What does this pipe do?

[JamesV6CDX]

your coolant temp sensor is goosed and will play hell with the fuelling (and hence lambdas!)

Like this one?

https://www.eurocarparts.com/p/starline-coolant-temperature-sensor-22488006s

Almost certainly not.

That's to say the guide applies to the 2.5/3.0.

You want this one.

https://www.ebay.co.uk/itm/283556554341

Are you sure mate? That's a square plug which I think was phased out on facelift models. Mig's Omega will have the later style oval connectors

[JamesV6CDX]

Was this immediately after start?

It's showing an ambient outside temp of 9degrees and the coolant temp at 42 degrees!

If this was immediately upon starting, then your coolant temp sensor is goosed and will play hell with the fuelling (and hence lambdas!)

Yes. You can see by the RPM, it hadn't even settled down to 600RPM.

In that case, your coolant temp sensor is totally ficked!

Incorrect CTS readings will play hell with some of the other sensors - particularly lambda, and will affect the fuelling.

It's a known problem which needs to be fixed, and is highly likely to be linked.

It could very well be a £10 solution

[Migalot]

your coolant temp sensor is goosed and will play hell with the fuelling (and hence lambdas!)

Like this one?

https://www.eurocarparts.com/p/starline-coolant-temperature-sensor-22488006s

Almost certainly not.

That's to say the guide applies to the 2.5/3.0.

You want this one.

https://www.ebay.co.uk/itm/283556554341

When I put my car details in on the eBay one it says it's not compatible, but the Eurocarparts one says theirs is! 

[Migalot]

Was this immediately after start?

It's showing an ambient outside temp of 9degrees and the coolant temp at 42 degrees!

If this was immediately upon starting, then your coolant temp sensor is goosed and will play hell with the fuelling (and hence lambdas!)

Yes. You can see by the RPM, it hadn't even settled down to 600RPM.

In that case, your coolant temp sensor is totally ficked!

Incorrect CTS readings will play hell with some of the other sensors - particularly lambda, and will affect the fuelling.

It's a known problem which needs to be fixed, and is highly likely to be linked.

It could very well be a £10 solution

Should I order the eurocarparts one then, James?

[Doctor Gollum]

your coolant temp sensor is goosed and will play hell with the fuelling (and hence lambdas!)

Like this one?

https://www.eurocarparts.com/p/starline-coolant-temperature-sensor-22488006s

Almost certainly not.

That's to say the guide applies to the 2.5/3.0.

You want this one.

https://www.ebay.co.uk/itm/283556554341

Are you sure mate? That's a square plug which I think was phased out on facelift models. Mig's Omega will have the later style oval connectors

100%

My '54 3.2 had the square plug. Which makes it really easy to confuse with the charcoal pcv plug.

[JamesV6CDX]

your coolant temp sensor is goosed and will play hell with the fuelling (and hence lambdas!)

Like this one?

https://www.eurocarparts.com/p/starline-coolant-temperature-sensor-22488006s

Almost certainly not.

That's to say the guide applies to the 2.5/3.0.

You want this one.

https://www.ebay.co.uk/itm/283556554341

Are you sure mate? That's a square plug which I think was phased out on facelift models. Mig's Omega will have the later style oval connectors

100%

My '54 3.2 had the square plug. Which makes it really easy to confuse with the charcoal pcv plug.

This is the one from my 2003 2.6 CDX. Definitely oval (the cars in bits so it was easy to check)

[Migalot]

This ebay one says for the 2.6 V6 and has an oval plug, as James said.

https://www.ebay.co.uk/itm/332398099110?chn=ps&norover=1&mkevt=1&mkrid=7101533165274578&mkcid=2&itemid=332398099110&targetid=4585169652812021&device=c&mktype=&googleloc=&poi=&campaignid=412354547&mkgroupid=1305120599331881&rlsatarget=pla-4585169652812021&abcId=9300541&merchantid=87779&msclkid=6192ddfbe0f4102ee1dfb9f498e56a0e

[Doctor Gollum]

I can only speak from my experience...

Also, the CTS is potentially a red herring as the only actual fault showing is an O2 heater fault.

Not to mention that the Grey wires from the the 02 sensors connect with the coolant temp sensor via the GreyBlack wires from both the camshaft position sensor and Air mass meter.

All seven components return to the ECU by way of BlueRed wire to X85/28

[JamesV6CDX]

You can have the one I've got here if you want it. It's a genuine GM one and will get you on the road quickly.

Happy to install it for you, it would be prudent to do the wiring tests at the same time.

I also have a theory that perhaps if the fuelling was wrong, maybe the 02 sensor heater was running constantly and has burnt itself out - I believe it's only meant to run for short periods when the car is in open loop

[Migalot]

You can have the one I've got here if you want it. It's a genuine GM one and will get you on the road quickly.

Happy to install it for you, it would be prudent to do the wiring tests at the same time.

I also have a theory that perhaps if the fuelling was wrong, maybe the 02 sensor heater was running constantly and has burnt itself out - I believe it's only meant to run for short periods when the car is in open loop

Thanks James, but I've just ordered the Eurocarparts one. As it's next door to the supermarket I'm going to tomorrow, I thought I may as well take the plunge!

Is it easy to replace or does it need an engine disassembly (like yours!  )?

[Migalot]

You can have the one I've got here if you want it. It's a genuine GM one and will get you on the road quickly.

Happy to install it for you, it would be prudent to do the wiring tests at the same time.

I also have a theory that perhaps if the fuelling was wrong, maybe the 02 sensor heater was running constantly and has burnt itself out - I believe it's only meant to run for short periods when the car is in open loop

Thanks James, but I've just ordered the Eurocarparts one. As it's next door to the supermarket I'm going to tomorrow, I thought I may as well take the plunge!

Is it easy to replace or does it need an engine disassembly (like yours!  )?

I just checked the OOF maintenance guide and I see it is a plenum-off job, so I think over to you!!

If you fancy this Thursday, the weather looks OK-ish and the teachers are on strike at the School, so parking should be fine!

[JamesV6CDX]

It's a plenum off job for sure which I'm sure you'd be ok with. I can't recall from memory if it's then accessible, or if the inlet manifold and injectors need to come out as well.

Just let me know if you need some help

[Migalot]

It's a plenum off job for sure which I'm sure you'd be ok with. I can't recall from memory if it's then accessible, or if the inlet manifold and injectors need to come out as well.

Just let me know if you need some help

See above!

More a case of can you do it for me, rather than helping me! 

And, yes, I will deffo pay you for travel and time. 

[Doctor Gollum]

I can only speak from my experience...

Also, the CTS is potentially a red herring as the only actual fault showing is an O2 heater fault.

Not to mention that the Grey wires from the the 02 sensors connect with the coolant temp sensor via the GreyBlack wires from both the camshaft position sensor and Air mass meter.

All seven components return to the ECU by way of BlueRed wire to X85/28

[JamesV6CDX]

I've an appointment on Thursday. Free tomorrow afternoon?  I can possibly make that work