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ZC501967 AC404789 ZC501968 MB991824 MB991827 MB991910 Data link connector AA00 To prevent damage to scan tool MB991958, always turn the 8. Connect scan tool MB991958 to the data link connector. 9. Use Actuator test 9 to drive the fuel pump. Check that there is 10. Stop the fuel pump. 11. Start the engine and run at idle. 12. Measure fuel pressure while the engine is running at idle. Standard value: Approximately 324 kPa (47 psi) at 13. Check to see that fuel pressure at idle does not drop even 14. If any of fuel pressure measured in steps 12 to 13 is out of SYMPTOM PROBABLE CAUSE REMEDY ⦆ Fuel pressure too low ⦆ Fuel pressure drops after revving Clogged fuel filter Replace fuel filter Fuel leaking to return side due to Replace fuel pressure regulator Low fuel pump delivery pressure Replace fuel pump Fuel pressure too high Binding valve in fuel pressure Replace fuel pressure regulator 15. Stop the engine and observe fuel pressure gauge reading. It (1) Squeeze the fuel supply line closed to confirm leak-down (2) If pressure continues to drop with both fuel lines squeezed SYMPTOM PROBABLE CAUSE REMEDY Fuel pressure drops gradually Leaky injector Replace injector Leaky fuel regulator valve seat Replace fuel pressure regulator Fuel pressure drops sharply Check valve in fuel pump is Replace fuel pump 16. Release residual pressure from the fuel pipe line. (Refer Cover the hose connection with shop towels to prevent MULTIPORT FUEL INJECTION (MFI) 13Aa-19 ON-VEHICLE SERVICE |