I fitted a new speedometer cable to the Triumph PI - a really awkward
job, especially connecting the end behind the dashboard.

Now the temperature gauge reads high, where it used to be spot on. I
have just checked it from cold, and the needle gets over three quarters
of the way towards hot before the thermostat starts to open. I imagine
I have mucked up something electrical behind the dashboard. Any
suggestions what?

Jim

In message , Jim Warren
writes
I fitted a new speedometer cable to the Triumph PI - a really awkward
job, especially connecting the end behind the dashboard.

Now the temperature gauge reads high, where it used to be spot on. I
have just checked it from cold, and the needle gets over three quarters
of the way towards hot before the thermostat starts to open. I imagine
have mucked up something electrical behind the dashboard. Any
suggestions what?

Jim

It's possible that you might have broken the ground connection to the
instrument voltage stabiliser. In Triumphs of this age, it's a
medium-sized metal 'beetle', whose ground connection is usually to the
case of the speedo. You did re-connect the black 0V connection to the
speedo case didn't you?

--
Chris Morriss

Chris Morriss wrote:
In message , Jim Warren
writes
I fitted a new speedometer cable to the Triumph PI - a really awkward
job, especially connecting the end behind the dashboard.

Now the temperature gauge reads high, where it used to be spot on. I
have just checked it from cold, and the needle gets over three quarters
of the way towards hot before the thermostat starts to open. I imagine
have mucked up something electrical behind the dashboard. Any
suggestions what?

Jim

It's possible that you might have broken the ground connection to the
instrument voltage stabiliser. In Triumphs of this age, it's a
medium-sized metal 'beetle', whose ground connection is usually to the
case of the speedo. You did re-connect the black 0V connection to the
speedo case didn't you?


I thought I had. But I have just turned the side lights on, and the
panel lights for fuel gauge and temperature gauge light but not the
speedometer. It seems too much of a coincidence to imagine that the
bulb has blown, so my guess is that I somehow dislodged the earth.

Back to the screwdrivers and scratched hands! expletive

Thanks for the pointer.

Jim

which pi the saloon or the tr. the speedo bulb could be due to it being
dislodged from the speedo casing or just happened to pack up at the same
time. maybe the temp sender unit decided to go wrong as well. you could
check the connections on the back of the temp gauge over the years a bit of
crap and being moved could of made a dodgy connection.
dave
70 pi saloon 2000 mk1 estate
"Jim Warren" wrote in message
m...
Chris Morriss wrote:
In message , Jim Warren
writes
I fitted a new speedometer cable to the Triumph PI - a really awkward
job, especially connecting the end behind the dashboard.

Now the temperature gauge reads high, where it used to be spot on. I
have just checked it from cold, and the needle gets over three quarters
of the way towards hot before the thermostat starts to open. I imagine
have mucked up something electrical behind the dashboard. Any
suggestions what?

Jim

It's possible that you might have broken the ground connection to the
instrument voltage stabiliser. In Triumphs of this age, it's a
medium-sized metal 'beetle', whose ground connection is usually to the
case of the speedo. You did re-connect the black 0V connection to the
speedo case didn't you?


I thought I had. But I have just turned the side lights on, and the panel
lights for fuel gauge and temperature gauge light but not the speedometer.
It seems too much of a coincidence to imagine that the bulb has blown, so
my guess is that I somehow dislodged the earth.

Back to the screwdrivers and scratched hands! expletive

Thanks for the pointer.

Jim

dave wrote:
which pi the saloon or the tr. the speedo bulb could be due to it being
dislodged from the speedo casing or just happened to pack up at the same
time. maybe the temp sender unit decided to go wrong as well. you could
check the connections on the back of the temp gauge over the years a bit of
crap and being moved could of made a dodgy connection.
dave
70 pi saloon 2000 mk1 estate
"Jim Warren" wrote in message
m...
Chris Morriss wrote:
In message , Jim Warren
writes
I fitted a new speedometer cable to the Triumph PI - a really awkward
job, especially connecting the end behind the dashboard.

Now the temperature gauge reads high, where it used to be spot on. I
have just checked it from cold, and the needle gets over three quarters
of the way towards hot before the thermostat starts to open. I imagine
have mucked up something electrical behind the dashboard. Any
suggestions what?

Jim
It's possible that you might have broken the ground connection to the
instrument voltage stabiliser. In Triumphs of this age, it's a
medium-sized metal 'beetle', whose ground connection is usually to the
case of the speedo. You did re-connect the black 0V connection to the
speedo case didn't you?

I thought I had. But I have just turned the side lights on, and the panel
lights for fuel gauge and temperature gauge light but not the speedometer.
It seems too much of a coincidence to imagine that the bulb has blown, so
my guess is that I somehow dislodged the earth.

Back to the screwdrivers and scratched hands! expletive

Thanks for the pointer.

