auxiliary temperature gauge

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Hi guys,
I really liked Tobbys idea regarding the auxiliary temperature gauge.
I googled a bit and I found an australian supplier of "ENGINE WATCHDOG
TM2" which looks quite ok:
http://www.sig.itel.net/#HOW TO FIT THE EASY FITHEAT SENSOR
Has anybody any experience with auxiliary temperature gauges ? Are there
any other other solutions available ?
Thanks & best regards,
Tomaz
 
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Guest

Guest
Tomaz,
I am not sure what the Engine Watchdog temp gauge is supposed to
indicate if the reference temperature is unknown.
If I measure water temp, I know the max temp needs to be below 100
deg. But what's the known max temp of the block at the point where the
sensor is bolted down? Or am I missing something?
--
Rgds,
Roman (London, UK)
'92 HDJ80
On 6/4/07, Tomaz Sustar <[Email address removed]> wrote:
 
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Guest

Guest
Looks clever, I once hired a very old transit van (diesel) 160000+ miles for
the weekend. Drove to Cambridge from Stoke and got a far back as Birmingham
when the temp gauge shot up to just near the red as I came up the M6,
thought about pulling over but by the time I got to a junction the gauge was
going down again and traffic was moving better. Just before the Stafford
junction (20 miles), lost all power, temp gauge OK, pulled over, switched
off engine, opened bonett and it was hot in there, no water in the radiator!
Called AA and while I waited tried to turn it over to see if the engine had
seized, it has. AA man arrived and engine was alot cooler so we put some
water in, stated up! Checked for blown head gasket and drove on to Berwick
upon Tweed (200+ miles) and back, adding 1 litre of water ever 100 miles.
Smoked more before in the morning but otherwise same as before!
Problem is once the coolant is gone the end of the temp sender is not in the
coolant and actually cools down, perhaps because it was mounted in the ally
stat housing not directly into the block!
Tomaz, If you go for these I might ask if you can add a spare temp sender
for use with something else, I have sent them an email to see what the
output is and it is suitable for my purpose.
Malcolm Bagley
Stafford UK
FJ45 '75 & FJ45 '76
I googled a bit and I found an australian supplier of "ENGINE WATCHDOG
TM2" which looks quite ok:
http://www.sig.itel.net/#HOW TO FIT THE EASY FITHEAT SENSOR
Has anybody any experience with auxiliary temperature gauges ? Are there
any other other solutions available ?
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12:47
 
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Guest
I suppose you would have to say it's another reference and know what the
"normal" is. I would guess the outside of the block to a few degrees lower
than the coolant.
As an alternative what about oil temperature, it's a little messy to add a
sender but engine oil is usually a fairly constant number of degrees higher
than the coolant (commonly 6 to 8 degrees) once the engine is fully hot.
Again a larger deviation than you normally see and you could have warning of
a faulty gauge / sender or coolant loss.
Does water temp always stay below 100 deg C - given it's a pressurised
system the red line could be higher or is it marked it deg C. (From memory
I think generators with Perkins diesel engines alarm at 102 and shutdown at
104, had one at 100% load and 94 deg for 4 hours and 110% an 96 deg C for an
hour last week.)
Malcolm Bagley
Stafford UK
FJ45 '75 & FJ45 '76
I am not sure what the Engine Watchdog temp gauge is supposed to
indicate if the reference temperature is unknown.
If I measure water temp, I know the max temp needs to be below 100
deg. But what's the known max temp of the block at the point where the
sensor is bolted down? Or am I missing something?
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.472 / Virus Database: 269.8.7/830 - Release Date: 03/06/2007
12:47
 
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Guest

Guest
Hi Malcom,
I'm still looking for other options ... - but this "watch dog" is
exactly what I'm looking for - it is quite simple and no modifications
are required.
If I will order it I will definitely order spare senders ... I'll decide
about ordering it in a couple of days.
regards,
Tomaz
 
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Guest

Guest
Hi Roman,
I'm not sure what do you mean by reference temperature ... it is an
absolute measurement of the temperature at the point where the sensor is
located - it can be on engine block, on the pipe etc...
The idea is to have a sensor without any "corrections" as the stock
gauges have.
My idea is to mount it and then according to the ranges obtained, when
the engine is working fine, set the alarms. Of course it will take some
time to figure out the optimal location and temperature ranges.
Regards,
Tomaz
 
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Guest

Guest
Malcolm,
If Toyota quoted the figure for the "normal" maximum engine block
temp, this would be ideal. Otherwise, it's guesswork - a few degrees
lower than x, with the alarm set at still a few degrees lower. Such
accuracy is already provided by the instrument panel gauge, isn't it.
Why not use a bog standard temp sender showing the actual coolant temperature?
--
Rgds,
Roman (London, UK)
'92 HDJ80
On 6/4/07, Malcolm Bagley <[Email address removed]> wrote:
 
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Guest

Guest
Only because if the gauge is faulty or fails you end up guessing, two
senders and gauges would prevent that and I think all Toyota's have the
sender directly in the block but vehicles like the transit I hired with a
sender in the stat can fail to indicate overheating once the coolant has
gone, might even be true of senders in the block, if the "dry" heat affects
the sender in a different way the wet coolant.
You are right the engine block does not have a quoted "normal" temperature,
it might not be possible to determine one for it - I would suggest high
ambient temperatures will give higher readings closer to the coolant, sub
zero outside temps will mean the temperature of the outside of the block is
further reduced from the coolant.
Indication and what you are used to seeing are key, not accuracy, but two
sources of information that normally correlate help you see when trends are
not being followed.
Malcolm Bagley
Stafford UK
FJ45 '75 & FJ45 '76
Why not use a bog standard temp sender showing the actual coolant
temperature?
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Checked by AVG Free Edition.
Version: 7.5.472 / Virus Database: 269.8.7/830 - Release Date: 03/06/2007
12:47
 
