Temperature Gauge and Sender (Again)
Discussion
My temperature gauge has been acting up for a while. The fans seem to kick in without any trouble and the car is driving OK so it hasn't worried me too much as having read a few threads on here a failed sender seems to be a common fault.
I took a look at it this morning. I disconnected the connector on the spade and shorted it out. The temp gauge went up to maximum so I'm definitely inclined to think it's the sender.
Having read a few of the posts on this I'm thinking of moving the sender to the "Rover" hole but want to check a few things first.
I have pinched these pictures from user 977 on a different thread as they are helpful (hope that is OK )
This is the type of gauge I have - is this Caerbont ??
This is the same as my engine bay
I am currently connected to the spade connector (original TVR) down in the centre of the picture.
The browny / bronze plastic block connector is for the ECU ??
The stick up spike by the corner of the block is the Rover connector ??
Uncle Fester wrote about a thread adaptor and a correct sender to utilise the Rover hole.
Can someone please tell me what size adapter and sender I need for the Rover hole and where I might get these from.
Thanks
I took a look at it this morning. I disconnected the connector on the spade and shorted it out. The temp gauge went up to maximum so I'm definitely inclined to think it's the sender.
Having read a few of the posts on this I'm thinking of moving the sender to the "Rover" hole but want to check a few things first.
I have pinched these pictures from user 977 on a different thread as they are helpful (hope that is OK )
This is the type of gauge I have - is this Caerbont ??
This is the same as my engine bay
I am currently connected to the spade connector (original TVR) down in the centre of the picture.
The browny / bronze plastic block connector is for the ECU ??
The stick up spike by the corner of the block is the Rover connector ??
Uncle Fester wrote about a thread adaptor and a correct sender to utilise the Rover hole.
Can someone please tell me what size adapter and sender I need for the Rover hole and where I might get these from.
Thanks
Edited for spooling and mistopys
Edited by over_the_hill on Friday 4th December 22:17
just call these guys
http://www.tvrshop.com/product-section.asp?MakeID=...
the cars with the black bezels use a different sender.
http://www.tvrshop.com/product-section.asp?MakeID=...
the cars with the black bezels use a different sender.
Its not the same as Festers IIRC, as Fester has the same manifold but different gauges. I can have a look tomorrow what the thread is if you can't find it, but the adapter to 1/4"NPT should be available (that is the most common sensor size) from just about anywhere - I'd be surprised if you can't get one from CAI along with a new sensor.
Hi there
Just changed mine over to the RR sender. My problem was that the gauge is out of calibration. How do I know this?, 'cos I "borrowed" a precision resistance box from work (along with a barrowload of various resistors) and tested it. Using the original sender, to correct for the gauge calibration, I would need to have applied LESS resistance in the loop to get the circuit to read right. Obviously this is not possible. So bought a brand new RR sender, carried out resistance v temp reading tests on it, in a pot in the kitchen with a multimeter. Doesn't need to be mega accurate. When I got a sender from Caerbont gauges, during my initial investigations, even they say a tolerance of +- 10% is inherent. Needed to apply a resistor of 150 Ohms to the loop to get the RR sender v gauge calibration correct, and it has never read better since I've had it.
The RR sender is in a far better position to read temperature anyway. The original is in an adaptor creating a sort of "dead" leg where there is little or no water flow.In past investigations I broke the brass adaptor which the original sender screw into. Got a guy to make me one in stainless at work, but when all fitted with the sender there is very little room in the adaptor for any water to get around.So this in itself is far from ideal.
The original set up would never get above ~50DegC when the engine was most obviously above that, and would take an age to even get to there. I have the David Beers Twin temp fan thingy fitted so was confident that all was ok in that department. But always pee'd me off that it didn't read correctly. All sorted now though. Gauge reacts much quicker and is always reading a sensible temperature.
HTH
Phil
Just changed mine over to the RR sender. My problem was that the gauge is out of calibration. How do I know this?, 'cos I "borrowed" a precision resistance box from work (along with a barrowload of various resistors) and tested it. Using the original sender, to correct for the gauge calibration, I would need to have applied LESS resistance in the loop to get the circuit to read right. Obviously this is not possible. So bought a brand new RR sender, carried out resistance v temp reading tests on it, in a pot in the kitchen with a multimeter. Doesn't need to be mega accurate. When I got a sender from Caerbont gauges, during my initial investigations, even they say a tolerance of +- 10% is inherent. Needed to apply a resistor of 150 Ohms to the loop to get the RR sender v gauge calibration correct, and it has never read better since I've had it.
