Stepper & temp gauge question
Discussion
Evening all,
Chimaera ownership for 3 weeks now and still grinning!!
Getting shocking fuel economy at the moment....no where near 33mpg apparently achieved on other threads(tee hee hee)! The temperature gauge seems to sit at around 60C for the first 20 mins (at least) under normal driving load and the idle revs appear to hover around 1200 during that 'warm-up' time. I'm thinking that the ECU thinks that the engine is cold and continues to squirt in fuel accordingly.
So, what do you reckon? Stepper motor clean out should get the idle revs sorted? Temp gauge problem is either thermostat to radiator glitch or otter switch?
A nice cold virtual beer goes to the most sensible response
Cheers
Phil
Chimaera ownership for 3 weeks now and still grinning!!
Getting shocking fuel economy at the moment....no where near 33mpg apparently achieved on other threads(tee hee hee)! The temperature gauge seems to sit at around 60C for the first 20 mins (at least) under normal driving load and the idle revs appear to hover around 1200 during that 'warm-up' time. I'm thinking that the ECU thinks that the engine is cold and continues to squirt in fuel accordingly.
So, what do you reckon? Stepper motor clean out should get the idle revs sorted? Temp gauge problem is either thermostat to radiator glitch or otter switch?
A nice cold virtual beer goes to the most sensible response
Cheers
Phil
The over cooling issue is more common than you think, especially if a replacement rad has been fitted at some point.
The Chims & Griffs historically have had a reputation for overheating, but my experience is just the opposite.
Its true the temperature sender in not in the best spot, many will tell you that's why the gauge under reads.
I'm not so sure the temp sender position is the problem.
At first I thought I had the wrong thermostat fitted or it was stuck open, but it all checked out fine when I investigated.
I fitted a new thermostat anyway, it made absolutely no difference.
The Chim has a good heater but it doesn't do a thing until the coolant temperature gets to 70 on the gauge.
I was freezing last winter, even with the roof on, so irrespective of what the gauge is telling me there is no doubt my car genuinely over cools.
So I fabricated and fitted an old skool adjustable rad blind.
I don't use it in the summer but now the outside temperature is starting to drop I will be putting it back in.
In the depths of winter the rad blind is adjusted to completely cover the rad, its a simple case of restricting the airflow sufficiently to maintain a decent operating temperature without causing the car to overheat in traffic.
The optimum running temperature is somewhere between 80 - 90 degrees.
If your car runs at 60 (and the heater is cold) there is a good chance your getting close to the car going into cold start fueling.
Blitzracing will probably have the exact temperature cold start fueling happens, when it does there is a massive amount of fuel chucked in.
If I were you I would fit a rad blind before it gets much colder!
Can I have my beer now?
The Chims & Griffs historically have had a reputation for overheating, but my experience is just the opposite.
Its true the temperature sender in not in the best spot, many will tell you that's why the gauge under reads.
I'm not so sure the temp sender position is the problem.
At first I thought I had the wrong thermostat fitted or it was stuck open, but it all checked out fine when I investigated.
I fitted a new thermostat anyway, it made absolutely no difference.
The Chim has a good heater but it doesn't do a thing until the coolant temperature gets to 70 on the gauge.
I was freezing last winter, even with the roof on, so irrespective of what the gauge is telling me there is no doubt my car genuinely over cools.
So I fabricated and fitted an old skool adjustable rad blind.
I don't use it in the summer but now the outside temperature is starting to drop I will be putting it back in.
In the depths of winter the rad blind is adjusted to completely cover the rad, its a simple case of restricting the airflow sufficiently to maintain a decent operating temperature without causing the car to overheat in traffic.
The optimum running temperature is somewhere between 80 - 90 degrees.
If your car runs at 60 (and the heater is cold) there is a good chance your getting close to the car going into cold start fueling.
Blitzracing will probably have the exact temperature cold start fueling happens, when it does there is a massive amount of fuel chucked in.
If I were you I would fit a rad blind before it gets much colder!
Can I have my beer now?
had same sort of concerns about temps ie gauge readings seemed low,there are lots of posts here on this subject it seems with good advice. mine would struggle to make 70 on gauge when driving so i thought it may be stat stuck etc. . however got ir heat temp sensor and checked temps around engine/cooling system and found that the stat/otter switch were opperating spot on (fans on 90+ off 88+/-) it would appear that the system is fueling correctly as passed emissions (mot last wknd) with good readings, it would appear that in my case the gauge "under" reads 10deg which isnt uncommon according to findings listed here ! the thing to establish is what the real temps around cooling system are , if the car is warmed up to the point where the fans come on while stationary (otter working correctly)take a look at the temp gauge and see if the temp corresponds to the switching temps +/- 90deg, found this is a good starting point to know what to investigate 1st/next, good luck ! 
