another blue temp' sensor question

[Cloggy Saint]

What's the deal with these things, are they either good or knackered? Is there any middle ground, ie not working very well?

[kam-325i]

No real middle ground, if it is giving the wrong temp reading to the ECU, then its kanackerd...

[Simon]

If in doubt, just change it, they can make a lot of difference!

[Cloggy Saint]

I'll change anything if it improves my current 18mpg average

[Brianmoooore]

Blue sensor can fail leaving the ECU thinking the engine is cold all the time (high fuel consumption), it can fail leaving the ECU thinking the engine is hot all the time (difficult starting and hesitation untill hot), or it can only gpo slightly out of spec, causing only slight symtoms.
From my own measurements, at full engine working temperature, the sensor should have a resistance of about 200-250 ohms.

[Grantley]

I changed the blue sensor to try and cure running and idle problems, it made a big difference to way the car starts and runs when cold. For Ԛ£11.75 inc VAT and being very easy and quick to fit I would'nt be that bothered if that hadnt been the problem and if nothing else you've eliminated one possible problem cheaply.

[Cloggy Saint]

If the ecu thought the engine was cold all the time, wouldn't it run like a dog due to flooding, and not idle?

[Brianmoooore]

If the ecu thought the engine was cold all the time, wouldn't it run like a dog due to flooding, and not idle?

Yes depending on how cold the ECU thinks the engine is.

[DemonDaz]

How do you get the blue sensor off? I couldn't get a spanner to it.

[charlE30]

How do you get the blue sensor off? I couldn't get a spanner to it.

I did mine when I had the manifold off, wouldn't know how with the manifold on though I was suprised how much of a difference it made to fuel consumption

[dazleeds]

its fiddly but im sure it can be done with manifold on

sure i did mine on old car this way

spanner on an angle to loosen slightkly then twist it out by hand

[Simon]

Yeah, as Daz said, it can be awkward, but can be done, it only needs to be turned slightly, and then it can be undone by hand.

[Brianmoooore]

Didn't someone post that the OE spark plug tool would remove it?

[GDBN]

Is the blue temp sensor for a 325 part no .13621709966 ??
Just want to check before I order a new one.
Thanks,

G

[Jami]

I recently changed the blue temp sensor on my 320i. Managed it by shifting the wiring rail which connects to the injectors. Just unplug it and move it toward the bulk head, i had to remove the rocker cover breather to do this.

Now i would not endorse this but i use a OE plug spanner, as it is just about deep enough and does the job.

Hope this helps. It was worth the trouble as the car starts perfectly cold, warm or hot, and runs alot better.

[DemonDaz]

What is an OE plug spanner? And where can one be obtained?

[Cloggy Saint]

What is an OE plug spanner? And where can one be obtained?

Original Equipment plug spanner. Probably comes with the E30 tool kit.

[H-M3]

ive changed my one little while ago but my car seems to have problem starting in the morning?? could the blue sensor be a dud one?

[Sharknose3]

I changed my blue sensor recently,

The easiest way to do it is to remove the brown sensor first, then you'll have easy access to the blue one with an open ended spanner.

Fit both sensors, top it up and bleed the system as required,

Sharknose

[DemonDaz]

I removed the brown sensor but still couldn't get a spanner at the right angle to get the blue one without hitting something else?

[Brianmoooore]

I removed the brown sensor but still couldn't get a spanner at the right angle to get the blue one without hitting something else?

I assure you, it can be done.

[DazzyA]

Fit both sensors, top it up and bleed the system as required,

Sharknose

Do you need to drain coolant then?

[Brianmoooore]

There will be a small amount of leakage, but as long as you leave the old sensors just screwed in a couple of turns untill you are actually ready to screw in the new one, then it will be minimal.

[DazzyA]

Thanks again Brian, hadn't considered that eventuality.