The RR sender is in a far better position to read temperature anyway. The original is in an adaptor creating a sort of "dead" leg where there is little or no water flow.In past investigations I broke the brass adaptor which the original sender screw into. Got a guy to make me one in stainless at work, but when all fitted with the sender there is very little room in the adaptor for any water to get around.So this in itself is far from ideal.
The original set up would never get above ~50DegC when the engine was most obviously above that, and would take an age to even get to there. I have the David Beers Twin temp fan thingy fitted so was confident that all was ok in that department. But always pee'd me off that it didn't read correctly. All sorted now though. Gauge reacts much quicker and is always reading a sensible temperature.
HTH
Phil
From this thread: http://www.pistonheads.com/gassing/topic.asp?h=0&a...
These were fitted to loads of different Ford models from the 1960’s onwards. The last car to have this type was the Granada that finished production in the early 90’s.
They can be fitted into the hole for the original Rover sender with the use of an adaptor. ETB instruments sell the sender for £10 and the adaptor is about couple of quid.
This produces accurate and stable readings across the whole temperature range, yet responds immediately to real changes. All verified by cross checking the gauge reading against an optical thermometer and the output from the ECU temperature sender, which I can read via the Emerald ECU.But it doesn't sount like the ford sender will work with later gauges. Is it possible to use an adaptor to locate the original later TVR sender in the rover senders position?
Edit: ETB Instruments link... http://www.etbinstruments.com/
Uncle Fester said:
locodude said:
I believe that it is calibrated specially for the TVR gauges (2 types I believe)
I have no idea about the later gauges, but the correct sender for the gauges in my 1994 (digital odometer type) is an early Ford. These gauges wern't made by Ford, but were made to match Ford gauges electrical resistance profile so that Ford senders could be used.These were fitted to loads of different Ford models from the 1960’s onwards. The last car to have this type was the Granada that finished production in the early 90’s.
They can be fitted into the hole for the original Rover sender with the use of an adaptor. ETB instruments sell the sender for £10 and the adaptor is about couple of quid.
This produces accurate and stable readings across the whole temperature range, yet responds immediately to real changes. All verified by cross checking the gauge reading against an optical thermometer and the output from the ECU temperature sender, which I can read via the Emerald ECU.
Edit: ETB Instruments link... http://www.etbinstruments.com/
Edited by JaySTee on Saturday 5th December 11:45
Another useful thread - http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Uncle Fester said:
The cure is to obtain a temperature gauge sender that’s electronically matched to the gauge, and then fit it in the water flow.
The Original TVR sensor matches the gauge electronically, but is in an unsuitable position. The Rover sensor is in a suitable position, but is electronically unmatched.
The cure is to obtain a correct sensor and fit it with a thread adaptor in the coolant flow. Early TVR gauges were electronically matched to early Ford senders. I don’t know about the later gauges.
Once you do this simple modification, you find the car warms quickly to about 70C after a mile. It then runs 85-90C at all times if everything is right with the cooling system, dependant on ambient temperature. This is with Emerald controlled fans. Each fans switch's on and off at a different temperature.
There is complete agreement between ECU temperature sender output (Emerald ECU live reading), optical thermometer readings and the new sender.
Here’s where the new sender goes.
Uncle Fester - Hope you don't me me quoting your posts off the other threads The Original TVR sensor matches the gauge electronically, but is in an unsuitable position. The Rover sensor is in a suitable position, but is electronically unmatched.
The cure is to obtain a correct sensor and fit it with a thread adaptor in the coolant flow. Early TVR gauges were electronically matched to early Ford senders. I don’t know about the later gauges.
Once you do this simple modification, you find the car warms quickly to about 70C after a mile. It then runs 85-90C at all times if everything is right with the cooling system, dependant on ambient temperature. This is with Emerald controlled fans. Each fans switch's on and off at a different temperature.
There is complete agreement between ECU temperature sender output (Emerald ECU live reading), optical thermometer readings and the new sender.
Here’s where the new sender goes.
Ahh just found a better one see below, so if you fancy taking your gauge out and sending it to speedy cables they will test a sender with it that should fit in the Rover hole and send them both back to you for a small fee. If anyone has done this already with the later gauges it would be good to know.
BTW I wouldn't normally do all this searching and pasting but I am having a very dull saturday at work and also would like to get my temp gauge working better
From http://www.pistonheads.com/gassing/topic.asp?h=0&a...
