The fuel cut I'm talking about is the overpressure fuelcut. The ECU monitors the intake manifold pressure using a MAP sensor (manifold absolute pressure). The manifold pressure is directly related to the boost pressure (obviously). When the MAP sees a pressure above the factory set point (~15psi on a 5-speed, it's lower for the auto), the ECU temporarily cuts the fuel to the engine until the manifold pressure drops below the set point. This prevents damage to the engine caused by overpressure. The feeling is a sudden jerking that will repeat until you let off the gas. It is relatively harmless, but uncomfortable. Hitting fuel cut is the indication that you have turned the boost pressure up too high, and you need to turn it back a bit.

Many here use this procedure of turning the boost up to fuel cut then backing off a little because it does not require an accurate boost gauge. You actually don't even need a boost gauge at all.

You'll need to tune the Dawes unit under actual driving conditions. You look kind of stupid driving down the road a few hundred feet, stopping, getting out, opening the hood, messing with the controller for a second, getting back in, driving another few hundred feet, stopping, etc...but this is the only way to do it. It will probably take 20-30 minutes to get the controller set perfectly.

• Anyone got directions on installing a Dawes MBC on a base'01 9-3?, JH, Wed, 1 Aug 2001 16:15:33
  • Re: Anyone got directions on installing a Dawes MBC on a base'01 9-3?, LDH, Wed, 1 Aug 2001 17:30:44
    • Thanks a lot but I've got a few more questions..., JH, Wed, 1 Aug 2001 18:08:51
      • A few more answers..., LDH, Wed, 1 Aug 2001 21:17:26
        • About fuel cut off..., JH, Wed, 1 Aug 2001 21:32:40
          • Clarification..., LDH, Wed, 1 Aug 2001 23:29:12 <-- Viewing This Message
            • WOT is achieved only when the pedal is fully to the floor, right?, JH, Thu, 2 Aug 2001 00:06:08
              • Yes...Wide Open Throttle WOT and, Dave, Fri, 3 Aug 2001 13:50:20
                • Re: Yes...Wide Open Throttle WOT and, herky, Sat, 16 Feb 2002 00:08:54
            • So basically..., JH, Wed, 1 Aug 2001 23:58:42
              • Yes..., LDH, Thu, 2 Aug 2001 01:20:49
                • Alright cool, thanks. I'm sure I'll know the jerking feeling..., JH, Thu, 2 Aug 2001 02:04:00
                  • Any Luck?, mwf, Thu, 2 Aug 2001 12:00:11
                    • Well, I just ordered the MBC so I'll definitely give a review..., JH, Thu, 2 Aug 2001 19:05:11

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