Hi all,

After a recent brush with bore wash, and after that removing the valve covers to check my secondary tensioners (all good) I started the car up again and it ran well whilst warming up, then I got a reduced performance warning with an amber light. checked for codes and came up with P1647 which seems to point to the upstream O2 sensor on bank B. having checked the forum for similar fault, no one seems to report the reduced performance warning. can anyone tell me if this is normal? or am I barking up the wrong tree (or maybe just barking?)

any help gratefully recieved

 

I've ordered a new O2 sensor, going on advice elsewhere on here by Red October I have plumped for one from an X-Type. As the car clears the fault by itself when cold and only faults as it reaches normal running temp I cant forsee any big issues, other than the fun involved in changing the sensor itself. I will post here on my experiences once done.

 

Greetings - why do I think this rings a bell... Well I did have my share of the bore wash experience. I am assuming you resolved that by a little bit of oil in each cylinder. The exhaust was probably blue-ish and smelled like a fresh spring day (lol). I think (and I say I think - this was 2 years ago) I also got the 1647. It kind of made sense to me back then as thinking the oil in the exhaust may have ticked off the sensors. But I never replaced my sensors so for the love of me I can't recall if it eventually just disappeared after 'driving it off' or if I actually had another code that I eventually cleared off. Sorry, probably not much of a help, but thought I would share.

 

I'd be worried it might be the wrong sensor but so long as it isn't then it should be fine.

 

@ Blue, thanks for sharing... always good to know that an experience is not suffered alone. Yep oil in the pots and lots of smoke... I'm driving the car on friday and saturday so will see what happens.

@ Jag V8 My other life when not tinkering with my Jag is in engineering working with PLC and data bus systems, Same principal as the ECU and sensors on a car, so as long as the sensor works in the same way, which this one is meant to it will work ok. at worst it will throw up a fault code by being incompatible. thanks too for your input. always good to hear the advice and thoughts of others.

 

My worry is that its voltage & current behaviour with O2 might be different, which would mislead the PCM and it would then get fuelling wrong. That then means lean or rich running - both bad.

Like a resistor - doesn't matter who makes the 1K one but matters if one fits a 10K one where 1K is needed.

 

That would make a difference for sure, I intend to compare the spec of the sensor should I need to fit one. However, with one more nod to Blue_XJ8 I took my car for a run tonight and for some reason known only to the gods of gasoline the light did not come back on, so I am going to assume that the oil has burned off now and all is well.

Thanks again for your input.

Have a good weekend.