On 7/18/07, Tom Hargrave <[EMAIL PROTECTED]> wrote: > > There is a control pressure actuator attached to the side of the fuel > distributor. A steel reed inside oscillates up and down, controlled by the > computer. Feedback from the oxygen sensor modifies the reed duty cycle. > The > duty cycle of the oscillation determines the control pressure to the > bottom > of the fuel distributor because the duty cycle changes the amount of fuel > that's allowed to pass through. The control pressure determines the fuel > mixture. If this reed fails, as it did in one of my 300E's (twice, both > times cracked), strange things happen because the system is no longer > stable. It can stick open, stick closed or just not oscillate. > > If your fuel pressure is correct then I'd suspect this part.
I'll talk to my mechanic about checking the fuel pressure. Is there any way to determine the condition of the reed? And Mitch is correct, the system does flow a lot of fuel. They do this for 2 > reasons. The first reason is that they actually use hydraulic pressure > generated by the fuel flow, plus restriction (a pressure regulator), to > control the system (mentioned above) and to do this, they have much more > fuel flowing through the system than needed to maintain a steady control > pressure. The second reason is to keep the fuel cool. The car would not be > running if you had a blockage in the tank, etc... > > Some have one fuel pump, some have 2. Both of my 1986 300E's had one. > > Earlier CIS systems did not a control pressure regulator. They depended > entirely on the balance between the air flow sensor plate and a calibrated > internal spring to manage fuel flow. > > Thanks, > Tom Hargrave > www.kegkits.com > 256-656-1924 > > > _______________________________________ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
