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How to Check for Fuel Delivery in a Nissan Altima

by Contributor; Updated November 07, 2017

How to Check for Fuel Delivery in a Nissan Altima. The Nissan Altima compact vehicle debuted in 1993. In 2002, the car's design shifted to a midsize, four-door sedan. A two-door coupe variation was released in 2008 and as a hybrid, using hybrid technology developed by Toyota, in 2007. Investigate the fuel delivery system in a Nissan Altima if the engine won't start, if it starts running rough or stalls out in traffic.

Relieve the pressure in the Nissan Altima model's fuel system. Disengage the fuel pump fuse. Start the engine and let it run until it stalls. Turn the ignition to the off position 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 probably due to 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 use a "T" connector to attach a pressure gauge to the fuel pressure valve. Open the manual valve on the gauge and let the fuel drain through the connected tube into an approved container. Reconnect the negative battery cable and start the engine.

Check the pressure gauge. It needs to register approximately 34 psi. Pressure that's too high indicates a malfunctioning pressure regulator. Low pressure indicates a clogged fuel filter or a broken fuel pump that needs to be replaced.

Cut the engine, relieve system pressure again and remove the negative battery cable.

Remove the filter and the fuel pump combo assembly. Disconnect the electrical connector to the pump located under the back seat. Disengage the fuel lines that run to the pump. Disengage the locking ring and assembly for the fuel gauge. Disconnect the fuel gauge from its tube and connector. Lift the pump straight up out of the fuel tank by pressing the two locking tabs together to release the holding bracket.

Examine the filter for clogs and replace it with a new one if necessary. If there are no clogs, the fuel delivery problem is probably caused by a faulty fuel pump.

Warnings

Relieve fuel pressure before you disconnect fuel injection-related components. Don't let any fuel come in contact with engine or electrical components. Don't operate the fuel pump for more than a couple seconds if you connect the fuel pressure gauge to the fuel system without a "T" connector. Using the fuel pump any longer will cause damage to the fuel pump.

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