Temp gauge not working

[rickprice]

Folks, can anyone help?

My temperature gauge is not working. I have checked the fluid level and its all OK so no immediate panic, per se.

I have a 2000 Chimaera with the Serp engine.

Under the dash looks OK - all connections present and correct.

Do I just need a new sender, and if so which one, from where in the engine?

Many thanks,

Richard

[bobfather]

Take the opportunity to do the Rover coolant temperature mod. Far quicker response and located next to the ECU temperature sender so the dash gauge shows the same temperature as the ECU is responding to.

Loads of threads on this subject, here's one

https://www.pistonheads.com/gassing/topic.asp?t=11...

[GR_TVR]

As above.
I'd change the sensor as well - I picked up a new one on eBay for £3.85 delivered!

[rickprice]

Can I ask which sensor?

[GR_TVR]

Sure - here it is http://www.ebay.co.uk/itm/370890433656

£3.20 delivered and mine works perfectly.

Don't forget you will need to add a resistor and bullet connector onto the existing spade connector to use this sensor. I think the info is in the thread above.

[rickprice]

Which resistor did you get - not wanted to sound like a numpty but Maplin couldn't help and suggested amazon!

Rich

[bobfather]

It's around 130 ohms. I fitted a link that allowed an adjustment between 100 and 200 ohms. I used to sell them here but I don't have any stock left. I would suggest you go to ebay where you can find an ample supply of very cheap resistors. I'd suggest you fit a 130 ohm greater than 1W resistor

http://www.ebay.co.uk/itm/130-Ohm-3W-Metal-Film-Re...

[rickprice]

Many thanks.

Richard

[john hamblett]

Just done this mod on mine maplins do have what you want but you need to ask for a 0-200 ohm potentiometer use the middle on and either of the two outer pins and adjust as required
Mine ended up at around 160 ohms temp gauge now reads correctly

[Alpha Omega]

I think it will be worth your while in proving what the fault is before modifying anything
Short the sender wire to the engine and check if the gauge moves to hot, if the gauge doesn't move it isn't going to move after you modify the circuit, you will need to check the wiring from the sender to the gauge and if that is ok you will need to check the supply to the gauge and if that is ok the gauge will be faulty
Once you have the gauge working you can then carry out the modification
There is little point in modifying anything that isn't working and has an unknown fault
Prove what the fault is then modify when all needed parts are at your door

[bobfather]

Alpha Omega said:

I think it will be worth your while in proving what the fault is before modifying anything
Short the sender wire to the engine and check if the gauge moves to hot, if the gauge doesn't move it isn't going to move after you modify the circuit, you will need to check the wiring from the sender to the gauge and if that is ok you will need to check the supply to the gauge and if that is ok the gauge will be faulty
Once you have the gauge working you can then carry out the modification
There is little point in modifying anything that isn't working and has an unknown fault
Prove what the fault is then modify when all needed parts are at your door

Makes sense in principle but the TVR sender is located in a very poor position, a dead space in the coolant flow and due to the extended pipe fitting it is subject to air cooling. The ECU coolant temperature and the gauge temperature from the Rover sender start to rise in less than a mile and reach stable hot temperature after 6 miles. On mine the TVR sender didn't even move for 5 miles and while the car was in motion it read significantly lower than the ECU reading, only matching it when I got stuck in traffic. I put that down to air cooling

[Alpha Omega]

bobfather said:

Alpha Omega said:

I think it will be worth your while in proving what the fault is before modifying anything
Short the sender wire to the engine and check if the gauge moves to hot, if the gauge doesn't move it isn't going to move after you modify the circuit, you will need to check the wiring from the sender to the gauge and if that is ok you will need to check the supply to the gauge and if that is ok the gauge will be faulty
Once you have the gauge working you can then carry out the modification
There is little point in modifying anything that isn't working and has an unknown fault
Prove what the fault is then modify when all needed parts are at your door

Makes sense in principle but the TVR sender is located in a very poor position, a dead space in the coolant flow and due to the extended pipe fitting it is subject to air cooling. The ECU coolant temperature and the gauge temperature from the Rover sender start to rise in less than a mile and reach stable hot temperature after 6 miles. On mine the TVR sender didn't even move for 5 miles and while the car was in motion it read significantly lower than the ECU reading, only matching it when I got stuck in traffic. I put that down to air cooling

You must have misunderstood something
Everything I have typed above is all logic and does make sense
The OP must be sure that the circuit does work before carrying out a modification
Air or no air in the system has nothing to do with what information I have posted
When a temperature gauge fails, the first test is to prove that the electrical circuit is working correctly, this is the only logical way of proving anything before getting involved with any other work
Should the gauge work when shorting the sensor wire to ground, then and only then should the OP be delving deeper

I hope this helps increase your knowledge

Edited by Alpha Omega on Friday 9th June 11:58

[bobfather]

Alpha Omega said:

Air or no air in the system has nothing to do with what information I have posted

Where did I mention air in system, my comment about air cooling refers to ambient air passing over the exposed parts of the TVR sender and its extension pipe.

My understanding of this issue is fine, the TVR sender is poorly located and therefore carrying out the Rover sender mod make sense. I agree that the circuit should be tested to prove the gauge and wiring is sound but taking the opportunity to improve the system also makes sense. I have carried this mod out on 14 cars now I do feel confident in my level of knowledge.

Thank you for your concern

[Alpha Omega]

bobfather said:

Alpha Omega said:

Air or no air in the system has nothing to do with what information I have posted

Where did I mention air in system, my comment about air cooling refers to ambient air passing over the exposed parts of the TVR sender and its extension pipe.

My understanding of this issue is fine, the TVR sender is poorly located and therefore carrying out the Rover sender mod make sense. I agree that the circuit should be tested to prove the gauge and wiring is sound but taking the opportunity to improve the system also makes sense. I have carried this mod out on 14 cars now I do feel confident in my level of knowledge.

Thank you for your concern

I know you didn't mention air in the system, I edited my post to remove this from one line but missed it in another line.

This is definitely going nowhere is it
Not once have I questioned the benefits of a modification
I haven't even questioned your knowledge about a misunderstanding of a modification
I have mentioned that you must have misunderstood my earlier post regarding verifying the temperature gauge circuit is working correctly before going any further

You in reply to my above advice mentioned Makes sense in principle but the TVR sender is located in a very poor position

Now to me this sure does look like you misunderstood my post

In your latest post you mention I agree that the circuit should be tested to prove the gauge and wiring is sound

Now my way of reading into your comments are as follows. I post good logical advice in pointing someone in the right direction
You comment about my advice - Makes sense in principle but the TVR sender is located in a very poor position
You later comment - I agree that the circuit should be tested to prove the gauge and wiring is sound

I have no idea what has bothered you about me posting good logical advice that has been overlooked by others

My apologies for the bad editing of my post where I mention air in the system

Edited by Alpha Omega on Friday 9th June 13:05

[rickprice]

OK folks, let it go.


I understand both points of view;

1. Make sure it really is the sensor
2. Move the sensor regardless

I get both and thanks for the advice - it is well received.

Rich

[bobfather]

Alpha Omega said:

I have no idea what has bothered you about me posting good logical advice that has been overlooked by others

It was the the belittling comment "I hope this helps increase your knowledge". As if to suggest my knowledge was poor

Over to you to have the last word