Water temp sensors - what are the symptoms if failed?

As above?

Where is it located by the way?
Also would a GT one fit a 98 Glanza one? Because the camskill says there're 2 different versions with a massive price difference, but looks about the same!


Thanks
Reps given as usual!

Paul

anyone? Is it next to the thermostat?

glanza and gt ones are different. you could possibly cut and join the wires to get a gt one to work but then you would need a gt plug off a loom.

it will be on the thermostat housing. 3 wires for the glanza and 2 wires for the gt

dac69er said:

glanza and gt ones are different. you could possibly cut and join the wires to get a gt one to work but then you would need a gt plug off a loom.

it will be on the thermostat housing. 3 wires for the glanza and 2 wires for the gt

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According to the CAmskill - the glanza till 97, is same as GT one. and Only late 97 - 99 got different sensor - which cost 3 times more than the GT one..... Anyway how would I know if it's failed or not??? How to undo it? Just unscrew it? Also mine is an Auto - if that makes any difference, but I know for a fact that the Auto ECU is taking data off that sensor.

symptoms vary. they range from poor starting from cold to poor running when hot. generally it tends to run ok at either hot or cold engine temps but not both.

if your sensor is 3 wire then you need a 3 wire more expensive one. if its 2 wire then the cheaper one will be the one you need

dac69er said:

symptoms vary. they range from poor starting from cold to poor running when hot. generally it tends to run ok at either hot or cold engine temps but not both.

if your sensor is 3 wire then you need a 3 wire more expensive one. if its 2 wire then the cheaper one will be the one you need

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Right, thanks for that. Is there any other way to test it? say with the multimeter? correct volatage? anything...

you can measure the resistance of it at different temperatures. as i only have a GT the values of my sensor may be different if you have a different sensor.

what problems are you having?

It runs really bad sometimes, could be good, then in 10 min really bad - like a massive loss of power, or retarded ignition. Then it could be ok after a while.... No error codes, replaced the map sensor - helped a little bit, but didnt fix the problem. Compression is good, timing is good, fuel pressure checked - good. Normally it's good when the engine is cold, then it gets worse especially in 2nd...

on boost or off boost or does it make any difference? could be a small vac leak that only sometimes leaks???

dac69er said:

on boost or off boost or does it make any difference? could be a small vac leak that only sometimes leaks???

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Nothing to do with boost, it can show full boost, but get no torque at all in 2nd gear, would take about 10sec to get from 40 to 60..... with a pedal to the floor...... And some time later it could be fine, or it can start fine and quick.... Have no idea what is wrong with it... I was told some sensor might play up - resulting in to my problems, trying to figure out!

Vac leaks - I'm talking about complete loss of power - worse than N/A Starlet, almost impossible to overtake anyone! And I can see full boost on the gauge, and it spools very quickly.

Any ideas would be appreciated!

Paul_JJ said:

Any ideas would be appreciated!

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Many issues to consider for timing - eg.
Too much heat on the air intake sensor will retard timing. ( Plus there is intentional lag built into the stock sensor )
Too much fuel will retard timing around spool time. ( eg check your soft intake piping is not closing-up under wind load? )

Also poor spark can effect torque.

Rev said:

Many issues to consider for timing - eg.
Too much heat on the air intake sensor will retard timing. ( Plus there is intentional lag built into the stock sensor )
Too much fuel will retard timing around spool time. ( eg check your soft intake piping is not closing-up under wind load? )

Also poor spark can effect torque.

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The timing is fine, when idle.
Sparks good condition, most of the ignition related parts brand new
Front mount does the job, cool side is really cold
Fuel Pressure has been checked and set up to a standard boost levels - running standard boost to eliminate other possible issues.

Paul_JJ said:

would a GT one fit a 98 Glanza one? Because the camskill says there're 2 different versions with a massive price difference, but looks about the same!

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You can fit the old type sensor, but you'll need to chop your current connector off and fit one that suits the old type sensor.

The early type 2 pin sensor is almost generic, that's why they're cheaper. Toyota obviously thought about this at some point and decided to make their own version with a different connector, which meant you had to buy a genuine part at a ramped up price when the old one failed.

Paul_JJ said:

Nothing to do with boost, it can show full boost, but get no torque at all in 2nd gear, would take about 10sec to get from 40 to 60..... with a pedal to the floor...... And some time later it could be fine, or it can start fine and quick.... Have no idea what is wrong with it... I was told some sensor might play up - resulting in to my problems, trying to figure out!

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Does this only happen when you've got the throttle wide open? Or does it happen at part throttle also?

Does the engine misfire or surge? or is the power delivery just generally flat?


The voltage reading at the THW terminal of the ECU when the fault occurs would be useful to identify if the coolant temp. sensor is at fault. 0.5v would be a good reading, less than 0.2v or more than 0.9v would require further investigation.

The voltage reading at the VTA terminal of the ECU along with the throttle position when the fault occurs may also be useful to identify if the TPS is at fault.

