mr2y
Mine was 741 ohms which was about 50 degrees according to your chart. About right since it was cooled off from driving a coupe of hours ago. I tried getting voltages but failed, I'll have to play with that some other time.
 

Hoonsy
Also how would I test it? Just the positive probe into the back of the positive pin/negastive into the back of the negative pin?

 
I couldn't fit my hands in there so I unplugged the C connector of the ECU (the middle one) and stuck the multimeter across red and brown according to my pinout here: http://imgur.com/6hGuEOc
 
Edit: forgot to mention my ECU was getting a battery in voltage of 10v :/ might have to check that out some time, I might have some dodgy wiring as mentioned in another post I read where the early gen wiring harnesses had corrosion to the ECU.

Thanks for going out of your way to help me figure this out, really appreciate it :)
That's a shame about the power supply, obviously something is playing up. Good luck with sourcing the cause!

I might pick up a multimeter tomorrow (SCA have a sale going on I think) and I'll give that sensor a test. I'm considering not bothering anyway, as I'm going to order a coolant thermostat+gasket from my local Toyota dealership, and I figured I may as well get a new coolant temperature reader+gasket while I'm at it. Hopefully they price it reasonably.. they don't have a good history

Yep I would go the thermostat install first, at least you know your engine is physically running at the right temp, then you can test other sensors and what not.

Alright mad, thanks for all your help Paul :)
Still waiting on my quote. I'm thinking if I can find the part numbers, I'll use Amayama to try and source them
Also that toyotamarket.ru/jp link wasn't working for me. I tried just toyotamarket.ru but there's no where to go from that page haha

Hi Hoonsy,
I have been following your fuel consumption thread with interest, I have always thought that I use too much but have never properly checked.
About your Thermostat issue, I know that Redtarga on this forum has written a detailed procedure for changing Thermostat without fully draining the coolant.
I reckon that it may be a "sticky" in the how to section of this forum.

Peter
Hi Hoonsy,
I have been following your fuel consumption thread with interest, I have always thought that I use too much but have never properly checked.
About your Thermostat issue, I know that Redtarga on this forum has written a detailed procedure for changing Thermostat without fully draining the coolant.
I reckon that it may be a "sticky" in the how to section of this forum.

Oh didn't know there was a write-up on this forum. I'll have to check it out, thanks Peter
Glad to hear you found it interesting - shame there hasn't been much of an improvement/conclusion made yet haha, however I feel mr2y is on to something regarding my thermostat. 
As for your fuel consumption, can you roughly guess how much you use per 100km?

- snip - 

Edit: I need to start thinking before I post from now on.. turns out they were just reference numbers (where I snipped). If I scroll down the list to find "16331A", the proper part number is listed below it. For future reference/anyone else reading this, proper part numbers are:

Thermostat - 90916-03100
Thermostat Gasket - 16346-17010
Water Temperature Sensor -  89422-35010 

I ended up calling a different Toyota dealership to get my quotes,etc. since the original one was taking so long. I was quoted roughly $23 excluding postage, and only a 3-4 day wait for a delivery from Melbourne. Sounded awesome to me so I went with that one

Hoonsy, I got 8.9L/100km. Travelled 383.2km for 34.4L. Includes a spirited club run over Mt Nebo and Mt Glorious and daily driving activities, work, shops etc mostly suburban. I will be keeping track over the next few tanks and will work out the average. Did you end up calculating yours? 

Testing a catalytic converter is easy, just need a mate who has a laser heat detection gun (most mechanic shops have them). Jack the car up, aim the gun at the cat then shoot and see the result. I'm not savvy on what OEM cats should run on these cars but as a general rule of thumb I've always considered above 700 degrees to be problematic. It shouldn't cost over $400 for a good exhaust shop to remove the current one and weld in a high flow anyway. That'd be my suggestion. The O2 sensor will help with your fuel consumption, they often get clogged up with carbon after 100,000k's anyway. 

Lumix
Hoonsy, I got 8.9L/100km. Travelled 383.2km for 34.4L. Includes a spirited club run over Mt Nebo and Mt Glorious and daily driving activities, work, shops etc mostly suburban. I will be keeping track over the next few tanks and will work out the average. Did you end up calculating yours? 

Read your post so went to the servo exactly 1km down the road and topped up even though I didn't exactly need it - keep in mind I always stop at the first click which results in: (16.59Lx100) / 156 = 10.6L/100km

That sorta sounds okay (some people said they were getting roughly that) but at least 65% of my driving on this tank has been highway travel (for work), with the rest just being street driving getting to work. No spirited runs or anything, and hardly ever revving it out (did maybe 2-3 pulls during the past week)

Took photo just as I was getting out to fill up for reference

Matts_SW20
Testing a catalytic converter is easy, just need a mate who has a laser heat detection gun (most mechanic shops have them). Jack the car up, aim the gun at the cat then shoot and see the result. I'm not savvy on what OEM cats should run on these cars but as a general rule of thumb I've always considered above 700 degrees to be problematic. It shouldn't cost over $400 for a good exhaust shop to remove the current one and weld in a high flow anyway. That'd be my suggestion. The O2 sensor will help with your fuel consumption, they often get clogged up with carbon after 100,000k's anyway. 

Unfortunately me and my mates are just kids/backyard mechanics so we lack any sophisticated tools. That, and $400 is a bit too much for me at the moment anyway, but I'll keep it in mind. Thanks Matt

Sorry, I clicked on the arrow thinking it took me to the last page but it took me to the second and thats what I was responding to haha.  I'm very much a backyard mechanic haha but I have friends who are legit mechanics who have these fancy tools. I'm sure a local exhaust shop would aim their gun at it for free if you were curious. Yea $50 is steep for me this time of year lol.

Matts_SW20
Sorry, I clicked on the arrow thinking it took me to the last page but it took me to the second and thats what I was responding to haha.  I'm very much a backyard mechanic haha but I have friends who are legit mechanics who have these fancy tools. I'm sure a local exhaust shop would aim their gun at it for free if you were curious. Yea $50 is steep for me this time of year lol.

Either that or they'll aim it, all gasp and start cheering, high-fiving being all like "We're gonna be rich!" and take all my money. Jokes on them, there's no money to take haha!

But yeah, I'm trying to keep buying/replacing parts to a minimum for now, just until I get a confirmed permanent work roster as I'm only a temp. at the moment