Idling issues - blue temp sensor

[Rabs]

Hi,

I am having issues with idling when hot and cold. I have read the wiki and have checked the rubber boot and there seems to be no leaks. I have then used a multimeter on the blue temp sensor....when it is cold I had a reading of about 1630 and 309 when warm. From looking at the wiki the cold reading is wrong. Should I get this replaced? I also tried running the engine with the connector to wiring loom not attached when warm and it still seemed to not run right.

Is this reading far enough out that I should place the blue temp sensor?

Thanks

[daimlerman]

I would suggest that your blue sensor is OK,but did you test at the ECU plug as well as at the sensor?
This rules out a possible wiring fault....

Another very sneaky cause of wrong fuel/air ratio is the small blanking plug on the bottom of the throttle body,the slightest split here plays havoc with the slow running.

[Rabs]

Thanks for the info, how do you test at the ECU?

[Grrrmachine]

how do you test at the ECU?

I have read the wiki...

[HairyScreech]

Testing
Testing the actual Plug is a relative simple affair, requiring a multimeter.

Locate the Plug and remove its loom connection
Set your multimeter to measure resistance (Ohms)
From cold, expect a reading in the region of 3500-4000 Ohms. Any more or less than this is not a huge issue.
Reconnect, warm up the engine, and retest
From hot, expect a reading in the region of 330 Ohms. If your Blue Plug has not changed its resistance significantly, then it is at fault and should be replaced.
However, for Blue Plug-related issues, it is also important to test that the information is reaching the ECU. To do this:

Locate the ECU and disconnect its plug.
Repeat the Blue Plug test, this time putting your multimeter electrodes onto pins 24 and 45 of the ECU.
Confirm that the readings you got at the ECU are the same or similar to what you read at the Blue Plug.
If the readings differ, then the most likely cause is corrosion of the C191 plug.

[Rabs]

How do you test at the ECU? Do you unplug ECU and check with a multimeter at the pins on plug that normallt connects to ECU?

[BenHar]

test that the information is reaching the ECU. To do this:

Locate the ECU and disconnect its plug.
Repeat the Blue Plug test, this time putting your multimeter electrodes onto pins 24 and 45 of the ECU plug.
Confirm that the readings you got at the ECU are the same or similar to what you read at the Blue Plug.
If the readings differ, then the most likely cause is corrosion of the C191 plug.

[Rabs]

Do you need to have the ignition on? When I tried today I had a reading as expected at blue temp sensor but no reading at all on the ECU plug when connecting earth lead (black) to pin 24 and red to pin 45. Wasn't sure if I was doing it right.