help on faulty speedo

[corrine]

After having the pleasure of being hit from behind in my chimaera, i had the car repaired and dropped back to me, only to find that whilst driving the car home that the speedometer and mileometer no longer work?? prior to the car going in for repair they were fine.
the car is a 93 4.0 with rover gearbox and gkn (early) dif, i understand there is a speedo transducer which may be the problem but cannot locate it, am i going mad?

[Bensonv8]

Can't you take it back to the repairer and get them to sort it out ???

The Bible says,............
(Rover SD1 gearbox) The speedo is driven by a sensor on the gearbox.
or
(early T5 gearbox)From a sensor mounted above propshaft universal joint at the differential end.
or
(later cars) From a sensor close to a toothed wheel located on a drive shaft (doesn't say which one) close to the diff.

Happy hunting

Steve

[corrine]

ok i have just replaced my speedo transducer, what a pig it was to get to!(rover gearbox, early chim) and my speedo and mileometer are still not working, think i need to take toe dash top off and have the speedo looked at!!
anyone had the same problem?

[V8 Animal]

Yes my multi plug was disconnested under the tunnel
Don't understand though speedo was working prior to the accident now not working.
Did you go back to the garage?

[corrine]

to be honest no i didnt, a bit late now though, silly me!
is it speedy cables to the rescue to refurb my speedometer?

[chimalsu]

did you set the gap on the sensor correctly it has to be nearly touching the cogs set with a feeler gauge

[K4TRV]

C, What part of the car was "worked-on"??

Check your connections down near battery/ECU for a start off. Plus under the hand-brake area.

Presume you don't get the "click" every tenth of a mile, or does that work, but the speedo needle doesn't move ??

Trev

[corrine]

the speedo sensor i replaced went into the rover gearbox had teeth on it so not sure what you ment about if i need to check the gap.
K4TRV, funny you should mention the 'click' on my speedo, it always used to do that but now it doesnt!
must be my speedo unit, looks like a dash off job.

[spend]

The speed sensor on the box is only used by the Lucas Efi ECU. The sensor for your speedo is above the nose of the diff, driven by a crowned wheel at the end of the prop shaft. There is a bracket on top of the two side brackets that fix the diff in the chassis, this has the sensor. Some say you can reach up to it, I've only ever checked it with the exhaust off.

I would still do a continuity check - the connectors didn't seem great down there.

[K4TRV]

spend said:

The speed sensor on the box is only used by the Lucas Efi ECU. The sensor for your speedo is above the nose of the diff, driven by a crowned wheel at the end of the prop shaft. There is a bracket on top of the two side brackets that fix the diff in the chassis, this has the sensor. Some say you can reach up to it, I've only ever checked it with the exhaust off.

I would still do a continuity check - the connectors didn't seem great down there.

plus I expect the rear "shunt" may have displaced the sensor gap.

trev

[spend]

Hmmm, heard this gap problem before, but mine can really be anywhere between close & 1/4" and the reading is not affected. If anything it seemed more 'jerky' when set in thou's, so I backed it out to a couple of mm, and it was originally @1/4" (& OK) before I started playing?

nothing to see here you BTR or pre-cat boyos..

[V8 Animal]

Might help,
http://cgi.ebay.co.uk/TVR-Chimaera-Speedometer_W0Q...

[K4TRV]

V8 Animal said:

Might help,
http://cgi.ebay.co.uk/TVR-Chimaera-Speedometer_W0Q...

'93 speedo looks nothing like that unfortunately.

It doesn't have a "trip" meter, just total mileage.

trev

[spend]

Cheap imitations of the original eh?

[corrine]

you are a helpfull lot on here!
got to be honest i have had my chim 9 years and this is my first head scratching problem.
will have a look at the diff tonight, question though what is the purpose of the speed sensor in the gearbox then? it seems strange to have one in the gearbox and the diff?!?!

[Barkychoc]

Are you sure all chim's have the speedo driven from the diff - my V8S does use that sensor in the gearbox for both the ECU and the speedo - there's no other sensors to make it work and thats what drove the speedo on the Rover SD1 I believe.

Bensonv8 previously said:

Can't you take it back to the repairer and get them to sort it out ???

The Bible says,............
(Rover SD1 gearbox) The speedo is driven by a sensor on the gearbox.
or
(early T5 gearbox)From a sensor mounted above propshaft universal joint at the differential end.
or
(later cars) From a sensor close to a toothed wheel located on a drive shaft (doesn't say which one) close to the diff.

Happy hunting

Steve

Edited by Barkychoc on Monday 1st December 19:49

[schmokin1]

Barkychoc said:

Are you sure all chim's have the speedo driven from the diff - my V8S does use that sensor in the gearbox for both the ECU and the speedo - there's no other sensors to make it work and thats what drove the speedo on the Rover SD1 I believe.

Bensonv8 previously said:

Can't you take it back to the repairer and get them to sort it out ???

The Bible says,............
(Rover SD1 gearbox) The speedo is driven by a sensor on the gearbox.
or
(early T5 gearbox)From a sensor mounted above propshaft universal joint at the differential end.
or
(later cars) From a sensor close to a toothed wheel located on a drive shaft (doesn't say which one) close to the diff.

Happy hunting

Steve

Edited by Barkychoc on Monday 1st December 19:49

well all i can say is that on my early pre serp chim with the LT77 box I have the sensor and toothed cup thing on the nose of the diff. It's an early '94.

cheers Schmo

[spend]

Barkychoc said:

Are you sure all chim's have the speedo driven from the diff

NO, there are various configs:

Griff pre-cats just like yours.
Early cars as we have stated. (commonly LT77,GKN,ETB and cats)
Later cars with BTR drive shaft sensor & split signal to ecu when T5 box used.
There are some minor changeover period iffys I suspect but that is the gist of it.

[corrine]

ok having replaced the speedo sensor, and there being no change, i have removed the speedo unit from the dash, 2 questions
1. can anyone recomend a place that can test my speedo and confirm if its the cause of the problem.
2. there are 4 relays under the dash top panel, cannot see in the bible what they are for (2 red 1 grey 1 black) i wondered if these are linked (probably not) in any way?

[spend]

corrine said:

ok having replaced the speedo sensor, and there being no change,

You've replaced the one on the diff this time?

corrine said:

i have removed the speedo unit from the dash, 2 questions
1. can anyone recomend a place that can test my speedo and confirm if its the cause of the problem.

Early cars have ETB instruments, send them to ETB
Later cars have CAI gauges, send them to CAI / Caerbont / Speedy / Greengauges (they are all the same company )

corrine said:

2. there are 4 relays under the dash top panel, cannot see in the bible what they are for (2 red 1 grey 1 black) i wondered if these are linked (probably not) in any way?

Thats the aux relay panel, flashers , hazard relays (2), heated mirrors, heated seats.... nothing to with speedo. But there is a block connector in that area for all the instruments