BTW I wouldn't normally do all this searching and pasting but I am having a very dull saturday at work and also would like to get my temp gauge working better
From http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Uncle Fester said:
I don’t have a photo to hand, has anyone else got one handy they could post?
The Rover sender is forward and towards the middle of the engine by a couple of inches from the TVR sender.
Which sender and therefore adaptor you require depends upon which instruments are fitted to your car. I did the research to find out what I needed, but didn’t research all the instrument options fitted.
Essentially, senders are relatively expensive to tool up and make unless you make large quantities. Therefore car makers settle upon a design and use it across many models and years.
Aftermarket instrument makers design their products to be compatible with an existing sender from a major manufacturer.
I have a 1994 Griffith 500. The instruments have a digital odometer. This type used the early Ford temperature gauge sender. This type was fitted to almost every European Ford car between the 1960’s and the Granada version that finished in the early 1990’s. My type of instruments is now serviced by ETB.
Your car will almost certainly have different instruments to mine. I’m guessing yours are made by CAI. These are now serviced by a company called www.Speedycables.com
I think you need an adaptor with an internal or female 1/8NPT thread. External thread 5/8 X 18 UNF The speedycables part number is TE7.
I just gave them a quick phone call.
Tt3001-8n is their part number they think you will need for the sender, but to be 100% certain, they need someone to send them a temperature gauge, just in case TVR fitted something odd. They can then measure the requirements of the gauge and supply the correctly matched sender. Mark it for the attention of Andy. The temperature gauge hardly ever goes wrong, so he doesn’t have one in for service.
Does anyone already have their dash apart and wouldn’t mind sending the temp gauge? Perhaps you have a faulty speedo that you were going to send in anyway and could add your temp gauge for everyone’s benefit please. As I said mine is the other type, so I can’t do it myself.
Once this is established everyone with CAI instruments can have a truly accurate temperature gauge. Having made this modification on mine, I now have complete agreement between the temperature gauge reading and the ECU sender reading. I have an Emerald ECU, so can read this on my laptop. Both of these are validated with an optical thermometer. The extra peace of mind and protection for the engine is well worth it.
The Rover sender is forward and towards the middle of the engine by a couple of inches from the TVR sender.
Which sender and therefore adaptor you require depends upon which instruments are fitted to your car. I did the research to find out what I needed, but didn’t research all the instrument options fitted.
Essentially, senders are relatively expensive to tool up and make unless you make large quantities. Therefore car makers settle upon a design and use it across many models and years.
Aftermarket instrument makers design their products to be compatible with an existing sender from a major manufacturer.
I have a 1994 Griffith 500. The instruments have a digital odometer. This type used the early Ford temperature gauge sender. This type was fitted to almost every European Ford car between the 1960’s and the Granada version that finished in the early 1990’s. My type of instruments is now serviced by ETB.
Your car will almost certainly have different instruments to mine. I’m guessing yours are made by CAI. These are now serviced by a company called www.Speedycables.com
I think you need an adaptor with an internal or female 1/8NPT thread. External thread 5/8 X 18 UNF The speedycables part number is TE7.
I just gave them a quick phone call.
Tt3001-8n is their part number they think you will need for the sender, but to be 100% certain, they need someone to send them a temperature gauge, just in case TVR fitted something odd. They can then measure the requirements of the gauge and supply the correctly matched sender. Mark it for the attention of Andy. The temperature gauge hardly ever goes wrong, so he doesn’t have one in for service.
Does anyone already have their dash apart and wouldn’t mind sending the temp gauge? Perhaps you have a faulty speedo that you were going to send in anyway and could add your temp gauge for everyone’s benefit please. As I said mine is the other type, so I can’t do it myself.
Once this is established everyone with CAI instruments can have a truly accurate temperature gauge. Having made this modification on mine, I now have complete agreement between the temperature gauge reading and the ECU sender reading. I have an Emerald ECU, so can read this on my laptop. Both of these are validated with an optical thermometer. The extra peace of mind and protection for the engine is well worth it.
Uncle Fester said:
There is complete agreement between ECU temperature sender output (Emerald ECU live reading), optical thermometer readings and the new sender.
Don't be fooled into thinking that the gauge has become more accurate just because both sensors are now adjacent to each other...It is only the coolant temp at that exact spot in its circulatory journey - heating & cooling all the way round....
