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[Jukeboxnut]

I suspect that the coolant temperature sensor on my 2.2 petrol estate is reading incorrectly as the fuel consumption appears to be too high and there is the feeling that the engine is running too rich (slight pulse during steady speed cruising as if the coke is slightly engaged).  How difficult is it to test this and change it if necessary?  I have a multimeter to read the resistance if necessary.  It seems to be very difficult to see this sensor without a mirror let alone test and/or replace it.  Has anyone here actually replaced the CTS?  Any help with this would be most welcome.  The temperature gauge on the dashboard is reading correctly (I have compared the reading with a calibrated thermocouple at work) but I believe that there is a seperate sensor for this.

[Kevin Wood]

Yep. ECU and dashboard sensors are separate. There are a couple of options:

1) Get someone with a Tech 2 to tell you what temperature the ECU thinks it's at, compare with dash gauge.

2) Measure sensor resistance both hot and cold. If it's difficult to get to the sensor, you could always have a look what pins on the ECU it connects to and measure there.

I don't have the values for that sensor but typically a couple of hundred ohms hot and over 1000 cold would be normal. Will have to check the spec for the Omega sensors.

Kevin

[tunnie]

you have a 2004 2.2???

Is it a 54 or 04 plate??

Must have been a late registration, i have only seen plod 2004 plated Omega's.

[mkaminski100]

I always thought that there are only 2 sensors in 2.0 and 2.2 - one at the back of the engine (ECU and dash) and one in cooler (to turn the fan on).
If there is third one, where is it and what the one on the back for?

I’ve connected an OpelScanner device and temp in mine is 80-82 when driving and 82-87 when the vehicle is not moving. When the temperature reaches 87, thermostat opens and it drops to 82-84.
When the engine is cold it shows 10, while outside temp is 7.
Is it normal for these engines or my sensor is failing?


Jukeboxnut – where are you from? I’m from Reading. I can have an OpelScanner – PC cable that can check your engine temp and few other things (not that sophisticated as Tech2, but helpful [ch61514] )

[Jukeboxnut]

Thank you for the quick responses to my post about the CTS.

The car has an 04 plate, registered on 02.04.04 and I bought it in December from the leasing company who owned it from new so I guess it must be one of the last 2.2 models made now with 90,000 miles under its belt.

If I remember correctly there are three temperature sensors in total on the 2.0 and 2.2 engines.  Two on the rear of the engine block, one which connects to the dashboard gauge and one that feeds the ECU (which I suspect may be reading low causing the poor fuel consumption on my car). The third sensor is on the radiator (I think) which switches the cooling fan.

I'm from Bognor Regis not too far from Reading and in fact I'm considering buying an OpelScanner or similar device myself as I cannot paperclip this car as I could on my previous 2.0 Omega and it would be useful to be able to perform the basic tests on the various sensors etc.  Mind you I need to buy a laptop first and all the new ones seem to be USB port connection only which may limit the  application somewhat.

[mkaminski100]

I might be wrong but I think that there are only 2 cables comming from the back of the engine. One sensor is under the coil pack, second in radiator.
I have a USBtoCOM adaptor and it works fine. I had to switch COM preferrences of this port to COM2 and now it works fine. My cable is about 2-3 meters long and you can always extend it.
How much do you have to pay for and OpelScanner in UK and what it can do?
I might be going to the seaside on Sunday so if you tell me some places that I can visit around Bognor Regis, I will check your car dusring my visit Is it fair?

[Jukeboxnut]

Hi mkaminski100,
Thank you very much for kind offer to try and visit on Sunday, that would be more than fair.  I notice that you have also posted about poor fuel consumption on your 2.0 auto, it is possible that we may have the same fault and it would be interesting to compare the various sensor readings of the two engines (I am assuming that the 2.2 and 2.0 engines use the same sensors and ECU system).  Also I believe that running on LPG gives less mpg than running on petrol, is this true?

I had a look at the back of my engine earlier this evening using a mirror and small torch and there are definately two sensors next to each other at the back of the cylinder head.  One is small with a single wire attached which I presume goes to the dashboard gauge and the other is larger with two wires which must supply info to the ECU and which I suspect may be on the extreme edge of specifcation causing a richer mixture than necessary.  It is virtually impossible to touch them unless it is easier to reach them from under the car.

I do not know the price for the OpelScanner, I read a discussion on the various types available and that name was mentioned as a useful option to the usual Tech 2.  I only bought this car two months ago so I am still considering the various options for code reading so I do not know what the OpelScanner can do.

I actually live in Pagham which is at the extreme west of Bognor, about a mile from Pagham harbour which is a large nature reserve, reaching almost around to Selsey.  All Bognor has really is the seafront but there are many places to visit around here such as Chichester (8 miles), Arundel (10 miles) or Goodwood (8 miles) etc.

My email is rockolacolin@yahoo.co.uk if you want to contact me for my home address and how to get here.

Colin