Other possible causes could be a fuel supply issue such as an intermittent fuel pump or regulator issue.

Texx said:

You can fit the old type sensor, but you'll need to chop your current connector off and fit one that suits the old type sensor.

The early type 2 pin sensor is almost generic, that's why they're cheaper. Toyota obviously thought about this at some point and decided to make their own version with a different connector, which meant you had to buy a genuine part at a ramped up price when the old one failed.




Does this only happen when you've got the throttle wide open? Or does it happen at part throttle also?

Does the engine misfire or surge? or is the power delivery just generally flat?


The voltage reading at the THW terminal of the ECU when the fault occurs would be useful to identify if the coolant temp. sensor is at fault. 0.5v would be a good reading, less than 0.2v or more than 0.9v would require further investigation.

The voltage reading at the VTA terminal of the ECU along with the throttle position when the fault occurs may also be useful to identify if the TPS is at fault.

Other possible causes could be a fuel supply issue such as an intermittent fuel pump or regulator issue.

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Thanks a lot Tex.

The throttle position wouldn't make much difference when it's happening. There is no indication of a misfire or surge whatsoever, the RPM is very stable, the idle is spot on.

The FPR has been replaced to a Sard one [bought used] a few months ago, the pressure is standard at the moment, boost is standard. Could that be a faulty FPR?

It's just flat, absolute loss of power, impossible to overtake other cars.

The fuel pump is standard [original] - could be something to do with that.

How do I find that THW terminal? Any pics? Also VTA terminal?

I wonder if that could be the gearbox issue? Also the water sensor is related to the gearbox ECU - which can make my life harder, I assume. Can the faulty Knock Sensor cause that?

Forgot to mention that I have very bad MPG - around 20-30 miles per a quarter of a tank!

Hi Paul,

I've read the above and as you can see there are a number of possibilities.

Just on your last comment, what makes you think your knock sensor is faulty?

Jay

Hi Jay

I just assume that having faulty sensor would result in bad MPG which I currently experience! I always run 99 RON by the way.

I've just had a drive - started fine, once the engine warmed up I had a decent torque in 1st, then a short drive doing 30mph, then pushed the pedal to the floor, but experienced the same acceleration as if the pedal was slightly pressed, the gears changed at 3-4K rpm, I was having a full boost, but couldn't really feel it, also if half throttle then it would be slower a little bit.

Jay you have an Auto - you know how it feels when the engine is cold and you want to go fast the gearbox won't let you and will change the gear early - sort of similar to that. Also you know when you say in 3rd and doing 40mph - you want to overtake someone and the gearbox will drop the gear to 2nd - well in make case it doesn't drop the gear anymore, unless I change it manually.

The engine was cold and the RPM went to 1400 as it's normally does on the cold engine! I wonder if the water temp sensor is playing up and the gearbox thinks that the engine is cold - resulting in cold mode run. The whole car feels retarded though, It doesn't feel responsive anymore, even when it runs OK.

I know it can be many things but I want to pinpoint the actual problem as I can't simply buy all the new sensors and replace the fuel pump at the same time.

I'm assuming you've already checked for both engine and transmission fault codes?

Paul_JJ said:

you know when you say in 3rd and doing 40mph - you want to overtake someone and the gearbox will drop the gear to 2nd - well in make case it doesn't drop the gear anymore, unless I change it manually.

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I would check the voltage range output of the TPS to rule it out as a possible cause.

You'll need a multimeter with some 'modified' probes, twisting a paperclip onto the end of each probe works well, or twist a paperclip onto a couple of lengths of wire that you can connect to the meter probes. Find the middle connector of the ECU, look at the wire side of the connector with the clip facing up. The terminals you need to test are 9 and 10, the furthest right 2 terminals on the bottom row.



Using the paperclip modification (by pushing the paperclip into the wire side of the connector) connect the black probe of the multimeter to terminal 9 (E2 sensor ground) and the red probe to terminal 10 (VTA - TPS output signal), ensure the 2 connections cannot touch each other (use some insulation tape if needs be), set the multimeter to 20v DC and then turn the ignition ON. (The connector must remain plugged into the ECU)

You should see a reading on the meter of between 0.3v - 0.8v. Next slowly press the throttle pedal and watch the voltage reading on the meter, you should see a linear increase in voltage as the pedal moves closer to the floor. With the throttle pedal on the floor you should expect to see a voltage reading between 4v - 5v.

If the voltage reading suddenly drops whilst testing without the throttle pedal being released, then there could be a fault with the TPS or the TPS circuit.

The main purpose of this test is to confirm the TPS ranges correctly and to identify the TPS output voltage when the throttle is wide open.

I would be looking at the TPS first if it's an acceleration related issue. It can be a common issue on the manuals from what I've seen and could give the trouble you are describing without throwing a fault code.

The knock sensor will throw a warning lamp on and r'tard your timing if it sees trouble. That doesn't appear to be happening from the sound of it.

Jay