Engine Coolant Sensor (green one)

1. RAF L-plater Joined: Apr 2009 Posts: 53

   #1 9th July 2010, 17:46

   Now I'm sure this is the fault on my car because I pulled it off whilst the car was running, and it made no difference to the lumpy idle speed.
   
   Would that be a good diagnosis?
   
   And... where is the cheapest place I could get one from?
2. raunchz Saxperience Addict Joined: Jul 2005 Solihull / Bournemouth Posts: 14233 2015 Lapiz Blue Golf R

   #2 9th July 2010, 18:09

   measure the resistance across it
   
   Don't buy cheapest, I'd buy from Citroen
3. BobCm Forum Section Moderator Joined: Apr 2009 Orpington Posts: 1406 My son drives a Poseidon Blue Saxo Mk2 1.6i VTR.

   #3 9th July 2010, 19:06

   Hi,
   
   The operation of this sensor depends on the year of the Saxo and its wired up differently based on the year of manufacture. Later models have an additional blue temp sensor.
   
   The green one can just drive the coolant temperature warning light. But if it is wired for measuring temperature then do as Raunchz says:
   
   Measure the resistance, it should come down as its temperature goes up.
4. RAF L-plater Joined: Apr 2009 Posts: 53

   #4 9th July 2010, 19:32

   Mine has a blue one too, which I believe is the oil temp sensor. I've recently replaced that and it made no difference to the lumpy, up and down revs. The car has had a replacement single point injection unit which included stepper motor, so I know it isn't that. It's using a lot of fuel. about £10 to do about 40 miles. I don't have a temp guage since it's a 1.1 so I've got no idea what the engine temp is. But I've got no warning lights for ECU or Oil Temp.
   
   I would have thought the car would go mad if I unplugged the Green Coolant temp sensor from the side of the block whilst the car was running, but there was no change in how it idled whatsoever, that's why I had the assumption that it wasn't working.
5. BobCm Forum Section Moderator Joined: Apr 2009 Orpington Posts: 1406 My son drives a Poseidon Blue Saxo Mk2 1.6i VTR.

   #5 9th July 2010, 19:42

   Only the VTS has an oil temp sensor. From what you've tried, the next prime suspect would be the oxygen sensor.
6. raunchz Saxperience Addict Joined: Jul 2005 Solihull / Bournemouth Posts: 14233 2015 Lapiz Blue Golf R

   #6 9th July 2010, 19:56

   the blue one near the green sensor is the dash coolant temp sensor.
   
   The oil temp sensor is in the sump.
   
   Just measure the resistance of both the green and blue sensors
7. lisavts Infrequent Poster Joined: Mar 2004 Stocksbridge, Sheffield Posts: 182 Mercury Grey VTS 1998

   #7 9th July 2010, 20:20

   the green one is the fuel injection temp sensor part number 1338a7 £26 citroen or £11 ebay...
8. raunchz Saxperience Addict Joined: Jul 2005 Solihull / Bournemouth Posts: 14233 2015 Lapiz Blue Golf R

   #8 9th July 2010, 21:22

   For that price I'd go for a Citroen one - unless the manufacturer of them in the same
9. RAF L-plater Joined: Apr 2009 Posts: 53

   #9 9th July 2010, 21:44

   Now I'm more confused...
   
   
   
   This is a pic of the sensors. Sorry it's rather dark since I took it only a few minutes ago and the battery was nearly dead on my camera so the flash would not work. I'm assuming the top one (in green) is the coolant temp sensor. The lower one is what? There have been a few conflicting responses as to what it is. It has been replaced nonetheless. The upper green one is the one I unplugged with no resulting change in characteristics whilst the engine was running. Is this the one more likely to cause lumpy running?
10. RAF L-plater Joined: Apr 2009 Posts: 53

    #10 9th July 2010, 21:46

    I know it seems a good angle to get said sensors in a picture, but most of the plastic parts of the engine are in the boot, which allowed me to get a clearer pic. The engine bay is due for a good clean, so I have been removing all the easy parts that I can.
11. raunchz Saxperience Addict Joined: Jul 2005 Solihull / Bournemouth Posts: 14233 2015 Lapiz Blue Golf R

    #11 9th July 2010, 21:52

    the green one is the ecu coolant temp sensor
    
    im pretty sure the blue one is the dash coolant temp sensor - the dash on the 8v's doesn't have an oil temp gauge
12. BobCm Forum Section Moderator Joined: Apr 2009 Orpington Posts: 1406 My son drives a Poseidon Blue Saxo Mk2 1.6i VTR.

