Backfiring on petrol

[sergeara]

Hi everybody, my GQ 95 patrol starts and runs perfectly on LPG but as I run on ptrol it does not go and starts backfiring !!! I cleand injectors, Changed spark plugs and leads + button, . . . still same!!!
any help ?

[XLR8]

Check the MAF sensor. it may be damaged or just dirty.

[YNOT]

Backfiring is usually caused by one of two things, lean out, or poor ignition.
In your case you've replaced most of the ignition system already, so ignition seems unlikely. That leaves lean mixtures as the most likely cause.
Check for split or leaking intake ducting, leaking inlet manifold gaskets etc. Any air leak after the airflow meter will mean air is getting into the cylinders that has not been measured by the mass air flow sensor, and will cause lean mixtures.
I suspect the fault will be in the intake ducting before the gas mixer, if it was leaking after the mixer it would be backfiring on gas as well.

Tony

[Matmobile]

is the fuel fresh or stale?

[v.t.c 4800]

the problem in in ignition system

[black-mav]

put a hplly opn mine from recarb and runs like a dream

[skidy04]

Hi might be a silly question but what it a "hplly opn "??