strange power problem with 348

[adi]

My 348 seems a bit unhappy when cold at the moment - sometimes there is practically no power ie minimum revs even when pressing the throttle. As the car warms up, the power starts to come in jerks, then things are fine when I have temp. I have noticed more coking on the rh bank exhausts than the left (challenge system fitted). I'm guessing some of the cylinders aren't firing properly?

Advice much appreciated, before I have to acknowledge it needs a trip to the dealers...

>>> Edited by adi on Monday 9th September 14:07

[craigw]

try emailing qv autos/calling them, they are always happy to give advice. [e-mail]
01344 622 011 Ask for Mike/Phil

Alternatively Joe Macari have a good guy there called Aldo.

[domster]

quote:My 348 seems a bit unhappy when cold at the moment - sometimes there is practically no power ie minimum revs even when pressing the throttle. As the car warms up, the power starts to come in jerks, then things are fine when I have temp. I have noticed more coking on the rh bank exhausts than the left (challenge system fitted). I'm guessing some of the cylinders aren't firing properly?

Advice much appreciated, before I have to acknowledge it needs a trip to the dealers...

>>> Edited by adi on Monday 9th September 14:07

Sounds like overfuelling to me, probably sorts itself out when the lambdas kick in after about five minutes and start adjusting the misture back to what it should be. At a guess, it will need some fiddling with sensors (water temp sensor may be telling the engine it is cold all the time for example) and the engine management side of things. Not serious, but a few hours' labour. Better call the experts as I'm not one

[adi]

Thanks for the replies chaps - I think a trip to the shop is defo a good move (I avoid it because I always get tempted by new toys which I can't afford every time I go!)

[adi]

I hear that plug fouling can be a problem - particularly if the car has been used for short runs and in heavy rain?? Anyone experienced this and did the symptoms relate to the problem I'm having? Just a thought...

[domster]

Plugs could be something to do with it, but it could be many things i.e. you mention one exhaust being more fouled than the other - if they split the engine into two banks of four for exhaust purposes, they probably have a separate lambda sensor and cat for each side. If one lambda is playing up or one cat is blocked etc then that may cause the problem.

A dealer needs to take a look, but from your symptoms, I'd say it had an over-fuelling and/or ignition problem when during the 'cold' running cycle.

My Lotus Carlton used to suffer from so many misfires, I used to spend ages researching the causes. There are something like 96 possible causes in a modern engine with all its sensors and engine management. The one bonus is engine diagnostics - they'll plug something in and check injector pulse duration, lambda switching, the works. Don't even bother guessing until a garage has had a peek