Help diagnose engine management light fault please.

[thexav]

Hi a mate of mine is having problems with the engine management light being always on in his Mazda 6, also being hessitant on setting off. The car has a sports cat and cone air filter.

I would like to know if the sports open filter can damage the air flow meter

Where should he check first to get to the bottom of this fault? What are the likely culprits going to be?

 

[T9 man]

Hi a mate of mine is having problems with the engine management light being always on in his Mazda 6, also being hessitant on setting off. The car has a sports cat and cone air filter.

I would like to know if the sports open filter can damage the air flow meter

Where should he check first to get to the bottom of this fault? What are the likely culprits going to be?

Well not sure if a past similar fault is related but - I had the same thing when I had a sports CAT and a cone filter fitted. There were two different problems here: 1, The cone filter had no heat shield to protect it and was sucking in lots and lots of warm air. 2, The air coming in via the cone filter and not the OEM filter box was at a different rate to what the ECU was expecting and therefore did not match up to the link in program between the air coming in and the o2 sensor readings on the sports CAT.
The car went in for a remap and the man diagnosed this issue straight away, he done something to the map and the light was later extinguished and the throttle hesitancy went with it.

It may be nothing at all to do with your friends problem, but I thought I would pass on my own experience. Good luck with finding the fault

 

[MSJ]

what is the trouble code that is setting the light? are there any "pending codes"?

might be a good place to start........

 

[PedroS]

are you anywere near swindon ? i have a diagnostic tool....

 

[Charliep]

When fitting a sports cat sometimes the fitters connect the post lamdba sensor before the cat (because of the longer wires) and leave the pre lambda sensor out, which might work for a short while before the management light comes on. Or second lambda is not fitted to pipe for the same reason. in this case the lambda needs to be sleeved.

Obviously there are many more reasons that could be the cause, which is why it was recommended by pedroS to go on a diagnostic port and read the fault codes.

 

[stamford]

Could be that the ecu is not able to learn the changes made and is therefore confused with the readings due to the changes made. Open cone? Doesn't always help, best to make it enclosed or remote away from the engine heat. May also require a remap to tweak the fuelling and afr. Check with Mazda forums for likely causes as it may be common.

 

[jc denton]

My brother has a 323 sport with what sounds like the same problem, in his case its one of the coil packs!