Temperature Gauge Sender

[JDFTVR]

The original (TVR) Temp Sender has packed in on my 450 and i propose to use the Rover sender unit fitted next to the ECU sender which is more accessible. I've been told that fitting a 150,Ohm or 200,Ohm resistor inline will bring this unit into scale with the guage. Does anyone know what the resistive scale is for each of the senders, or how the guage is scaled so i can work out a more accurate solution with resistors. Cheers.

[philmccann]

HI there

I was in touch with Caerbont gauges on the subject. This is the info supplied.

The temp sender part number is TT4803-01.
To check whether its ok or not, measure its resistance at the following temps:
1130 ohms at 40 deg C,
332 ohms at 70 deg C,
119 ohms at 100 deg C
The above resistances have a tolerance of about +/-10%.

Hope this helps

Phil

[JDFTVR]

Thats great Phil, i had visions of removing the sender and guage and testing it with ohmmeter and resistance box to calbrate it. I'll investigate what you said and put my findings back on here.

John

[GreenV8S]

philmccann said:

HI there

I was in touch with Caerbont gauges on the subject. This is the info supplied.

The temp sender part number is TT4803-01.
To check whether its ok or not, measure its resistance at the following temps:
1130 ohms at 40 deg C,
332 ohms at 70 deg C,
119 ohms at 100 deg C
The above resistances have a tolerance of about +/-10%.

Hope this helps

Phil

As luck would have it, those figures are more or less the same as the characteristics for the ECU's coolant temp sender.

[spend]

GreenV8S said:

As luck would have it, those figures are more or less the same as the characteristics for the ECU's coolant temp sender.

How does that help? I half-thought they were different threads for the various senders (but haven't checked)?

Or are you advocating en-mass Lucus ECU binning?

Dave

[Barkychoc]

Not quite the same part number - but might be worth a go for a quid.

http://cgi.ebay.co.uk/Temperature-Gauge-Transmitte...

[GreenV8S]

spend said:

GreenV8S said:

As luck would have it, those figures are more or less the same as the characteristics for the ECU's coolant temp sender.

How does that help? I half-thought they were different threads for the various senders (but haven't checked)?

Or are you advocating en-mass Lucus ECU binning?

Dave

If you have one of the cars with a 'spare' ECU coolant temp sender and a dodgy temperature gauge, it gives you an extra option.

[chimalsu]

fit a variable resistor and adjust the reading to actual temp using a laser temp gauge reading

[GreenV8S]

chimalsu said:

fit a variable resistor and adjust the reading to actual temp using a laser temp gauge reading

That would give an accurate reading at the exact temperature you calibrated it at, but what about everywhere else?

[JDFTVR]

I'd be happy with getting a good reading at 90C, and if it goes higher than that i know there is a problem and i can catch it(hopefully). The problem with putting an inline resistor is the scale is well out as the original span and zero point will shift but it's purly for general indication.

[spend]

I'm sorry but this always just sounds completely daft to me, get the sender that is matched to the gauge, or get the gauge re-calibrated to a particular sender. Is it that hard to change the sender?

I can understand jury rigging something as a temp fix, but beyond that It really worries me that people want their gauges to tell lies - is it just bragging at the Pub/H that they have particular temps/pressures that are just fictitious?

Dave

[JDFTVR]

The gauge is there primarily to warn of over temp, and is indication only. If the engine is in over heat then a 5-10c isn't going to make any difference on the gauge, but will warn you of a problem if over the normal 90c. So some reading is better than none. Yes the original sender being replaced is the ideal solution, but is very difficult and quite involved so a temporary repair, quick fix is prefered at this time. However it may be the case aswell that the difference in scaling on the TVR sender and the Rover sender is linier with the inline resistor fitted and will save us TVR V8 owners some money and provide peace of mind.

[spend]

JDFTVR said:

Yes the original sender being replaced is the ideal solution, but is very difficult and quite involved ...

Are we talking about the same sensor that just screws in the front on the manifold? Its very simple - if you don't have that big windy snake thing coiled all over the front of your engine

Dave