Temp Sensor

[Guest Andy Mack]

Im getting pants MGP and someone said it might be the temp sensor. Is there a way i can test it to see if its that this is at fault?

 

Is there anything else that could cause bad MPG?

 

And its not just my driving style!

 

Cheers

 

Andy Mack

[pug_ham 244 3 Cars]

The only test I know of is the one included in the full fuel injection system test in the Haynes joke book;

10 Pull off the temperature sensor connector & connect an ohmmeter across the two terminals on the sensor.  If the reading is infinity then renew the sensor.

 

Graham.

[Guest Andy Mack]

where does it tell you that in the haynes book? I couldnt find anything on it.

[pug_ham 244 3 Cars]

It will depend on what style of Haynes you have, if you have the newer ones with the spanner ratings next to the write up then I don't know where it will be except for in the same section, fuel & exhaust systems, fuel injection system, complete test. Page 95 section 26 in the older style that I have here, itme #10.

 

Graham.

[KRISKARRERA 2 1 Cars]

The only test I know of is the one included in the full fuel injection system test in the Haynes joke book;

10 Pull off the temperature sensor connector & connect an ohmmeter across the two terminals on the sensor.  If the reading is infinity then renew the sensor.

 

Graham.

So what should it be reading then?

[pug_ham 244 3 Cars]

Anything less than infinity, the lower the better I'd guess.

 

Graham.

[KRISKARRERA 2 1 Cars]

I'll test mine soon I think. Oh I take it it should be tested cold?

[CJ_2_0_5 0]

The resistance should be roughly as follows :-

 

@-10°C - 8200<R<11000

@+20°C - 2280<R<2720

@+80°C - 290<R<370

 

You should really check it at the ECU connector to be sure that there is not a high resistance connection or something between the ECU and the sensor.

 

Cheers

CJ

[Zoldalma 1]

Some more info:

Temperature  Resistance 
+10 Celsius   8.2 - 11.0 KOhm 
+20 Celsius   2.28 - 2.72 KOhm 
+40 Celsius   1.0 - 1.5 KOhm 
+60 Celsius   600 - 700 Ohm 
+80 Celsius   290 - 370 Ohm 
+100 Celsius 180 - 220 Ohm

[KRISKARRERA 2 1 Cars]

I've got a spare sensor right here and i'm just testing resistance with my multimeter...... currently at about 1000 ohms, here in my bed room at room temp. How the hell can I test it accurately? Put it in boiling water??

[Guest Andy Mack]

how do i know where it is? what does it look like? does anyone have a picture? Is it kind of similar to the thermo switch that goes in the radiator?

[pug_ham 244 3 Cars]

 

It's the blue connector that's ringed.

 

That is from a phase 2 thermostat housing, if you have a phase 1 you should have a coolant housing underneath the dizzy that has a short hose from the side of the thermostat housing & another from the back that goes to the heater hose feed at the bulkhead & the temp switch is on the side of this.

 

Graham.

[Guest Andy Mack]

where is it? Can you see roughtly where it is in this picture?

 

This is if your looking down from the top with the air filter removed.

 

[Rob_the_Sparky 9]

Not only can you see roughly where it is, you can see the sensor!!!! (just left of the ignition leads, blue connector covered in oil)

 

Rob

[Guest Andy Mack]

cheers. So can i just unscrew it and test it? Or can i just test is where it is?

[pug_ham 244 3 Cars]

Test it where it is, if you unscrew it then you'll drain the coolant if it is full.

 

Graham.

[Guest puggti]

Are these sensors a lot of money, isnt it just worth buying another one?

P.s. after 100k shud i replace it?

[Guest Andy Mack]

So where do i connect the multimeter too then on it? Sorry im a bit useless.

[pug_ham 244 3 Cars]

So where do i connect the multimeter too then on it? Sorry im a bit useless.

Remove the plug & connect the multimeter across the pins of the sender iirc.

 

Graham.

[Guest Andy Mack]

but you said if i take it out then coolant will go everywhere? Am i being a muppet? Do you mean take off a cap or something?

[Guest stevec205gti]

Pull the connector off the end of it and they'll be two pins - just measure the resistance across them