

I've got no reference to that part number unless it supercedes AMR1253 which I've got for MA081992 onwards which fits direct to the transfer box. The earlier one driven by a short cable and fastened to the gearbox mounting point is up to LA081991 and part no. PRC5956. Ignore that air suspension alternative, it was for the RRC and is AMR3386.

Martin

Spot on mate I googled the part number and it is a replacement for amr1253 interesting that it is also used on the EFi models as part of the engine management system. I'll give it a day ot two in case the gremlins get bored before I look for a replacement . Derek

The output from the sensor is a simple square wave, the frequency of which increases with speed. This makes checking it's resistance/impedance both awkward and pretty pointless. You could try shorting out the pins in the cable going to the sensor and see what happens.

This is from the electrical trouble shooting manual for a 1995 Discovery:

HTH :-)

PS: If you need the circuit diagram just let me know, but I still think it's an earth problem :-)

Bearing in mind Miles is a 94 pre ECM yes I would like a squint at the circuit diagram. I just tried earthing the transfer case to the battery neg but that made no difference its still swinging about above 30 I think. I can discount a wet in the wiring issue the leak would have been hard pressed to reach the sensor or plug which are tight in between the transfer case and the transmission brake drum. It looks more and more like the transducer is at fault .wonder if anybody has one on a breaker? Derek

Bearing in mind Miles is a 94 pre ECM yes I would like a squint at the circuit diagram. I just tried earthing the transfer case to the battery neg but that made no difference its still swinging about above 30 I think. I can discount a wet in the wiring issue the leak would have been hard pressed to reach the sensor or plug which are tight in between the transfer case and the transmission brake drum. It looks more and more like the transducer is at fault .wonder if anybody has one on a breaker?

Derek (if anybody gets mulitple posts my apologies Virgin appear to be screwing around with group posts- this is a repeat of a message posted over an hour ago that just vanished)

Bearing in mind Miles is a 94 pre ECM yes I would like a squint at the circuit diagram. I just tried earthing the transfer case to the battery neg but that made no difference its still swinging about above 30 I think. I can discount a wet in the wiring issue the leak would have been hard pressed to reach the sensor or plug which are tight in between the transfer case and the transmission brake drum. It looks more and more like the transducer is at fault .wonder if anybody has one on a breaker? Derek (this is the third attempt to post this response which proves you can screw folk and still be a Virgin ----media)

Bearing in mind Miles is a 94 pre ECM yes I would like a squint at the circuit diagram. I just tried earthing the transfer case to the battery neg but that made no difference its still swinging about above 30 I think. I can discount a 'wet in the wiring issue' the leak would have been hard pressed to reach the sensor or plug which are tight in between the transfer case and the transmission brake drum. I was thinking transducer fault but logic is kicking in and I think it may be a fault on the speedo circuit board bloody sat nav is going in for the time being

Derek (this is the forth attempt to post this response which proves you can screw folk and still be a Virgin ----media)

Derek,

Sorry but don't have the manuals for 1994 but if you let me have your email address (mung it obviously) then I'll happily send you the 95 diagrams.

its on there Steve just remove the Police / spiced meat reference

You have mail, :-)