Adding coolant temp gauge? (1 Viewer)

[cruiserdan]

The back-light will be white which will bug you 'cuz it won't match the other gauges.

Get yerself two 84998-10050 bulb covers and stick'em on. Your lighting color with match the rest of the panel then...

 

[Rich]

TurboCruiser, your disagreement does not constitute offense. Nor do you need to apologize for disagreeing. I just state the facts as I see them. I don't expect anything different from others.

In the scheme of things, it's just a temp gauge!

 

[semlin]

here is the hdj81 dash showing the turbo tach with led. the face is not the same so I don't know if there would be a mount hole in behind or not. I guess we could do somehing similar in behind the temp gauge pretty easily.

 

[Beowulf]

I think for my testing of the gauge I will get a cheap electric hot plate, they are generally weak and may be more controllable than a propane stove, I think I will heat a pot full of ATF (cheap low viscosity oil), the added mass should slow

Raven,

I can confirm that if you heat 10w30 engine oil in your wife's kitchen, she will become angry, spew expletivies, and you will get no peace at night.... for several nights. Keep this experiment in the garage

As for the discussion on guage marking, this is how I've got my Greddy marked. It also has a red warning light that can be set to any temp (Mine is set at 230 IIRC. I plan to hook a piezo like Bill's the next time I'm doing electrical work. The green mark is approximately the normal range after the stock thermostat opens. My gauge moves ever so slightly between the green and sometimes approaches the yellow mark. I can't recall how I chose the yellow mark but it was from some analysis that someone had done in a prior cooling thread. The red mark is approximately 226 where the A/C will cut off if you are running the A/C. That's a major point that people should remember since most people don't run AC all year long and cooling systems can fail at any time.

-B-

 

[RavenTai]

-B- sounds like you have experienced the results of using the kitchen as a garage.

Is that green 93c (200 F) , yellow 106 C (223 F) , red 114 C (237 F)?


So 200 F could be a good typical operating temperature when everything is going right? Temps into the 210’s are not uncommon but never over 226?

Found a reference in the FSM under “normal conditions” for “coolant temp after warming up ” via the ECT sensor as 80-95 C (176-203 F ), on the same page it states the SFI system is in closed loop after warming up, leads me to believe closed loop happens at >176 F (80 C) any confirmation?

 

[RavenTai]

Dan had some good info on this that answers some of the open questions. * Warning * the following prices are current as of 8-05 and will certainly change over time.

First off 93-97 the "temp gauge sender" (AKA thermistor) is the same, part # 83420-16040, smart shopper price is $16.30, List $21.73. Quite reasonable. I'll be ordering two of these soon for testing.

Also to my surprise the oil pressure & water temperature gauge assembly can be purchased separately from the cluster, 95-97 take the same gauge. So then the question becomes what is different about the 93 & 94 gauges? They all take the same sender so is the 93/4 gauge electrically the same just different mounting or arrangement, could it be as simple as differences in face card markings? Will have to look into that. if someone with a 93/94 is adventurous and has a camera would be good to see what that gauges circuit looks like. Could also wait until there is a mod available and see then.

The 95-97 gauge assembly list for $144.67 smart shopper price is $108.50 a little to steep for possibly destructive testing (multiple solder/de-solder finger prints on the face, testing/drilling for lights, case rash etc) but if the search for a used one drags out for too long might be the only option.

Got a sender/thermistor out of a spare head, I think it was a 95, did some room temperature resistance readings, and then a stove top water test (80-212 F ) like every one else results do not line up with anyone else. The circumstances of the test have problems at every step.

Picked up a hot plate tonight at Wally world very cheap,

Going to look for a large chunk of aluminum, failing that I do have a chunk of steel. The chunk will be drilled for the sender/thermistor and for a temperature probe, I am working E-bay right now for a good quality digital thermometer that takes remote probes.

The chunk of metal will be immersed in oil and sitting on an insulator of some sort so the bottom of the chunk does not touch the bottom of the pot, that way the oil can evenly heat the piece on 5 sides, the mass of the chunk should guarantee the sender and temp probe are seeing the same temperature and slow the process down, also a good place to make a good reliable ground.

 

[RavenTai]

here is a pic of the first dry run resistance test, I was worried about the accuracy of the tiny cooking thermometer but it did read just over 210 F in boiling water, but the water was tap and I am not sure exactly what water boils at this altitude, the ground was questionable but resistance to the body of the thermistor stayed below 1 ohm during the test, also the condition of the thermistor is unknown.

I will be setting up a better test bed for higher temperatures and accuracy. (moving it to the garage)

 

[semlin]

raventai, did you happen to ask Dan about the 91-92 gauge? The visible dash on a 91-92 is identical to a 93-94 afaik.

 

[RavenTai]

I did not, I will ask next time I talk to him. No one has ever found out if the 91-92 has the flat spot eh?

 

[semlin]

Good news,

Dave Dearborn at Urban Land Cruisers has kindly agreed to donate the temp gauge from the LX450 he is currently wrecking. I'm sure you'll join me in thanking Dave for a generous gesture. Raventai, it seems like you are the mad professor on this one, so PM Dave with your address particulars, and once he gets the thing pulled we'll get this show on the road!

