Save up to 15% with Adrian Flux insurance!

Technical mk1 punto temp gauge

Currently reading:
Technical mk1 punto temp gauge

M

MADJIB

New member
Joined
Mar 4, 2011
Messages
12
Points
3
just changed head gasket all fine except temp gauge not working. bought a new sensor made no difference, earthing the wire on sensor results in instrument full scale deflection so gauge seems ok. any ideas out there?
 
You may have also brought the one for the inlet manifold temp.

All three sensors look different. The two in the head has either red or black plastic and feed the gauge. The inlet manifold one has blue plastic and is for info for the ecu.

Did the gauge work before? Also when you did the headgasket did you do the thermostat?
 
thanks for the info. New sensor is different to old in that the body is larger and the socket required to fit it with is 21mm as opposed to 19mm. Neither seem to working. I have tested both with a voltmeter in boiling water and both produce a small voltage of approx equal value. Thermostat working fine it was replaced a month or so ago. Engine heats up fine fan cuts in and out as it should and heater all working. Really stumped with this one will play around with it again tomorrow, wish me luck lol
 
Just to mention some variants depending from punto models. Some of Puntos have three pin connector on coolant temp sensor, and some of than have two pin coolant temp sensor. two pin sensor is for models picking up sensor data only for ECU and only have warnning temp light on dash. three pin srnsor is in fact doubled two-pin coolant sensor where one signal goes to Ecu and other to temp-gauge placed into dash. into boiling water test coolant sensor should read 2500 ohms on 25 celsius and abt 120-150 ohms on boiling point 100 celsius (negative temp coeficient). hottest coolant less resistsnce in ohms. if you find some potentiometer of 2.5 kiloohms (2500 ohms) and connect instead this sensor you can made experiment compairing to ohmmeter. if you adjust potentiomrter to 120 ohms, Ecu should react and warning light and gauge have to read boiling. increase resistance on potentiometer should deactivate warning light and gauge should fall
sorry i wrote from mobile
 
cheers, sensor is on cylinder head and has only one wire connected via a spade terminal tried to get a resistance measurement but meter would not read, I'll try again in the morning
 
Sorry I see now thats MK1 s.
Resistance should be the same as later models 2.5k (2500 ohms) on 25C and 150 ohms on 100 C. for models with gauge in dash. If you have only warning light without coolant temp gauge on dash than instead coolant sensor in engine block you have temp-switch just for on/off bulb on 100C.
 
Last edited:
bit the bullet and bought another sensor from fiat dealer. still no joy, asked dealer for advice and they kindly lent me a mechanic for 15 minutes. He too was baffled but did notice that supply to sensor was only 7.5V. Looks like a wiring problem so I'll have to re-wire from gauge to sensor. Daughter has the car back for now so I'll get round to it when she next visits. Thanks for the help guys much appreciated, I'll let you know how I get on.
 
still no joy with temp guage. replaced wire from sender to instument panel, now replaced instrument panel still nothing. Gauge on replacement panel moves about 2mm, which is furhter than original. I hve now tried every combination of three sensors two instrument panels including swapping gauges between panels and still no temp gauge. Everything alse works fine fans cut, in coolant is clear heater working fine, I am now really stumped if anyone can shed some light on this it would be much apperciated.

cheers
 
Have you checked the hole were the sensor goes in? Mite just be a bit of crap has blocked the sensor hole in when you flushed the cooling system? Just a wild gess.
 
thanks for the wild guess sensor hole is clear and coolant is lost everytime I remove it. Coolant is not showing any signs of contamination.
 
I fitted dash with heating gauge on my mk1, rpm gauge sorted, just could you tell me please, which particular sensor needs to be changed to make that heating gauge work. I have mk1 1.2 8v engine. At the moment my gauge also comes 2 mm up, when turn car on, and never goes further.

thanks
 
Mar4ix, Not sure you are asking the right person here. Any way sensor is located beside the dipstick screwed into engine block. As previously stated in this thread sensor should have a black surround covering the spade connector. Well mine has this but still won't work. I will be scowering local scrappies next for a couple of sensors as I have paid out more than enough on this problem so far. It has to be something simple but buggered if I can find it.

good luck with yours
 
MADJIB said:
Mar4ix, Not sure you are asking the right person here. Any way sensor is located beside the dipstick screwed into engine block. As previously stated in this thread sensor should have a black surround covering the spade connector. Well mine has this but still won't work. I will be scowering local scrappies next for a couple of sensors as I have paid out more than enough on this problem so far. It has to be something simple but buggered if I can find it.

good luck with yours
Click to expand...

Thanks for answer, ill try also replace that sensor , let you know how it'll work. good luck with hunting for right sensors.
 
Yes i did "earthing the wire on sensor results in instrument full scale"
And yes I got the right sensor - I even try with 3 diferent right sensors.
No respons at all
 
flisko said:
your temp wont rise instantly when you start car, maybe all your 3 sensors are for car with only a light, you need to get sensor for temp gauge or else needle wont move, is wire plugged on the sensor
Click to expand...

flisko - first thank you for trying to help.
But I write just here because I have tried everything suggested in this and other threads.
I am aware of the engine must be warm before the gauge rises.
I am also absolutely sure the 3 sensors is for a car with gauge and not for lamp.
This is easily tested with ohm-meters. Sensor for lamp is a simple contact-sensor - sensor for gouge is not-it register resistance at the changing temp.
If you read this forum and the web in general it is quite obvious that I'm far from the first one with this problem but not a single place I have found the answer to the problem.
I have had the car for about half a year now and have made very mechanically on it and the longer I've had it, the more I think:

What a bad car Fiat Punto MK1 is .....
 
You must log in or register to reply here.

Similar threads

GTAntoni
Technical Punto GT boost gauge
Replies
1
Views
248
Steve gt
Steve gt
R
General Searching For Mk1 Punto Cabrio
Replies
2
Views
229
Roberto90
R
J
Technical Brake Master Cylinder Punto Mk1
Replies
3
Views
237
Chris parry
Chris parry
J
General Punto Cabrio mk1 Seal Gasket
Replies
2
Views
238
jmariano
J
Leki99
  • Question
Technical Punto mk1 not running good
Replies
4
Views
492
varesecrazy
V
Back
Top