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Tomas,
I don't think you will be able to avoid "corrections" if you try to
tie the coolant temperature to a temperature measured elsewhere in the
engine. Too many variables.
The reference temp I referred to is the maximum temperature of the
block at the point of measurement which directly corresponds to the
maximum temperature of the medium you wish to measure, coolant in this
case. Because there is no data in the factory manual describing
temperatures at various points of the engine block, using this method
for measuring coolant temperatures is rather unpredictable.
Even if you measure the engine block at the "normal" coolant temp, it
will be a wild guess to say that the relationship between the two
temperatures is linear, i.e if the engine block temp varies by 10
deg., the coolant temp also varies precisely by the same amount.
IMHO It's better to use an adapter inserted in the radiator hose and
stick a sensor in it. Additionally, if you use a dual adaptor, you can
also stick another sensor next to it to tell you when the coolant
level starts dropping down. This will be even more useful because it
will tell you about a coolant leak. This is no less disastrous to the
engine because with less coolant the engine temperature leaps much
faster.
--
Rgds,
Roman (London, UK)
'92 HDJ80
On 6/4/07, Tomaz Sustar <[Email address removed]> wrote:
 
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Guest
Hi Roman,
I think what Toby wrote in replay to my radiator size question is a key
issue : "The gauge on many 80 series has a logic circuit built in which
keeps it at the halfway mark until a major variation in engine
temperature takes place. This means that when the gauge does move it
looks pretty dramatic."
I read about that with respect to volkswagen and from my experience I
would say that toyota uses the same principle to "calm us down".
Ragards,
Tomaz
 
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Tomaz,
For such a simple gizmo as the temp gauge, "built-in logic circuit "
sounds like a glorified hysteresis.
I's not a devious plan by Toyota engineers to keep us under sedation.
Rather, because the gauge is so simple and hence so inaccurate, the
more hysteresis, the less the users will complain.
--
Rgds,
Roman (London, UK)
'92 HDJ80
On 6/4/07, Tomaz Sustar <[Email address removed]> wrote:
 
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Guest

Guest
Hi Roman,
I completely agree with the thing you mentioned ... my initial idea was
also to measure the coolant temperature but since the cooling system is
quite sensitive (leaking ...). So I started to search for other
solutions ... thats how i come to "watch dog".
Have you any idea are there any "safe" solutions available for direct
coolant measurements ?
regarding the hysteresis - makes sense ...
the fact is that when I go on trip I just hate to constantly monitor the
temperature gauge - so I thought that alarm would be a perfect solution...
regards,
Tomaz
 
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Guest

Guest
Tomaz,
I don't know how technically minded you are (machining, electronics).
Devising a system to measure the parameters you want is within the
reach of an reasonably advanced amateur, such as myself.
Although I've never bothered with a temp gauge - my engine runs pretty
cool and never gives me a problem - I have a temp alarm which I have
developed myself using the signal supplied by the toyota sensor the
stock dashboard gauge.
It's basically an op-amp Schmidt trigger changing state when the
voltage level increases beyond a preset value. The "watch dog"
probably works like this, only has a few bells and whistles added,
like a digital display to play with in traffic jams.
I have an adapter fitted in the top radiator hose and it is as safe as
it could be - no leaks, no probs, just two good quality hose clips.
You can get such adapters made of coloured aluminium from motorsport
shops, or if you have access to a machining workshop, have it made of
stainless steel for a fraction of the cost.
Let me know if you are interested to follow this route.
--
Rgds,
Roman (London, UK)
'92 HDJ80
On 6/4/07, Tomaz Sustar <[Email address removed]> wrote:
 
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Guest

Guest
Roman,
"sounds like a glorified hysteresis"
'Anti-hysteria hysteresis' may well be exactly what it is, though I suppose
a gauge would need a cleverer sort of hysteresis than a light or alarm.
Like you I've never found cause to get too worried by engine temps. Keeping
the cooling system in reasonable order has always done the trick for me.
All the best,
Toby
1990 HDJ80 UK
 
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Guest

Guest
Hi Roman,
my technical skills are somehow limited - I'm not very handy but I know
a lot of guys who are fare better then me and I usually ask them to sort
out the details.
I'm very interested in sorting out this temperature alarm so I'm
interested in following your route.
I have one question regarding your solution - If I understood correctly
you use the existing Toyota temperature sender and some custom made
electronic which is processing this signal - It is not clear to me why
you need an aluminum adapter then ?
What else beside Schmid trigger would I need ?
tnx & Regards,
Tomaz
 
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Guest

Guest
Tomaz,
You are correct, the water temp alarm does not require an external
sender. It is driven by signal sent from the OEM sender to the gauge.
The adapter, like this one:
http://www.demontweeks.co.uk/resources/images/zoom/GLOHA.jpg
is for fitting an separate temp sender, or in my case a coolant level sensor.
If you just want to monitor water temperature, there's still one more
option - SPA Design
electronic or stepper motor analogue gauges. They are programmable
and have a built in alarm function.
Have a look here: http://www.spa-uk.co.uk/design/watergauges.asp
--
Rgds,
Roman (London, UK)
'92 HDJ80 (auto)
On 6/6/07, Tomaz Sustar <[Email address removed]> wrote:
 
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