SureTrack Real Fix: No Fuel, No Start

If your engine doesn’t get any fuel, it’s not going to start. There are many reasons why this might happen. Follow this Real Fix to see how a damaged harness was the cause of a no start condition on this Mazda.

Vehicle
1992 Mazda Protege DX 1.8

Title
Engine Does Not Start, Repaired Mass Airflow Sensor Wiring Harness

Complaint
The customer states the engine will not start.

Cause
Confirmed the customer’s complaint and found the engine did not start. Performed an inspection of the engine compartment and found no obvious defects. Connected a spark tester to spark plug wire #1, cranked the engine and found spark was present. Connected a fuel pressure gauge to the fuel filter outlet, tested fuel pressure with the key on and engine off, and found the measured fuel pressure was below the specified range. Used a multi-meter to check for the presence of voltage at the fuel pump and found voltage was not present. Used a fused jumper wires to apply voltage to the fuel pump, and found the motor was responsive and the engine started. Used the multi-meter to check for the presence of voltage at the input terminal of the fuel pump relay and found voltage was present. Used the fused jumper wire to bypass the fuel pump relay and found the fuel pump was responsive. Used the multi-meter to check for the presence of voltage and ground at the control circuit of the fuel pump relay, and found ground was not present. Wiggled the mass airflow sensor wiring harness and monitored the multi-meter. The fuel pump relay ground observed on the multi-meter was affected as the mass airflow sensor wiring harness was wiggled, which indicated a circuit fault was present. Visually inspected the mass airflow sensor wiring harness and found the harness was damaged, preventing the fuel pump relay from activating.

Correction
Repaired the mass airflow sensor wiring harness and verified the vehicle operated properly. The customer’s concern did not return.