Help with Punto GT3

[chris_puntoGT]

Hello, i've just got another GT and its not runing the best its sounds abit ticky when drivng around but not on boost and its backfireing like a gooden a mean it sounds like a gun shot i put 30quids worth of petrol in it and got 65miles before a refil and a wernt hammering it everywhere so that cant be right, just had full service and mot, any ideas? can give more information and photos cheers

[GT Jamie]

sounds like afm mate

[Damosan]

As above or lambda sensor

[Superman]

More surprised someone passed it through an MOT if its actually returning less than 14mpg which is hard to believe in itself.

If its backfiring, why continue to drive it? You'll only cause long term damage to the engine, thats if its not fubared already!

What did the full service consist of? You should start with giving it a proper full service including spark plugs, check the gaps, maybe renew the HT leads and see where that gets you? Then move on to the next thing if the car is still the same.

The tapping is likely to be the tappets, whip the camshaft cover off and check the clearances under all of the cam lobes, you may find one or two are worn and the clearances are too broad, amking more noise and wearing the cam out even quicker.

[chris_puntoGT]

Cheers for info all helps. Did oil. filter's, plugs, new hoseing on FMIC, give it a gud clean its got a BMCA airbox on it that looks clean, just checked leads they looked fine but got Kv85s on order, gunna get new AFM. And not been driving it constant as i have another Gt and a 500twinair i been driving it to see if i can suss the problem i was putting the backfire down to the exhaust system at first so cant be that gunna try lambda sensor. So this cant be a fueling problem???

Gunna look into tappets is it easyer to change them or change the top half?

[jrracing]

Just make sure you get a genuine Bosch AFM as the pattern ones are carp.

[chris_puntoGT]

safety will do they abit heavy on pocket tho rnt they. http://www.micksgarage.com/engine-pa...gt-turbo/7762/ £586 hellfire the aftermarket are only 40quid

[sicskate]

A working second hand AFM will do the job

I'd recommend you try the one from your other gt first.

[Todd]

In answer to your question regarding if its a fuelling issue......

If the lamda or afm are reading incorrect mixture or amount of air being taken in, then the fuel will be all over the place.
I'd be inclined to check coil pack too.

[Superwhitevanman]

was it running ok before the service or was it back firing then too ?