    #12 9th July 2010, 22:54

    An overview of the Saxo TU9M (1.0) and TU1M+ (1.1) cooling system with and without air conditioning.
    
    Figure : b1gp030p
    B1GB0GP0
    [Note - the colours of the sensor connectors described above are WITHOUT the wiring connector in your photograph plugged in.]
    
    
    Sensors
    
    2 - Thermal switch temperature sensor lights the temperature warning light at 118 degrees celcius
    3 - Temperature sensor for the fuel injection system [and the temp gauge if your car had one]
    4A - Temperature sensor for the cooling fans with air conditioning; twin speed cooling fans: speed 1 at 96 degress speed 2 at 101 degrees
    4B - Temperature sensor for the cooling fans without air conditioning; cooling fan operates at 97 degrees celcius
    
    *** How about describing the problem you have in a little more detail? ***
    as the operation of these sensors may be irrelevant to YOUR problem as unplugging the green one does NOTHING
13. RAF L-plater Joined: Apr 2009 Posts: 53

    #13 10th July 2010, 00:11

    Quote:

    Originally Posted by BobC An overview of the Saxo TU9M (1.0) and TU1M+ (1.1) cooling system with and without air conditioning. Figure : b1gp030p B1GB0GP0 [Note - the colours of the sensor connectors described above are WITHOUT the wiring connector in your photograph plugged in.] Sensors 2 - Thermal switch temperature sensor lights the temperature warning light at 118 degrees celcius 3 - Temperature sensor for the fuel injection system [and the temp gauge if your car had one] 4A - Temperature sensor for the cooling fans with air conditioning; twin speed cooling fans: speed 1 at 96 degress speed 2 at 101 degrees 4B - Temperature sensor for the cooling fans without air conditioning; cooling fan operates at 97 degrees celcius *** How about describing the problem you have in a little more detail? *** as the operation of these sensors may be irrelevant to YOUR problem as unplugging the green one does NOTHING

    If you read my first post it said "Lumpy Idle Speed" so I don't understand how you cannot read that in any more detail! I can post a vid if you want of the engine idling, but that will have to wait till tomorrow given it's past midnight.
    
    I also mentioned high fuel consumption. Anything else you want to know I am more than willing to provide details... I thought providing a photo was quite good compared to most problem threads. I don't see what problem you have with my question?
14. RAF L-plater Joined: Apr 2009 Posts: 53

    #14 10th July 2010, 00:14

    It was on this forum ages ago when I read a thread that mentioned unpluging the green one whilst the engine was running and if that had no effect if basically proved that the sensor was at fault... I will try and find it if I can but I doubt it will be tonight...
15. RAF L-plater Joined: Apr 2009 Posts: 53

    #15 10th July 2010, 11:31

    So am I right that the car, under normal circumstances would kinda go mad and rev up and down with the coolant sensor unplugged whilst the car is running?
16. RAF L-plater Joined: Apr 2009 Posts: 53

    #16 10th July 2010, 16:17

    I've replaced the green sensor anyway as it was only cheap, I'll have to wait to see what MGP difference it makes if any.
    
    BUT I have another problem. Here is a pic of the engine.
    
    
    You can see a disconnected pipe resting near the bottle for the brake fluid. When I put this back where it should be on top of the little air box thing, the car won't start! Any ideas?
17. raunchz Saxperience Addict Joined: Jul 2005 Solihull / Bournemouth Posts: 14233 2015 Lapiz Blue Golf R

    #17 10th July 2010, 16:23

    Quote:

    Originally Posted by RAF It was on this forum ages ago when I read a thread that mentioned unpluging the green one whilst the engine was running and if that had no effect if basically proved that the sensor was at fault... I will try and find it if I can but I doubt it will be tonight...

    Might be th map sensor you're thinking about?
18. RAF L-plater Joined: Apr 2009 Posts: 53

    #18 10th July 2010, 16:30

    Does a 1.1i have a MAP sensor?
19. RAF L-plater Joined: Apr 2009 Posts: 53

    #19 10th July 2010, 17:34

    
20. RAF L-plater Joined: Apr 2009 Posts: 53

    #20 10th July 2010, 17:34

    Argh no edit button.... click to play ^
21. RAF L-plater Joined: Apr 2009 Posts: 53

    #21 12th July 2010, 00:50

    Bump... no one answered my question on wether a 1.1i has a MAP sensor or not...
    
    If it does... where would it be?