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6810 Misdiagnosis Flyer 2 1 11 1 53 PM Page 1 AIRTEX Product Information Sheet Airtex fuel pumps are 100 tested before they leave the factory That s why it s a good idea to check out everything else first before suspecting the fuel pump In fact 50 of all fuel pumps returned for warranty consideration meet all manufacturer s specifications when tested Nearly 75 of all aftermarket fuel pump failures are caused by Misdiagnosis Vehicle related electrical wiring or connector issues Contaminated vehicle fuel systems Misdiagnosis Misdiagnosis is the leading cause of fuel pump returns If the engine runs but displays driveability symptoms that you suspect are fuel related hard starting hesitation misfiring power loss first attempt to eliminate other possible causes of the problem Make sure the engine is in good mechanical condition An engine may not start or run properly for many reasons BE SURE TO CHECK Fuel in the vehicle tank is adequate add 2 to 3 gallons as needed Fuel is fresh and of good quality Fuel system has no leaks Fuel filter has been replaced Fuel delivery electrical system checks OK Engine mechanical systems check OK Engine electrical system checks OK Ignition system checks OK Charging system checks OK Battery voltage is at least 12 4 volts Cranking voltage at the starter is at least 9 6 volts Inertia switch is reset typical of Ford applications Oil pressure and RPM signals are present various applications THE MOST COMMON REASONS FOR REPEAT FUEL PUMP FAILURE ARE Misdiagnosis Pump is OK fault lies elsewhere Not measuring fuel volume Not replacing fuel filter and strainer s Fuel contamination Not properly cleaning and flushing inside of fuel tank Not correcting vehicle electrical connector wiring and ground issues Not resetting a tripped inertia switch Not checking for oil pressure and RPM signals FUEL SYSTEM Misdiagnosis Fuel Delivery Systems TM 6810 Misdiagnosis Flyer 2 1 11 1 53 PM Page 2 A clean fuel tank is essential to successful fuel pump replacement Rust corrosion or other contamination in the vehicle s fuel tank can quickly cause a new fuel pump to fail Rusty brown or dark colored strainers and pumps are signs that contaminated fuel or a contaminated fuel tank contributed to pump failure The presence of rust dirt scale or slime indicate that the fuel tank must be professionally cleaned or replaced before installing a new fuel pump NEVER REUSE OLD STRAINERS OR FILTERS especially when installing a new fuel pump Fuel filters and strainers assure that the fuel sent to the pump and the injectors is clean The fuel pump fuel injectors and other fuel system components are highly susceptible to damage from minute particles of dirt and contaminants Restricted or plugged filters force fuel pumps to work harder allow less fuel to circulate in the system and contribute to pump overheating and premature failure Typically two filters are used on the fuel system to keep the fuel system clean In tank strainer mounted to the fuel pump In tank strainer must be replaced whenever the fuel pump is replaced or as required by the vehicle manufacturer External inline fuel filter Change inline filters every 30 000 miles or as recommended by the vehicle manufacturer Fuel pump strainer and inline fuel filter replacement does not take the place of cleaning a dirty contaminated fuel tank Remember the Major Causes of Fuel Pump Failure Are Misdiagnosis of the vehicle s problem Rust corrosion or other contamination in the vehicle s fuel tank Clogged or plugged fuel filters and strainers Faulty on vehicle fuel pump wiring or connectors When Replacing a Fuel Pump ALWAYS Replace the filter or strainer with new Professionally flush or clean the fuel tank Inspect repair or replace suspect vehicle connectors and wiring Refer to the Diagnostic Troubleshooting and Installation Guidelines document found in the fuel pump box FUEL SYSTEM Contamination AIRTEX Product Information Sheet Contamination Dirty Strainer Rust Corrosion In Tank Strainer Inline Fuel Filter 407 West Main Street Fairfield IL 62837 Tech Line 1 800 424 7839 2010 Airtex Products LP airtexproducts com AT 6810 F1 Fuel Delivery Systems TM
