2000 Hyundai Sonata



June, 14, 2010 AT 7:02 AM

Engine Performance problem
2000 Hyundai Sonata 4 cyl Two Wheel Drive Automatic 155000 miles

Can you please tell me where the fuel line pressure valve is on a 2000 Hyundai Sonata? I looked up by the fuel rails and all over under the hood and can not find any valve on the fuel lines. My code checker says the fuel mixture is too lean, so I'd like to see what pressure the fuel pump is putting out, especially since its probably a fuel pump with 155000 miles on it.

Also, the car runs awful when its cold and once while I've had it, it cycled approximately 1,000 rpms (~1200 rpm to 2200 to 1200 then 2200 and so on) on its own, as many as 15 or 20 times when it was warming up, and then it stopped on its own. I never touched the gas pedal. It idles very rough but has plenty of power when warmed up for 15 minutes (which seems like a long time to wait for it to run decent). Are there any notorious Sonata or Hyundai problems I should be aware of that might help me fix this car? Thanks again,

Any suggestions


1 Answer



June, 14, 2010 AT 7:50 AM

Hi kegelmta, Welcome to 2carpros and TY for the donation


Reduce the internal pressure of the fuel pipes and hoses by the following procedures.
Open the trunk door and disconnect the fuel pump harness connector in the trunk room.
Start the engine and after it stalls, turn the ignition switch to the OFF position.
Disconnect the battery negative (-) terminal.
Connect the fuel pump harness connector.
Remove the bolt connecting the fuel line to the fuel delivery pipe. CAUTION: Cover the hose connecting with a shop towel to prevent splashing of fuel caused by fuel residual pressure in the fuel line.
Install the special service tool (SST) for measuring the fuel pressure.
Disconnect the fuel feed from the delivery pipe. CAUTION: Cover the hose connection with a shop towel to provent splashing of fuel caused by residual pressure in the fuel line.
Install the Fuel Pressure Gauge Adapter (09353-38000) between the delivery pipe and the fuel feed hose.
Connect the Fuel Pressure Gauge Connector (09353-38000).
Connect the Fuel Pressure Gauge and Hose (09353-24100) to the Fuel Pressure Gauge Connector (09353-24000)


Connect the fuel feed hose to the Fuel Pressure Gauge Adaptor (09353-38000) Fuel pressure gauge to fuel delivery pipe 25 - 35 Nm (250 - 350 kg.cm, 18 - 26 lb.ft)
Connect the battery's negative (-) terminal.
Apply battery voltage to the terminal for the pump drive and activate the fuel pump: then, with fuel pressure gauge or connection part.


Start and run the engine at curb idle speed.
Disconnect the vacuum hose from the pressure regulator, and plug the end of the hose. Measure the fuel pressure at idle. Standard value: 320 - 340 kPa (3.26 - 3.47 kg/sq.cm, 46 - 49 psi)


Measure the fuel pressure when the vacuum hose is connected to the pressure regulator. Standard value: Approx. 255 kPa (2.57 kg/sq.cm, 37 psi)
If the results of the measurements made in steps (7) and (B) are not within the standard value, use the table below to determine the probable cause, and make the necessary repairs.


Stop the engine and check for a change in the fuel pressure gauge reading, which should hold for approximately 5 minutes . If the gauge indication drops, observe the rate of drop. Determine and remove the causes according to the following table.
Reduce the pressure in the fuel line.
Disconnect the hose and the gauge. WARNING: Cover the hose connection with a shop towel to prevent splashing of fuel caused by fuel residual pressure in the fuel line.
Replace the O-ring of the end of the hose.
Connect the fuel hose to the delivery pipe and tighten with the specified.
Check for fuel leakage.


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