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Discussion Starter #1
Hi Guys,

I am new here and hope I can get some solutions for my problem.

I have a 2008 Mini One 1.4 with about 100.000km on the clock.

Some day the yellow engine light appeard and the Lambda / Oxygen sensor was replaced (Bosch sensor) after a few 1000km same error again.

At the Mini Dealership they had the following error codes 2A8B, 2ACB, 2F1A
So they checked the cables from the engine control to the lambda sensor all ok.
Oxygen sensor was replaced again, this time original sensor.

After a few 1000km same error again, so they changed the thermostat and again a new sensor.

So long so good, now after 12.000km same error 2A8B, I can not imagine that the sensor is damaged again?!

Any suggestion?

Best regards from Germany

Sebastian
 

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Hi, you have to find out what is burning it out and the likely cause is retarded timing due to a worn/stretched timing chain. If it has not been changed it is well overdue. If it has been changed then it needs doing again at 100K. Mike1967 explains this in many threads. That's all I have for you...
 

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as scudder points out timing chain and valve stem seals thats a head off job unless have a special tool and patience of a vicker to do in place ie picking the valve spring off , also rocker cover pcv valve while at then replace the sensors and cat and might be ok.. this all said on a 100k car might not be worth the hassle,, if you have just bought it then reject it take it back to dealer,, if bought private then you will struggle to get money back.
 

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Discussion Starter #4
as scudder points out timing chain and valve stem seals thats a head off job unless have a special tool and patience of a vicker to do in place ie picking the valve spring off , also rocker cover pcv valve while at then replace the sensors and cat and might be ok.. this all said on a 100k car might not be worth the hassle,, if you have just bought it then reject it take it back to dealer,, if bought private then you will struggle to get money back.
Hi, you have to find out what is burning it out and the likely cause is retarded timing due to a worn/stretched timing chain. If it has not been changed it is well overdue. If it has been changed then it needs doing again at 100K. Mike1967 explains this in many threads. That's all I have for you...
Ok thank you both, thing is the last sensor lasted for about 12.000km and now sadly the problem is back.
The last repairs were paid, but now the guarantee is over. If I am lucky the last sensor will be replaced for free.

I have thought about replacing the chain adjuster, there was a newer longer one available maybe this will solve the problem too.
 

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Oh! replacing the tensioner is not a solution to chain wear. If it is worn all you will do is take up the slack with the risk of jumping timing or breaking a top guide which will wreck your engine. Up to you though. If it was me I would do more research on timing failures and interference engines. You might find it hard to sleep after reading the stories :)
 

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Oh! replacing the tensioner is not a solution to chain wear. If it is worn all you will do is take up the slack with the risk of jumping timing or breaking a top guide which will wreck your engine. Up to you though. If it was me I would do more research on timing failures and interference engines. You might find it hard to sleep after reading the stories :)
totally agree with your comments
 

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Discussion Starter #7
But are there any sings to detect a worn/stretched timing chain?
I mean the car runs smoothly, it makes his top speed, doesn't take more fuel or so and strangely the last sensor lasted 12.000km :unsure:
 

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Firstly, a lambda sensor (decent make) should last up to 100k miles. Yes, you can get a dummy tensioner and measure the stretch on the chain. Find an online guide for doing this, over 68mm from the neck of the tensioner to the tip and the chain is trashed.
 

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I had same issue - on my daughters car mini one - had burned out exhaust valve causing too much fuel to enter exhaust system - so causing Oxygen sensor to become contaminated and fail - was going through new sensor every 3-6 months , may be worth doing a compression test - just to check valves
 

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Discussion Starter #11
I had same issue - on my daughters car mini one - had burned out exhaust valve causing too much fuel to enter exhaust system - so causing Oxygen sensor to become contaminated and fail - was going through new sensor every 3-6 months , may be worth doing a compression test - just to check valves
And how did you find out? And most important, how did you fix it?:unsure:
 

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And how did you find out? And most important, how did you fix it?:unsure:
found out after using a compression test on engine - after second bosh lamba sensor had gone within 6 months - compression test will show any valve leakage - had to remove head and replaced valve - re lapped in all valves - and replaced oil stem seals
 

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found out after using a compression test on engine - after second bosh lamba sensor had gone within 6 months - compression test will show any valve leakage - had to remove head and replaced valve - re lapped in all valves - and replaced oil stem seals
it dont take much to effect them, i just fell in to a pit of pain with cooper s n14 i rebuilt piston and rings and thought i would be a clever bugger and use the latest piston rings sets from n18 and b series and also they do list fit the n14 engines, they have a single coated oil control ring thats more coated plastic so had really good compression but on over run would smoke when hot, and after a lot of trying stuff form rocker cover and catch cans and turbo cartridge etc,, still fixed nothing,, ironically when can was on road no smoke on throttle totally clear but whispy smoke on idle when cold and smell of oil when hot,, then we stuck it on rolling road while reading crankcase pressure,, ie idle -3psi when rev'd 3-6k would force oil out the crankcase and collect in the inlet... so once again head off and pistons out and use hepolte rings me thinks, live and learn but a expensive lesson
 

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Discussion Starter #14
hey guys, I will change the timing chain with all necessary parts (oil change etc.)

Would you recommend to change the spark plugs as well after this is all done?
(They have been changed like 20.000km ago)
 

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hey guys, I will change the timing chain with all necessary parts (oil change etc.)

Would you recommend to change the spark plugs as well after this is all done?
(They have been changed like 20.000km ago)
plugs should be ok with those km,
 

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Ok, perfect.
So a worn/stretched timing chain shouldn't effect or damage the spark plugs?
no worn stretch timing chain if driven for to long will hurt 02 sensors and cat and can effect valve stem seals and valves ie have see many cracked before, i also been seeing a fair few valve seats dropping out on to rear of the valves if overheated
 

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Discussion Starter #18
no worn stretch timing chain if driven for to long will hurt 02 sensors and cat and can effect valve stem seals and valves ie have see many cracked before, i also been seeing a fair few valve seats dropping out on to rear of the valves if overheated
so, the timing chain was changed yesterday, it was stretched as you suspected.

The engine runs smoothly but I noticed a strange noise after the change:


Is this normal?
 

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cant tell form a recording sorry it dont work that well over the laptop, if on doubt you should take back to where doe the chain kit,
 

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Discussion Starter #20
cant tell form a recording sorry it dont work that well over the laptop, if on doubt you should take back to where doe the chain kit,
Yes you are right, its a little hard to hear, I have talked to the shop, sadly its an one hour drive be he will look after it.
I uploaded another sound/video maybe you could have a listen here :) should be better to hear

 
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