Although I totally agree that the gauge is not the most accurate instrument in the world, I feel I should point out my heater output follows the gauge readings very closely so it does work.
My thermostat & otter switch also work exactly as they should, checking the temperatures with a IR gun only tells you whats going on when the car is not moving.
On my Chim the problem is not when the car is stationary, its when the car is moving at speed.
Forget the gauge for a minute, its the heater output proves exactly whats happening.
Without the rad blind my Chim is freezing in the winter when on the move, everything comes good when I slow to 30 mph.
After a period of town driving the engine coolant temps are spot on & the heater works great.
Then as you increase speed above 30 - 40 mph the temperature slowly starts to drop again until after 10 minutes at 60 mph there is no heater output and the gauge refuses to rise above 60 degrees.
With my rad blind its a totally different story, here are my winter results with & without rad blind.
Heater output: 100%
Heater output: 100%
The gauge never goes over 90 but the fans do stay on a bit longer than when no blind is fitted
Heater output: 0% Brrrrrrrrr
Heater output: 70 - 80%
Basically with my rad blind correctly adjusted I can achieve very similar running temperatures as I get in the summer months with no rad blind.
With no rad blind I absolutely freeze in the winter, with the rad blind fitted the interior maintains a very comfortable temperature.
Its all about air flow, with respect measuring the temperatures at idle doesn't tell you a thing.
Its very important to point out that my results are for my particular car, all our cars are a bit different, there are so many variables.
Its also very important that you take it in stages when covering your rad.
OVER DO IT AND YOU RUN THE RISK OF SERIOUS ENGINE DAMAGE!
My thermostat & otter switch also work exactly as they should, checking the temperatures with a IR gun only tells you whats going on when the car is not moving.
On my Chim the problem is not when the car is stationary, its when the car is moving at speed.
Forget the gauge for a minute, its the heater output proves exactly whats happening.
Without the rad blind my Chim is freezing in the winter when on the move, everything comes good when I slow to 30 mph.
After a period of town driving the engine coolant temps are spot on & the heater works great.
Then as you increase speed above 30 - 40 mph the temperature slowly starts to drop again until after 10 minutes at 60 mph there is no heater output and the gauge refuses to rise above 60 degrees.
With my rad blind its a totally different story, here are my winter results with & without rad blind.
- Town (30 mph & below) no rad blind
Heater output: 100%
- Town with rad blind
Heater output: 100%
The gauge never goes over 90 but the fans do stay on a bit longer than when no blind is fitted
- A road & motorway driving (50 - 60 mph & above) no rad blind
Heater output: 0% Brrrrrrrrr
- A road & motorway driving with rad blind
Heater output: 70 - 80%
Basically with my rad blind correctly adjusted I can achieve very similar running temperatures as I get in the summer months with no rad blind.
With no rad blind I absolutely freeze in the winter, with the rad blind fitted the interior maintains a very comfortable temperature.
Its all about air flow, with respect measuring the temperatures at idle doesn't tell you a thing.
Its very important to point out that my results are for my particular car, all our cars are a bit different, there are so many variables.
Its also very important that you take it in stages when covering your rad.
OVER DO IT AND YOU RUN THE RISK OF SERIOUS ENGINE DAMAGE!
Edited by Chimpaholic on Thursday 9th September 08:28
I should also say that a more complete solution to my rad blind would be to fit winter and summer thermostats.This was common practice in the 1950's, when you went in for your summer mono grade oil to be changed for winter grade a winter thermostat was often fitted too.
Then in the spring you went back to summer mono grade oil & the summer thermostat went back in.
The thing is its just so much quicker and easier to raise and lower my rad blind than keep alternating thermostats when the seasons change.
A second adjustable thermostat plumbed into the cooling system with summer & winter settings, now there's an idea
Naybr said:
Sorry - I don't 'get' this. If you have the standard 82 degree thermostat fitted then surely there should be no water circulating through the rad below this temperature and therefor the rad blind shouldn't make any/much difference ...?