Also, be aware that, as in my case, the gauge itself could be out of cal, and therefore no new sender will correct it. As said before the original sender is now useless to me and I am running on a modified RR sender.
Replacing the gauge would certainly help a lot, but can't be ar**d.
So modified RR it is, and happy with it.
Cheers
Phil
Replacing the gauge would certainly help a lot, but can't be ar**d.
So modified RR it is, and happy with it.
Cheers
Phil
lotusandy said:
over the hill, did you get anywhere with this is in the end?Andy
I've been a bit busy this week so haven't had chance to look into it any further.But I'm still a bit confused. If I get an original TVR sender matched to the CAI gauge as I have now - the bit lower down in the picture, get and adaptor for the Rover hole, remove the RR sender (pointy bit by corner of brown plastic block) stick adaptor in RR hole, stick TVR sender into adaptor and reconnect to the gauge, everything should just work - Yes / No ??
Just get a CAI/Greengauges/speedy... sender they use a standard calibration (just happens that the earlier ETB use a different standard Smiths vs VDO IIRC - I'll avoid mentioning Stewart Warner as they were not used on Chims).
Most of the senders will be a fine NPT thread which are an engineering wide standard - so the adapters will be interchangeable / sourced from anywhere, but the electrical characteristics of the sender used must be matched to your gauge. Later TVR instruments are all CAI, check Caerbont Auto Ind and you will see all the bits of the SAME company (which may be what is confusing you?).
Most of the senders will be a fine NPT thread which are an engineering wide standard - so the adapters will be interchangeable / sourced from anywhere, but the electrical characteristics of the sender used must be matched to your gauge. Later TVR instruments are all CAI, check Caerbont Auto Ind and you will see all the bits of the SAME company (which may be what is confusing you?).
has anyone bottomed this out yet?
sounds like a "standard" CAI sender (same as TVR N0125 or http://www.powerstores.co.uk/?t=si&item=344 ) will do with an adapter with internal 1/8NPT thread and external thread 5/8 X 18 UNF. The speedycables part number is TE7.
Is all that correct?
sounds like a "standard" CAI sender (same as TVR N0125 or http://www.powerstores.co.uk/?t=si&item=344 ) will do with an adapter with internal 1/8NPT thread and external thread 5/8 X 18 UNF. The speedycables part number is TE7.
Is all that correct?
Ok, here is the latest...
The temperature sensor hole on top of the Rover V8 engine is Tiny and the TVR sensor is huge so won't fit with an adaptor! I bought an adaptor 5/8"UNF(M) to 1/8"NPT(F) and this would work to put the Rover sensor in the TVR sensor location - opposite to what we are trying to achieve.
The only option I can see is to find a sensor that fits in the Rover sender hole but has the electrical properties of the TVR sensor - if it exists!
Cheers.. Paul.
The temperature sensor hole on top of the Rover V8 engine is Tiny and the TVR sensor is huge so won't fit with an adaptor! I bought an adaptor 5/8"UNF(M) to 1/8"NPT(F) and this would work to put the Rover sensor in the TVR sensor location - opposite to what we are trying to achieve.
The only option I can see is to find a sensor that fits in the Rover sender hole but has the electrical properties of the TVR sensor - if it exists!
Cheers.. Paul.
philmccann said:
Hi there
Just changed mine over to the RR sender. My problem was that the gauge is out of calibration. How do I know this?, 'cos I "borrowed" a precision resistance box from work (along with a barrowload of various resistors) and tested it. Using the original sender, to correct for the gauge calibration, I would need to have applied LESS resistance in the loop to get the circuit to read right. Obviously this is not possible. So bought a brand new RR sender, carried out resistance v temp reading tests on it, in a pot in the kitchen with a multimeter. Doesn't need to be mega accurate. When I got a sender from Caerbont gauges, during my initial investigations, even they say a tolerance of +- 10% is inherent. Needed to apply a resistor of 150 Ohms to the loop to get the RR sender v gauge calibration correct, and it has never read better since I've had it.
The RR sender is in a far better position to read temperature anyway. The original is in an adaptor creating a sort of "dead" leg where there is little or no water flow.In past investigations I broke the brass adaptor which the original sender screw into. Got a guy to make me one in stainless at work, but when all fitted with the sender there is very little room in the adaptor for any water to get around.So this in itself is far from ideal.
The original set up would never get above ~50DegC when the engine was most obviously above that, and would take an age to even get to there. I have the David Beers Twin temp fan thingy fitted so was confident that all was ok in that department. But always pee'd me off that it didn't read correctly. All sorted now though. Gauge reacts much quicker and is always reading a sensible temperature.
