Info - Proper Diagnosis of Fuel System Concerns - Engine Cranks But Does Not Start, No Start

The purpose of this bulletin is to assist in properly diagnosing conditions related to the fuel supply system.

When diagnosing a condition where the engine will not run, always start with the "Engine Cranks but Does Not Run" chart (SI Document ID #1486823). Once it has been determined that the PCM has power and spark is detected, the chart leads to Fuel Pump Electrical Circuit Diagnosis (SI Document ID #1487572). Following this chart determines if the electrical control circuit is operational before checking pressure and output of the pump. It is very important that this step be performed. Poor contact within the electrical terminals will prevent the fuel pump from operating properly.

Part of the inspection process for determining if there is good terminal contact is to insert the correct probe into the female terminal and feel for resistance. Little or no resistance indicates there will be poor contact in the connection and lead to fuel pump output concerns.

Important: Before removing the body electrical center cover, lift and move the harness upward that lays across the top of the cover. When removing the electrical center cover, lift the cover straight up and out to avoid dislodging or possibly damaging the electrical components.

Notice: Use J 43244 to pull the relay straight out from the electrical center terminals. The use of pliers or a flat bladed tool could damage the electrical center.

Begin by removing the fuel pump relay from the electrical center using the J 43244 relay removal tool. Position the tool on opposing corners of the relay.

Notice: When inserting the probe, care must be taken to insert it straight into the terminal and pull it straight out of the terminal as misalignment will cause damage to the terminal.

Using the J 35616-35 (purple) probe from the J 35616 Probe Kit, check for proper contact by inserting it into each of the 4 fuel pump relay terminals (A1, A3, B1 and B3) in the electrical center. Any terminal that does not produce sufficient resistance must be replaced using the Repairing Connector Terminals procedure (SI Document ID #325249). The part number for the fuel pump relay terminals is 15324340 and are included in the J 38125 Terminal Repair Kit.

After checking the terminals and making the necessary repairs, inspect the relay terminals to be sure they are not twisted or bent. If any of the terminals are damaged, replace the relay.