engine help please!

Discussion in 'General Motoring' started by Carjunky via CarKB.com, May 14, 2007.

  1. Ok.

    In my sl2, I have a fresh rebuild, maybe 3000 miles. Using my WBo2 guage the
    car wants to go lean at idle and at cruising throttle. Enough that the car
    stumbles when the engine is all warmed up. When you hit the gas at idle speed
    the car hesitates before it takes off. Looking at my vacuum gauge, the needle
    reads about 21-22 psi vacuum and fluctuated rapidly about 2 psi up and down.
    What do you guys think the problem could be?

    New -plugs/wires, map sensor, re manufactured head
    fuel pressure regulator is set at 44psi
    EGR valve is removed and using a block off plate
     
    Carjunky via CarKB.com, May 14, 2007
    #1
  2. Carjunky via CarKB.com

    Gyzmologist Guest

    Removing the EGR was a mistake. If you are going to modify the engine,
    you must also modify the ECU's programming. Exhaust gas is inert, adding
    it to the intake charge does not affect the mixture. However, the
    addition of exhaust gas will cause the ECU to see an increase in
    manifold pressure and normally will inject more fuel if its fuel map
    were not programmed for EGR. This is primarily a combination of manifold
    pressure & throttle position, though engine RPM and temperature are also
    involved. By eliminating the EGR you are now getting more air for the
    same manifold pressure than the ECU's fuel mapped is programmed for.
    Either reinstall the EGR or get the ECU reprogrammed.

    HTH
    Gyz
     
    Gyzmologist, Jun 5, 2007
    #2
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