Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1989 Mercedes Benz 300CEFACTORY OEM SERVICE PROCEDURE
Fuel Distributor Delivery Volume
- Unplug oxygen sensor lead under right front floor mat. At fuel distributor, disconnect small fuel return line connected between fuel distributor and diaphragm pressure regulator. Plug line. Connect hose to open fuel distributor port.
- Place opposite end of hose in measuring glass or beaker. Remove fuel pump relay. Bridge sockets No. 7 and 8 with jumper wire to run fuel pump for one minute. Verify fuel delivery volume of 4.4-5.0 ozs. (.13-.15L) per minute with 11.5 volts to fuel pump. If delivery volume is low, replace fuel distributor or differential pressure regulator as required.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.