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Discussion Starter · #1 ·
I have read alot about fuel cut,but exactly what is it?
We all have had turbo lag ,and virtually made it non existant.
But fuel cut! does this mean the car stalls at high revs.I usually get this at 7500rpm on the red line .
Is it a delay more that turbo lag before fuel is pumped to the right places?
Depending on weather conditions ,my boost fluctuates,and occasionally I experience what I would describe as a lag.
The point to which pick up again is achieved.

cheers paul s

Discussion Starter · #2 ·
Fuel cut is Mitsi's way of controlling the engine. Where most manufacturers cut ignition to stop over reving mitsi cut the fuel supply and thus limit the revs. Fuel cut can also occur if the boost pressure is increased. This is because unlike most turbo cars the EVO' ECU measures boost pressure by how much air is entering the engine, not by actual boost pressure. If the ECU thinks that too much air is entering for a given RPM/load, and thus the boost pressure is too high, it cuts the fuel momentarily to allow the boost pressure to reduce. A lot of turbo cars have an overboost switch, which is basically a pressure switch in one of the boost noses, and when the boost pressure is too great it will cut the ignition.

Fuel cuts aren't very nice as the car lurches and it puts a lot of strain on the engine. I've heard mention of con rods being bent, but not actually spoken to anyone who has done it.

This is by no means a comprehensive answer and is only my take on things after a bit of research. I'm sure someone else will provide a more in depth answer.


Discussion Starter · #3 ·
How do you know if this is happening,what's the symtoms.?
Does the engine grind to a halt all of a sudden?
I sometimes experience a delay in pick up,but put this down to alittle lag.


paul s

Discussion Starter · #4 ·
I suffered from overboost problems due to a rotted wastegate actuator diaphragm. The ECU senses the overboost and cuts the fuel in a most alarming fashion with a nice big backfire trype noise from within the engine internals and your head almost breaks off your neck. It is certainly a different animal from the over rev limiter/cutoff which is a kitten in comparison!

Discussion Starter · #5 ·

if it ever happens, you'll know. It is very brutal; a big noise, as if the engine was stopped rotating by a solid element. It actually makes you want to stop and check if your gearbox or some other device is not lying on the road behind you...
As it usually happens during hard acceleration, it is also true about the neck thing

Hope you don't experience it though

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