Pinking under load...

[funkyelise]

Hi all. New to the site, but wondering if anyone out there's had the same prob. Got an Elise Mk1 which has started to pink under load. Nothin major, but its there. Seems to have started after fitting a K&N filter kit. Anyone experienced this and poss. fix?

[cuzza]

Sounds like a dodgy lambda sensor - this passes info to the ecu about emissions (I think) so it can make corrections to the mixture etc. As you've fitted the K&N this will alter the amount of air getting in a mean the car is running a bit lean. So if the lambda is knackered then the ecu won't know to change the mixture.

Now lets see how long it takes for an expert to correct me.....

[funkyelise]

Thanks cuzza. Tried running it on super unleaded and seems better now. I'm hoping it just needs a new set of plugs...B service imminent!

[domster]

cuzza said:

Sounds like a dodgy lambda sensor - this passes info to the ecu about emissions (I think) so it can make corrections to the mixture etc. As you've fitted the K&N this will alter the amount of air getting in a mean the car is running a bit lean. So if the lambda is knackered then the ecu won't know to change the mixture. Now lets see how long it takes for an expert to correct me.....

I doubt it is the lambda. When lambdas go they usualy pack up completely and the engine then deafults to a rich running mode. It is true that the lambda can fluctuate, but it normally does so at idle causing 'hunting'. When the engine is under load I believe that the lambdas are not used by the engine management (I may be wrong myself, tho').

It is more likely to be plugs/leads or any one of the 40 or so fuelling/ignition problems that could cause this.

PS A lambda fault will show on doagnostic softwars, so your dealer should be able to prove or disprove the theory very quickly.

[annodomini2]

check the air flow meter, could be thinking its running less air and weakening the mixture.

[funkyelise]

Seems to be sorted. Following a B service (inc. new plugs), a full tank of Optimax and a 400 mile round trip, the pinking seems to have disappeared (he says hopefully not tempting fate!) Also had wheel alignment done...what a difference a properly set-up car makes! Cheers for the advise though

[fergusd]

Running on optimax may be masking any problem, try a few tanks of 95 before you conclude it's sorted . . .

There is no air flow meter on the Elise K series.

The lambda probe IS used under cruise conditions, probably not, though, under full throttle.

An air filter is almost definately not going to change the mixture sufficiently to cause pinking.

No answers as to why it's pinking . . .

Check the plugs . . .

Fd