Mistery temp gauge

Mistery temp gauge

Author
Discussion

coala

Original Poster:

62 posts

291 months

Wednesday 8th May 2002
quotequote all
Starting this spring the temp gauge in my Griff has started to act a bit strange. When driving I never get the temp over 70 degrees. It is still rather cold in the air over here (Sweden) but the thermostat should take care of that. I will take a closer look at this tonight to see if it is stuck open. But...

The weird thing is that the fans still cuts in as they normaly do, in the same situations that I am used to. But the temp gauge is still on 70 degrees when the fans start working. Don't the fans operate on the same temp reading/value as the gauge? At the same time the engine "feels" as it is not as cold as the gauge says.

Anyone experienced this problem? Any tips?

gideonr

64 posts

280 months

Wednesday 8th May 2002
quotequote all
The temp guage in my Chimaera is the same. Never reads above 70, but the fans start when I expect them to.
I suspect the temperature sensor for the guage is faulty, a different sensor is used to turn the fans on (I think).

coala

Original Poster:

62 posts

291 months

Wednesday 8th May 2002
quotequote all
Has yours always been like that? Mine worked fine for years so I am a bit confused at the moment

Anyone sure if the fans and gauge operate on different readings?

shpub

8,507 posts

279 months

Wednesday 8th May 2002
quotequote all
Fans work on a otter switch and are nothing to do with the temp gauge. Sounds like you have a duff temp sensor.

Steve
www.tvrbooks.co.uk

coala

Original Poster:

62 posts

291 months

Wednesday 8th May 2002
quotequote all
My guess too. Thanks Steve! Will still have a look at the thermostat just to be on the safe side...

simont

2,136 posts

280 months

Wednesday 8th May 2002
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Hi,

I had a problem wth my temp gauge since I got the car, readings all over the place, tried all the things called out in Steve's book. This made an improvement but not perfect. Two weeks ago I decided to check the earth connection under the centre console, it was loose (only slightly) so I tightened it up......Every thing is now perfect. Nice steady gauges even when the lights, fans, windows, radio etc are turned on or off
might be worth a try.......

Simon

coala

Original Poster:

62 posts

291 months

Wednesday 8th May 2002
quotequote all
The never ending story of earth connections... One of the few sad things with owning a plastic toy

I do not think that my problem is caused by it though. It should be more eratic then I think. But I will absolutely check it. Thanks!

gideonr

64 posts

280 months

Wednesday 8th May 2002
quotequote all
quote:

Has yours always been like that? Mine worked fine for years so I am a bit confused at the moment

Anyone sure if the fans and gauge operate on different readings?



Yes, the guage has always been incorrect, although I have only had the car 6 months.
One of those jobs, I've never got round to sorting out!

IPAddis

2,479 posts

291 months

Wednesday 8th May 2002
quotequote all
Mine has started to do the same thing. Suspected temperature gauge sender. The sender appears to be in the most inaccessible place on the entire engine. It is very annoying but at least I can use the fan warning lights as an indication of true temperature.

david beer

3,982 posts

274 months

Wednesday 8th May 2002
quotequote all
I dont know if it will of interest but, my sender went bonkers and i now use the unused sender that sits on the top of the block. I think though its only on a Serp engine.

ATG

21,362 posts

279 months

Wednesday 8th May 2002
quotequote all
David, I saw that one too. What's the story with it? Is it intended for an ECU or something?

becky

85 posts

274 months

Wednesday 8th May 2002
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I had this sort of problem with my Griff last year. The gauge would get to read very hot although nothing was happening to indicate that the car was overheating.....it was also completely random and happened at different times and situations. Had the whole cooling system checked and overhauled by two main dealers all to no avail. Hd the gauge and he sendr replaced too. Turned out to be a short on the lead from the gauge to the sender where it came out of the bulkhead and was shorting on the engine. Fortunately repaired by main dealer under warranty and, touch wood, no problems since.

david beer

3,982 posts

274 months

Thursday 9th May 2002
quotequote all
I can only assume its for Rangie's, it is on my Rangie. It is a different connector but allows you to set up the temp guage with a variable resistor. Check the otter turn on point, printed on it. When the fans cut in adjust the guage to show the same. Or you could take pot luck and fit a 90ish ohm resistor which was what my variable was finally set to.Anyway, as we all know there is a bit of a swing in the guage, so its really to show strange behavour!
It might be cheating not to replace things as they break, but i think in this case i can live with it.
David

IPAddis

2,479 posts

291 months

Friday 10th May 2002
quotequote all
quote:

I can only assume its for Rangie's, it is on my Rangie. It is a different connector but allows you to set up the temp guage with a variable resistor. Check the otter turn on point, printed on it. When the fans cut in adjust the guage to show the same. Or you could take pot luck and fit a 90ish ohm resistor which was what my variable was finally set to.Anyway, as we all know there is a bit of a swing in the guage, so its really to show strange behavour!
It might be cheating not to replace things as they break, but i think in this case i can live with it.
David



Is it really as simple as this? Surely that would calibrate it for 90degC but the reading at 70degC could be miles out.

e.g standard sender is 100ohm at 70degC and 300 ohm at 90degC
alternate sender (resistor modified values in brackets) is 100ohm(50) at 70degC and 500ohm(300) at 90degC

Hence the gauge is accurate at 90degC but much too low at 70degC?

Confused!

david beer

3,982 posts

274 months

Friday 10th May 2002
quotequote all
I understand your points.The sender is the other way round ie high resistance when cold, low resistance when hot.If anyones car is running at 70 degrees actual,you are just warming up,or the water thermostat is not working as should be. Or it could be that it has a lower stat fitted.
The important swing of the the temp guage has to be between the water thermostat opening,ie 82 and the fans coming on,ie 96, even on a freezing cold day if the water stat is ok, you will reach its opening point. This swing on the guage would be as accurate as the original set up. I have just measured the cold "12 degrees air temp" and its 780 ohm, so with my 100 ohm resistor its 880.

>> Edited by david beer on Friday 10th May 18:47

>> Edited by david beer on Saturday 11th May 10:14

david beer

3,982 posts

274 months

Tuesday 14th May 2002
quotequote all
confused!
would you like to try my mod? If you dont like it, return it,i will not be upset.
Mod-wise.com

IPAddis

2,479 posts

291 months

Wednesday 15th May 2002
quotequote all
quote:

confused!
would you like to try my mod? If you dont like it, return it,i will not be upset.
Mod-wise.com



I might take you up on that. At the moment, I am more concerned about the new camshaft that is required but I will let you know.

david beer

3,982 posts

274 months

Thursday 16th May 2002
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Oh dear, noisy was it? Mine is, 17k miles, sounding like 117k.

David

IPAddis

2,479 posts

291 months

Friday 17th May 2002
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It's difficult to say how bad it is. A certain dealer on the South coast told me there was nothing wrong with it. Well there is, call me a sad TVR junkie but I know what my V8 should sound like and tapping doesn't come in to it.

That's all it is, a faint tapping noise heard most at 2500rpm under gentle load. Gaskets replaced recently.

It's so embarrassing because it echos off the walls and dulls the sound of the exhaust

david beer

3,982 posts

274 months

Friday 17th May 2002
quotequote all
Yep, mine is the same. Just enough to make a difference. Although my dealer said its normal! My Rangie sounds perfect and my last Griff also.