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Engine backfire during overrun

Ross Hubbard

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Just trying to tune my Link G1 V5, on my 4age with ITBs so that it doesn't backfire. It usually occurs when getting back on the throttle after de-accelerating (one big bang).  I have followed the directions in the tuning manual by looking at the idle vacuum signal and setting the overrun a few kpa under that figure but havent managed to get rid of it yet (possibly due to dodgy MAP signal with ITBs).  AF ratios during overrun flucuate from 14-18.  

The car is used mostly for motorsport and I figure having some fuel entering the cylinders on the overrun is probably good as it would aid piston cooling?  Would one solution be to increase the fuel throughout the rev range at 0 TPS thereby encouraging more complete fuel burn inside the combustion chamber at 0 throttle?   Just a theory....but Im thinking this could also help with throttle response when getting back on the throttle.

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In the ECU configuration you will have the option of having over run fuel cut turned on or off.

If you wish to keep fuel going through the engine set this setting to off.

Then is you increase the numbers in the overrun area of the map you will get more fuel through.

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