Jim


It is the Saloon

I might easily have dislodged either the bulb or the earth connection
when I had my hand behind reconnecting the trip meter cable and then
pulling the air vent tube back to its position on the back of the vent.

For the moment, I am assuming Chris's explanation is correct. Why
assume two faults when one would cause the same symptoms?

Interestingly, the old speedo cable had metal ends, the new one has
plastic. So I am beginning to wonder whether the old cable made an
earth connection from the speedo casing back to the gearbox and the new
one doesn't. It is at least as plausible as the idea of pulling a wire
off - although it is very cramped behind the dashboard, what with the
main wiring loom and air vent tubing in a small space, and it took a
good push to get my hand behind there.

Dashboard out and checks with a continuity tester, methinks.

Jim

"Jim Warren" wrote in message
m...
Interestingly, the old speedo cable had metal ends, the new one has
plastic. So I am beginning to wonder whether the old cable made an earth
connection from the speedo casing back to the gearbox and the new one
doesn't. It is at least as plausible as the idea of pulling a wire off -
although it is very cramped behind the dashboard, what with the main
wiring loom and air vent tubing in a small space, and it took a good push
to get my hand behind there.

Dashboard out and checks with a continuity tester, methinks.


Maybe the proper earth wire has been dodgy/disconnected for quite a while
and the old speedo cable was acting as an unofficial earth lead?

Ron Robinson

R N Robinson wrote:
"Jim Warren" wrote in message
m...
Interestingly, the old speedo cable had metal ends, the new one has
plastic. So I am beginning to wonder whether the old cable made an earth
connection from the speedo casing back to the gearbox and the new one
doesn't. It is at least as plausible as the idea of pulling a wire off -
although it is very cramped behind the dashboard, what with the main
wiring loom and air vent tubing in a small space, and it took a good push
to get my hand behind there.

Dashboard out and checks with a continuity tester, methinks.


Maybe the proper earth wire has been dodgy/disconnected for quite a while
and the old speedo cable was acting as an unofficial earth lead?

Ron Robinson


That was my thought too. I will check all the instrument earths while I
am at it. The rev counter panel light doesn't look as bright as I
expect either, so a dodgy earth is a distinct possibility.

Jim

Chris Morriss wrote:
In message , Jim Warren
writes
I fitted a new speedometer cable to the Triumph PI - a really awkward
job, especially connecting the end behind the dashboard.

Now the temperature gauge reads high, where it used to be spot on. I
have just checked it from cold, and the needle gets over three quarters
of the way towards hot before the thermostat starts to open. I imagine
have mucked up something electrical behind the dashboard. Any
suggestions what?

Jim

It's possible that you might have broken the ground connection to the
instrument voltage stabiliser. In Triumphs of this age, it's a
medium-sized metal 'beetle', whose ground connection is usually to the
case of the speedo. You did re-connect the black 0V connection to the
speedo case didn't you?


I thought you would like to know that your diagnosis was correct (ish).

The ground connection was apparently in place, but the spade was a very
sloppy fit and a meter across the connection showed a high resistance.
Cleaning the contacting surfaces and tightening up the grip fixed the
problem. The temperature gauge behaves normally again.

So thanks for the pointer. If I hadn't known to pay special attention
to that connection, I would have seen it in place and assumed it was OK.

The sad thing is that having got the voltage stabiliser working
properly, I have suddenly "lost" a quarter of a tank of fuel.

Jim

In message , Jim Warren
writes
Chris Morriss wrote:
In message , Jim
Warren writes
I fitted a new speedometer cable to the Triumph PI - a really
awkward job, especially connecting the end behind the dashboard.

Now the temperature gauge reads high, where it used to be spot on.
have just checked it from cold, and the needle gets over three
quarters of the way towards hot before the thermostat starts to open.
I imagine have mucked up something electrical behind the dashboard.
Any suggestions what?

Jim
It's possible that you might have broken the ground connection to
the instrument voltage stabiliser. In Triumphs of this age, it's a
medium-sized metal 'beetle', whose ground connection is usually to the
case of the speedo. You did re-connect the black 0V connection to the
case didn't you?


I thought you would like to know that your diagnosis was correct (ish).

The ground connection was apparently in place, but the spade was a very
sloppy fit and a meter across the connection showed a high resistance.
Cleaning the contacting surfaces and tightening up the grip fixed the
problem. The temperature gauge behaves normally again.

So thanks for the pointer. If I hadn't known to pay special attention
to that connection, I would have seen it in place and assumed it was OK.

The sad thing is that having got the voltage stabiliser working
properly, I have suddenly "lost" a quarter of a tank of fuel.

Jim

Glad to have been of help. I ought to have thought, the non-working
voltage stabiliser would have made the fuel gauge read high as well!
It's something that happened to me when I had a Vitesse.
--
Chris Morriss