Rough running at light throttle

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John Vine
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#10:

Thanks, James.

For us MBE folks, does an OBD scanner offer anything that Easimap doesn't? 

JV

aerobod
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Hi John, I don't think an OBD scanner will give anything from the MBE 9A4 or 992 ECUs that Easimap can't display.

James

Tom_Arundel
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Talk to Lewis Hamilton, he had the same problem in Mexico and said `The track was much higher up than we expected, we thought it was at sea level but it wasn`t and it made the motor misfire`.. *silly*.....Sorry!

Is yours a variable or fixed cam engine?

Is the air filter clean?

Any manifold air leaks ?

cold and wet needs more fuel so if it`s lean to start with it will get leaner.....chug...chug!

3500 is where it starts to `get on the cam` 

 

 

John Vine
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Thanks, James.

JV

DW199
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The car went back to Caterham Gatwick under warranty last week.  Apparently the problem is due to the catalytic converter breaking up.  The car has only done 3.5k miles so I am slightly surprised.  It will be interesting to see how it runs after the cat is replaced.  

aerobod
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Usually a cat break-up is due to running too rich of a mixture for too long. I would ensure that the cause of the break-up is identified, as it is very uncommon at such a low mileage unless the converter has suffered a very significant mechanical shock.

James

John Vine
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I agree with James. 

Did CC offer any comment or explanation about what may have caused the cat damage?  Cats aren't cheap, so I'd hope that they didn't simply replace it without a lot of investigation.  For example, did they say anything about the lambda sensor?

Do you happen to know whether the cat was fitted continuously throughout the car's Academy life, and does the 3.5K miles include all the track usage?  Indeed, was the cat the same age as the car, I wonder?  I'm even wondering whether the lambda sensor has been faulty throughout your ownership, leading to continuous over-fuelling.

JV

DW199
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You are right, cats aren't cheap looking at the price on the Caterham parts site.  I'm glad they have agreed to cover this under warranty.  The car did the Academy followed by a few track days so I think the mileage is about right.  I don't know whether the cat is the original.  I will ask CC the relevant questions when they confirm the availability or otherwise of a replacement.

DW199
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CC have no cats or decat pipes in stock and don't know when they will receive any. Apparently it is not totally unheard of for a cat to fail in a race/ex-race car due to 'hard use'.  They will look for any underlying cause when the car has a properly functioning exhaust system. 

All a bit frustrating.