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Have you tried swapping the O2 sensors around?
see if the fault follows the sensor

Such is the downside of linear threads- that was the first thing tried.

Also injectors swapped, different ECU, plugs, coils and leads. Compression tested.

Lower intake manifold gaskets changed... this fixed mostly a mis-fire it was experiencing.

Hence looking at likely reasons for a cylinder to run rich outside of the electronics.

I'll have a look at disabling BLMs for a exhaust temp test... the O2 sensor voltages seem healthier when not in closed loop. Like startup.
Found the entry: BLM - If coolant <= this, skip learning. (Currently 39.5*)

Just need to pull the memcal and reflash it, I modified it to an AMD 29F010 flash ROM- no UV light required....

Worth a bash.

I had the lazy O2 issue on our old VS. What I did was to re-wire the O2 sensor earths directly to the engine block, fitted new O2 sensors and things much improved but one was always slightly more lazy than the other but if memory serves me correctly bank to bank variation was only a couple of % rather than 20%.

I still wonder about the wiring, as it is wired and if the drawing is accurate even though you have disabled the heaters at the power source it would still be possible to get a stray current into the sensor signal wire because it is still connected to earth.

I have another VS wiring diagram that I downloaded from Dr Bobs old website which shows the exact same wiring configuration

Well there was an interesting afternoon.

The missus took the VK for a shopping trip to Geelong.

Get a phone call at 2pm... " Honey I blew up the the car, I overtook a truck and then it made some strange sounds and smoke came out of the bonnet"

WTF?, Um Shit... "Okay I'll jump in the Statesman and come to the rescue"... (Lucky I changed the diff centre last week.. LSD was rooted)

I asked her half way on my trip (once phone reception was back) if she was prepared to open the bonnet and take a few photos so I could MAYBE arm myself with anything I could buy on my way through Colac to repair the damage (Wishful thinking).

Nothing, a few drops of coolant in odd places- but no broken belts or anything obvious. Oh well, just have to get there and find out.

An hour later I find the stranded missus having a nap and the kids watching a dvd on the screens.

Now its late and I haven't taken any pictures yet myself.

What I found is bewildering. Firstly I saw some very strange pink colouring on the water pump housing. (I will take a pic I promise)
Then I wiggled the water pump pulley... lots of movement. Okay.. that is our problem. Could explain the coolant mess. I opened the radiator cap and clearly it was low.

Bearing likely is screwed. Just happens I have a spare near new pump from the VP engine I fitted 2 yrs ago.... and they fit ecotecs. Bonus.

BUT! For some reason I randomly decided to pour in some more water I had in the boot to see how much it had lost. 1 litre later it start leaking onto the road!

From the radiator! Now double WTF?!! It has a fucking massive 3" split in one of the alloy tanks! Now fair enough its a Chinese ebay special.. only 13months old.

And I noticed the engine isn't idling smoothly either while driving it on and off the car trailer I had to rent for 4 hours to get the thing home. (Only $80 after deposit refund)

Tomorrow, weather permitting, I'll dig deeper and find the rest of the problem.

The big question is... what broke first, and did the water pump bearing get so hot as to make smoke... missus swears it wasn't steam... it stank.... Did it blow a head gasket, pressurize the system and blow everything else. I don't think it overheated.

She reckons when it happened she looked at the gauges, and nothing was pointing 'to the red'. So who knows.

(She also thinks it Karma because it was a Circus truck and she doesn't like clowns... )

Much fun.

Edit.. I hate minor typos.

That's no good man, certainly sounds like head gasket or similar to pressurize the coolant system enough to pop the tank!!

Would explain it not running too well also!

Hopefully its not a big issue but at least you can blame the missus

Even if it where a blown head gasket, the cap SHOULD have vented the extra high pressure in the cooling system...

The failing/leaking water pump letting the coolant out will be why the guage didn't read, those coolant temp senders don't read steam very well...

I bet it has a blown gasket/cracked head and pressurised the cooling system to breaking point, those china radiators come with a smaller cap than the stock type, my experience with them is they are of poor quaility, I run china radiators in the race car, I have found caps from new that don't have enough spring pressure to seal at all, and also had the other extreme where as the spring is that hard it won't break off at all.

Bummer about the breakdown. sounds like work ahead

Bugger

I've lost a load of coolant and the dash temp gauge never really moved from it's normal running temp/position....

Half time coffee break.

Yup... Compression test revealed almost nothing on #3 cylinder.

Tested 1,3 and 5... then the needle fell off the gauge while testing #2. Bugger. We know the answer anyway.

All cylinders were ~170 psi just couple weeks ago. So I only did LIM gaskets.

Slowly its coming apart.. lots of things to remove before I can get the heads off.

that sucks man!

that's an odd spot for the tank to split too!

not sure if its anything similar, I had an alloy tank in my torana a while back, ended up getting a few leaks in it and turned out to be stray current, totally stuffed the radiator, heaps of pin holes in it, maybe similar for yours.

hard to know though, could just be the comp in the radiator was enough to blow the weakest point.

Someone might be able to weld that up rather than having to replace it.