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How to Check for Fuel Delivery in a Hyundai Sonata

by Contributor; Updated November 07, 2017

How to Check for Fuel Delivery in a Hyundai Sonata. The Hyundai Sonata is a four-door, mid-sized family sedan that debuted in the United States in 1989. The Sonata incorporates Mitsubishi engineering, including the Mitsubishi Sirius engine. The Sonata was named Kiplinger's Personal Finance "Best in Class" in 2005 and 2007 and Consumers Digest "Best Buy" in 2006.

Check fuel delivery in the Hyundai Sonata if the engine runs rough, stalls in traffic or doesn't start at all.

Relieve fuel system pressure. Take the back seat cushion out and remove the access panel underneath to disconnect the connector for the fuel pump module. Start the Hyundai Sonata and let the engine run until it stalls from lack of gasoline. Turn the ignition off and disconnect the negative battery cable.

Disconnect the fuel pressure sensor vacuum hose. Check for fuel in the line. If there is fuel present in the line, the fuel delivery problem is likely caused by a faulty fuel pump pressure regulator. If there is no fuel in the line, reattach the vacuum hose and continue with the fuel delivery diagnostic.

Twist off the fuel pressure test port cap and secure a pressure gauge to the fuel pressure valve. Reconnect the negative battery cable and start the engine. Disconnect the vacuum hose again and check the gauge. It needs to read between 38 and 50 pounds per square inch. High pressures indicate that the pressure regulator is malfunctioning. Low pressures indicate that the fuel filter is clogged or that the fuel pump needs to be replaced.

Cut the engine. Relieve system pressure and remove the negative battery cable again so you can safely remove the fuel filter to check for clogs.

Loosen the filter fittings and unhook the pressure and fuel lines from the filter. Undo the bracket on the fuel filter and take it out.

Inspect the filter for clogs and replace it with a new one if necessary. If there are no clogs, the fuel delivery problem is due to a faulty fuel pump.

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