Well certainly it does make a difference I can assure you!The truth is my thermostat is opening and closing all the time as it desperately tries to hold the engine temperature at 85 - 90 degrees.
A thermostat is not exactly the most sophisticated piece of technology, and its certainly not the only component in the cooling system that governs engine temperature.
Its also worth remembering that a thermostat can only respond to the coolant temperature in the immediate vicinity of its location point within the cooling circuit.
The thermostat is mounted high in the coolant system, like air hot water rises, the temperature of the coolant below the level of the thermostat in the engine circuit may well be 15 degrees lower than what the thermostat is responding to.
As the engine circuit coolant in the vicinity of the thermostat reaches 82 the thermostat opens and allows what is sitting in the rad to circulate around the engine.
The thing is what's been sitting in the rad is by now so damn cold it almost immediately reduces the temperature of the complete cooling circuit to well below 60.
So the thermostat duly shuts again, the engine coolant temperature again surges up to 82 in the area where the thermostat is mounted, it opens & and incomes another massive dose of freezing cold water.
The cycle is never well enough controlled to maintain the correct constant running temperature, in the winter the overriding controlling element is all that cold coolant sitting in the rad that's been massively chilled by winter air flow.
That's why there is a thriving trade in rad blinds for Land Rovers fitted with the RV8.
The temperature is not only controlled by the thermostat, the rad capacity plays a big part too.
If you don't believe all this and your Chim runs cold in the winter with a poor heater; assuming the thermostat is working correctly I would strongly advise fitting a rad blind.
Keeping what's sitting in the rad warmer is the secret here.
A rad blind certainly worked for me and thousands of Land Rover owners too, FACT.
Remember chaps, stay warm this winter and if you know a pensioner with a Chimaera we recommend you check on him daily
Edited by Chimpaholic on Thursday 9th September 12:42
re/chimpaholic . . i agree with your pointers as you said,and as i said its realy just a starting point to establish if the gauge is anything like what the temps are actualy reaching/not reaching , didnt maean to confuse or contradict just throwing another idea into the post that had proved useful for me,
Chimpaholic said:
Naybr said:
Sorry - I don't 'get' this. If you have the standard 82 degree thermostat fitted then surely there should be no water circulating through the rad below this temperature and therefor the rad blind shouldn't make any/much difference ...?
Well certainly it does make a difference I can assure you!The truth is my thermostat is opening and closing all the time as it desperately tries to hold the engine temperature at 85 - 90 degrees.
A thermostat is not exactly the most sophisticated piece of technology, and its certainly not the only component in the cooling system that governs engine temperature.
Its also worth remembering that a thermostat can only respond to the coolant temperature in the immediate vicinity of its location point within the cooling circuit.
The thermostat is mounted high in the coolant system, like air hot water rises, the temperature of the coolant below the level of the thermostat in the engine circuit may well be 15 degrees lower than what the thermostat is responding to.
As the engine circuit coolant in the vicinity of the thermostat reaches 82 the thermostat opens and allows what is sitting in the rad to circulate around the engine.
The thing is what's been sitting in the rad is by now so damn cold it almost immediately reduces the temperature of the complete cooling circuit to well below 60.
So the thermostat duly shuts again, the engine coolant temperature again surges up to 82 in the area where the thermostat is mounted, it opens & and incomes another massive dose of freezing cold water.
The cycle is never well enough controlled to maintain the correct constant running temperature, in the winter the overriding controlling element is all that cold coolant sitting in the rad that's been massively chilled by winter air flow.
That's why there is a thriving trade in rad blinds for Land Rovers fitted with the RV8.
The temperature is not only controlled by the thermostat, the rad capacity plays a big part too.
If you don't believe all this and your Chim runs cold in the winter with a poor heater; assuming the thermostat is working correctly I would strongly advise fitting a rad blind.
Keeping what's sitting in the rad warmer is the secret here.
A rad blind certainly worked for me and thousands of Land Rover owners too, FACT.
Remember chaps, stay warm this winter and if you know a pensioner with a Chimaera we recommend you check on him daily
Edited by Chimpaholic on Thursday 9th September 12:42
Pink_Floyd said:
Chimpaholic said:
And a caravan window blind.
Where did you get the window blind from.It has and internal spring so it self retracts, the blind material is windproof, waterproof and very durable.
Mounted upside down you pull a cord upwards to cover how much of the rad you want to block off.
I used a sprung loaded barrel type locking toggle on the cord to hold the blind in the chosen position so its infinitely adjustable between fully open & fully closed.