HTH
Phil
It looks like philmccann has already solved this to me?Just changed mine over to the RR sender. My problem was that the gauge is out of calibration. How do I know this?, 'cos I "borrowed" a precision resistance box from work (along with a barrowload of various resistors) and tested it. Using the original sender, to correct for the gauge calibration, I would need to have applied LESS resistance in the loop to get the circuit to read right. Obviously this is not possible. So bought a brand new RR sender, carried out resistance v temp reading tests on it, in a pot in the kitchen with a multimeter. Doesn't need to be mega accurate. When I got a sender from Caerbont gauges, during my initial investigations, even they say a tolerance of +- 10% is inherent. Needed to apply a resistor of 150 Ohms to the loop to get the RR sender v gauge calibration correct, and it has never read better since I've had it.
The RR sender is in a far better position to read temperature anyway. The original is in an adaptor creating a sort of "dead" leg where there is little or no water flow.In past investigations I broke the brass adaptor which the original sender screw into. Got a guy to make me one in stainless at work, but when all fitted with the sender there is very little room in the adaptor for any water to get around.So this in itself is far from ideal.
The original set up would never get above ~50DegC when the engine was most obviously above that, and would take an age to even get to there. I have the David Beers Twin temp fan thingy fitted so was confident that all was ok in that department. But always pee'd me off that it didn't read correctly. All sorted now though. Gauge reacts much quicker and is always reading a sensible temperature.
HTH
Phil
If I have understood correctly these are the steps to getting an accurate temperature reading.
1) Remove the old Range Rover temp gauge sender (small one that looks like a mini spark plug) that has been sitting redundant in the block for many years and is almost certainly knackered
2) Replace it with a new Range Rover temp gauge sender
3) Fit a 150 Ohm resistor between the existing temp gauge wiring & the new Range Rover temp sender
Hey presto all sorted.
Perhaps philmccann can confirm I have understood his solution correctly?
philmccann can you also answer these two questions please.
1) What is the part number for the replacement Range Rover temp gauge sender you used?
2) Can you confirm the Wattage of the 150 Ohm resistor you used?
Thanks in advance for your help philmccann.
Rabbetts said:
The temperature sensor hole on top of the Rover V8 engine is Tiny and the TVR sensor is huge so won't fit with an adaptor!
Did you take the original sender out of the Brass adapter? I don't recall it being very large TBH.All the inlet manifolds have room in the casting to drill & tap whatever you want in similar locations BTW. I frequently remove the throttle heater pipe stub and tap it with NPT thread 'just in case' on manifolds that are off.
hi i bought TE7 adapter+Tt3001-8n sender £21.50 delivered from speedy cables,save youre money they dont fit and of no use what so ever.
what i did was to remove the origional tvr sender,the brass adapter and steel adapter,throw away brass adapter then
drill out steel adapter and re thread to 12mm metric
turn down brass sender and re thread to 12mm metric
sender now sits in water supply as it should guage reads much quicker as its not in dead leg,im sure someone will slaughter me for not using pipe thread but i only have metric tap+dies,hope this saves someone else £21.50,and a lot of head scratching
what i did was to remove the origional tvr sender,the brass adapter and steel adapter,throw away brass adapter then
drill out steel adapter and re thread to 12mm metric
turn down brass sender and re thread to 12mm metric
sender now sits in water supply as it should guage reads much quicker as its not in dead leg,im sure someone will slaughter me for not using pipe thread but i only have metric tap+dies,hope this saves someone else £21.50,and a lot of head scratching
Thanks for that....
I've just noticed another funny - got home after a blast with gauge reading about 91 deg - fans running, switched off engine and turned ignition back on - gauge reads about 81 deg, started engine again and gauge went back up to 91 deg - I presume it's all linked to alternator voltage, ie battery voltage is lower than charging voltage hence gauge reads lower when running from battery alone - engine was only off for seconds so no cooling took place. Still scratching head !!!
I've just noticed another funny - got home after a blast with gauge reading about 91 deg - fans running, switched off engine and turned ignition back on - gauge reads about 81 deg, started engine again and gauge went back up to 91 deg - I presume it's all linked to alternator voltage, ie battery voltage is lower than charging voltage hence gauge reads lower when running from battery alone - engine was only off for seconds so no cooling took place. Still scratching head !!!
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