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1985 TVR 350i, stabilised voltage for instruments?

Posted: Mon Sep 19, 2022 1:48 pm
by Fed_up_Stag-owner
Greetings all

I'm waking up my TVR 350i (RV8 with flapper) after a long rest, the temperature gauge isn't working but the fuel gauge is (both VDO gauges). The single wire to the temperature gauge sensor in the block measures as 7v when disconnected from the sensor (this isn't the temperature sensor for the ECU or the temperature sensor for the 9th injector). If I ground the wire the gauge doesn't move

What is the stabilised voltage for instruments on a TVR 350i? My guess is 10v.

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I'm using this useful diagram as posted elsewhere on this forum:

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Re: 1985 TVR 350i, stabilised voltage for instruments?

Posted: Tue Sep 20, 2022 9:12 am
by DaveEFI
Did you ground the sensor for some time? Hotwire gauges move slowly.
BTW, I've redrawn the Vitesse wiring diagram in colour, which makes it easier to follow a circuit. If you'd like it PM me with an email address and I'll send the PDF.
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Re: 1985 TVR 350i, stabilised voltage for instruments?

Posted: Wed Sep 21, 2022 6:39 am
by Fed_up_Stag-owner
">Did you ground the sensor for some time? Hotwire gauges move slowly. <"

Probably grounded for a couple of minutes, so I'll re-visit that.

Thanks for the offer of the revised drawing, PM on the way to you

Re: 1985 TVR 350i, stabilised voltage for instruments?

Posted: Thu Sep 22, 2022 3:54 pm
by Fed_up_Stag-owner
To update this, the wire from the gauge to the sensor must be damaged, I've grounded the output terminal from the gauge and seen full scale deflection, I've also temporarily run a wire from the output terminal of the gauge over the windscreen and connected to the sensor, the gauge works although appears to be reading a bit high.

Is there any production car where the dashboard and gauges are designed to be removed easily? I'm far too old (and fat!) to get into the footwell to work upside down.

Re: 1985 TVR 350i, stabilised voltage for instruments?

Posted: Fri Sep 23, 2022 9:04 am
by DaveEFI
The SD1 has the instruments in a pod which can be removed fairly easily. A PCB connects all the instruments, and the harness plugs into that.
BTW, if you've sent me a PM, I've not received it.

Re: 1985 TVR 350i, stabilised voltage for instruments?

Posted: Fri Sep 23, 2022 2:37 pm
by ChrisJC
Most modern cars can have the instruments removed easily, from the drivers seat. But you end up with an electronic instrument cluster! Not much use to anybody.

Chris.

Re: 1985 TVR 350i, stabilised voltage for instruments?

Posted: Fri Sep 23, 2022 5:06 pm
by Fed_up_Stag-owner
@ DaveEFI, I don't know what I did with the previous PM, but it's not in my sent box, another PM sent to you which is stuck in the PM outbox

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I think I have your email address somewhere

@ChrisJC

I would prefer a dashboard that is designed for good access for trouble-shooting and repairing, most car buyers and most car manufacturer's probably prefer sleek looks with no visible fixings. More slack on the cables would be useful, although this would create additional manufacturing costs, and I doubt if any car manufacturer had or has any interest in assisting trouble-shooting 40 years after manufacture.

At least my TVR has colour-coded cables, early TVRs did use a colour coding of some sort: all black.