Press the button on the locking toggle and the blind snaps open in a second exposing the rad, I did it this way just in case the coolant temperature went too high and I need air flow through the rad in a hurry.
To facilitate fitting the system without removing the rad I designed it in two parts.
1) The stratocore corrugated plastic surround
2) The caravan blind itself
The stratocore surround and blind fit together with industrial Velcro to make one unit
I just slide the stratocore surround down the little gap between the rad & the slam panel, it locates nicely in the lip at the bottom of the rad.
Then after removing the front numberplate its an easy job to pass the blind through the grill aperture (facelift Chims only) & attach it to the surround.
Surprisingly I found in the winter the car runs to optimum temperature at all speeds with the rad completely covered, the only difference is the fans stay on slightly longer when in town but they always go off even in queuing traffic.
The temperature never goes over 93 on the gauge; I saw readings of 95 queuing outside St Tropez this summer with no blind fitted so I know its safe.
The main benefit is the car stays nice and warm even at a steady 80 mph on a freezing cold day.
I honestly wouldn't be without it in the winter months.
Edited by Chimpafrolic on Thursday 28th October 16:15
I have noticed the cooler running of the car in recent weeks. Mine is as described - in town nice hot feet and on the open road it soon cools down quickly. I have a piece of board in the boot to go back in but would love to have something that had a bit of adjustment on it if anyone knows where to get them - couldnt find anything on Land Rover blinds.
Naybr said:
Sorry - I don't 'get' this. If you have the standard 82 degree thermostat fitted then surely there should be no water circulating through the rad below this temperature and therefor the rad blind shouldn't make any/much difference ...?
I think that the rad blind is also cutting down the through-flow of air which cools the block directly - I know that at speed the airflow through teh engine bay provides more cooling than the radiator itself as my Chim ran for a few months with a blocked rad and I only realised it was blocked when I got caught in traffic. At speed it would run at about 60 degrees with a pretty much knackered rad.Phil
Thanks. I'm happier with this explanation as to why the rad blind works. I I wasn't too sure about the 'pulses of cold water' theory, because I'm sure they would show on the temp gauge. Incidentally, my temp gauge is much more sensitive now I've moved to the 'Rover' sensor. This is definately a good mod. too.
One thing, you need to make sure the temp guage is reading correctly! I bought a little hand held IR temp measuring device and when hot measured the engine temp various places that made sense, like the front of the engine right where the temp sedning unit is, and I consistantly measured the engine at 10 deg hotter that the dashboard gauge was reading. At normal opperating temp on a normal summer day it would read 70 degrees, when very hot on a hot day it would read 85. I know that engine was really 10-15 degrees hotter than that.
Then in a conversation with David Beer, he told me TVR use a different temp sending location than Rover, and the TVR sensor goes into a blank spot internally, i.e. not in water or oil. You can see the Rover sensor on top of the intake manifold behind the distributor. It's possible to put a resistor between the TVR wire and the Rover sender and use that sending unit.
Does anyone have any experience doing this?
Then in a conversation with David Beer, he told me TVR use a different temp sending location than Rover, and the TVR sensor goes into a blank spot internally, i.e. not in water or oil. You can see the Rover sensor on top of the intake manifold behind the distributor. It's possible to put a resistor between the TVR wire and the Rover sender and use that sending unit.
Does anyone have any experience doing this?
Yes its pretty straightforward. You just need to be a bit handy, and you need a 180 ohm resistor. These cost pennies from Maplin - get the biggest one you can find, for robustness rather than any electronic reason.
Its then a case of making up a connector which goes on the 'peg' on the top of the Rover sender. I squashed down a f/f 'bullet' connector. soldering it to the resistor and the other end to a female lucar connector. I then tidied the whole thing up with heat shrink.
Then just unplug the cable from TVR sender and plug in onto your new one.
I found that the whole thing is now much more sensitive. You can 'see' the engine warming up earlier, and it generally moves about a bit more in and out of traffic.
Its then a case of making up a connector which goes on the 'peg' on the top of the Rover sender. I squashed down a f/f 'bullet' connector. soldering it to the resistor and the other end to a female lucar connector. I then tidied the whole thing up with heat shrink.
Then just unplug the cable from TVR sender and plug in onto your new one.
I found that the whole thing is now much more sensitive. You can 'see' the engine warming up earlier, and it generally moves about a bit more in and out of traffic.
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