Haven't posted here for ages... but anyway, feelin' down at going back to work, get five miles from home and the car cuts-out in traffic. The bloody thing won't idle - and when it does, it's at 2,000 rpm.

I limp to my local dealer and I get a call several hours later to say they can't find anything amiss, but have reset the ECU and it now appears to be OK following a road-test.

When I pick-up the car, they ask if I use Shell Optimax - which I do predominantly - and I'm advised this petrol is causing problems with a few Honda's - "gummed-up sensors" in the exhaust.

Has anyone else experience of and/or heard of this?

Unsurprisingly, get the car warmed-up and a few miles later it starts cutting-out again.
Assuming I can get to the town where I work, I will try another dealer...

More anon.

 

Have you given the MAP sensor a tap?

I find it difficult to believe Optimax is responsible TBH. This sounds like typical dealer

 

Can't comment on your specific problem, but can agree with Neil.

You might ask your dealer if the few thousand other S2000's in the UK running exclusively on Optimax are also "gumming up"

 

Perhaps you could get the Dealer's comments in writing so that Shell UK are able to respond

 

it would point towards the lamda sensor though, (cutting out when hot) once the system goes into closed loop, if the o2 sensor is screwed you've had it.

 

What does that mean in accountant's/layman's terms Andy?

 

He almost sounds like he knows what he's talking about

I'd try the MAP sensor first.

 

sorry bout the delay, just got power back from a 3 hour power cut, if you can believe such a thing.

If it was the Map sensor I would expect it to misbehave at all times not just when the car heats up.

When the car is in open loop (i.e. cold) the engine works out the mix based on the coolant temperature and the readings from the map sensor.
it compares them against a table in the ecu and then has a stab at what the mix should be.
It isn't till the 02 sensor heats up that it can give accurate readings, once that happens the car goes into closed loop which means it uses the map readings the ECT and compares them against the readings it gets from the 02 Sensor.

It then adjust the mix based on that information.

what it sounds like is happening here is that it is all ok until the 02 sensor comes in and starts feeding the ECU guff information, causing it to feed far too rich a mix into the system.

tis one theory anyway.
Still hitting the map sensor with a hammer is cheap and satisfying.

 

I'd go along with C7BLE cos I had the lambda (O2) sensor go on my calibra and it would stall all the time and really misbehave.. but only once it had warmed up..

when cold it was pretty much fine on the super-rich mixture it uses then (like you're old 'choke'..

they're not cheap, about

 

depending on how the sensor is exposed it may just be possible to take it off and spray it with some carb cleaner, if it is gunged up, but it depends if that is the problem or the sensor is just faulty.