 

[cruiserdan]

The 91-92 gauge is a different part number as is the 93-94 gauge. The 93-97 gauges use a sender common to both. The 91-92 uses a different sender.

 

[RavenTai]

Good news,

Dave Dearborn at Urban Land Cruisers has kindly agreed to donate the temp gauge from the LX450 he is currently wrecking. I'm sure you'll join me in thanking Dave for a generous gesture. Raventai, it seems like you are the mad professor on this one, so PM Dave with your address particulars, and once he gets the thing pulled we'll get this show on the road!

That is good news and That is very generous of him, I am in the area so I can go pick it up

I'll get on it, thanks very much for the Help Semlin

Got a chunk of aluminum Saturday.

I was just on Ebay, I have a line on a used Omega thermocouple digital thermometer with 2 inputs, will know if I won it tonight. (sniping)

Looks like everything is falling into place

I am about to go to Alaska for a few days (Aug 30 through Sep 3) but will be able to work on it in earnest in early September and should have be done by mid to late September baring any major problems.

 

[cary]

Sweet, I am so glad that someone with a little ee is getting this done.

Cary

 

[batman]

If you aware of a good beginers manual for learning basic circuitry and testing, I'd love to read up and learn more. I had a 100 level EE circuits class about 15 years ago, but most all that has left me. I know about how to turn my voltage meter on, but I still find myself finding out that something is hot... the hard way .


Rookie2

Did you ever get an answer on your question of were or what is a good book to learn basic circuitry and testing? If not PM me and i will look on monday to see if I have an extra book at work, IF so I will send it to you. I forget the name but it's a great book for a noob...

 

[Rookie2]

Did you ever get an answer on your question of were or what is a good book to learn basic circuitry and testing? If not PM me and i will look on monday to see if I have an extra book at work, IF so I will send it to you. I forget the name but it's a great book for a noob...

Thanks Batman.

Raven gave me a great tip on a circuits and electronics book earlier in this thread. I picked it up on Albris, shipped to the door for $7. Not bad. I've gotten through the first two chapters, and it seems like a very helpful book.

Thanks again though for the offer.

Rookie2

 

[RavenTai]

progress report,

Went and Dave Dearborn’s shop today, Urban Land Cruisers witch turns out is fairly close to where I work, I picked up the gauge he donated, really nice guy and a nice shop, lots of cruisers to look at, the donor was a clean 97 LX before it was wrecked, stock, no apparent mods at all, water temp gauge looks to be in perfect condition. Big thanks to Dave for the part.

I got a used Omega HH509R digital thermometer in a few days ago, I compared it at room temperatures against a similar unit and thermocouples with current calibration stickers, they were within a degree probably closer still, but air currents kept the readings moving around (on both meters) preventing a precise comparison, just walking up to them made the reading go up from body heat.

I ordered 2 new "T type" thermocouples directly from Omega, they should be here on the 30th, when those arrive I’ll try some shade tree calibration checks like comparisons to other thermometers and boiling distilled water, still have not been able to find out what the boiling temperature of water is at my altitude but it is only ~840’ above seal level at the house so not much less than 212* F, I would think within 2-3 * F should be accurate enough for this purpose. 212 is a nice calibration point as the temperatures we are primarily interested in are in this area and is easy to accurately achieve.


This is about as far as I will be able to go until I get back from vacation.


more to come.....................

 

[Rich]

Raven, when you get a chance, put a magnifiying glass on the temp gauge diode and see if there are any numbers to read. Thanks.

 

[RavenTai]

Edit oops you said Diode not thermisor,

will do. last time I looked at the one from my truck there was only a black band indicating polarity, the new victem gauge appears the same at a glance but I will have a closer look.









there are. this I sent in a PM:

"I pulled the thermistor out of what I think is suppose to be a 95 head......................


The one I have from the spare head has markings on each of its 6 flats, it is the only water temp sensor that has only one pin on its connector.

Starting with "A" within a circle.
The next looks like an odd lower case "r" in a circle,
"ND" within a circle, NipponDenso’s logo IIRC
"205",
"29",
And the last flat "10N" ...........................

I briefly tried to make sense of the markins, maybe relating to temprature ange or resistance but did not get far, I have heard of thermistors sometimes called 10K for 10,000 ohms, dont know if that relates to the 10N

 

[RavenTai]

Ok there after closer examination there does appear to be more there than just a stripe, besides the wide stripe at the end on top is what looks like a "3" with a line going through part of it, maybe the line is just extra/smeared dye or an inclusion in the clear case, there appears to be something on the bottom also but cannot get a good angle on it,

I apologize for the lack of good angles I cannot get a strait down or straight up shot as it is sandwiched in the gauge and this thing is the size of a rice grain. First shot is of the whole thing for reference , the first 2 after that are from something similar to that angle but different elevation.

 

[batman]

Thanks Batman.

Raven gave me a great tip on a circuits and electronics book earlier in this thread. I picked it up on Albris, shipped to the door for $7. Not bad. I've gotten through the first two chapters, and it seems like a very helpful book.

Thanks again though for the offer.

Rookie2

No problem, anytime I am just glad to be a part of the Land Cruisers. This is a good group of people....