Tech Tips (by ALLDATA): Cadillac won’t start after refueling

TECH TIPS (courtesy of ALLDATA)

Vehicle: 2006 Cadillac CTS V6-3.6L VIN 7, Automatic Transmission

Mileage: 72,002

Problem: The customer stated that, no matter how low or full the tank was or how much fuel they added, the engine would crank but not start. If they let the car sit for a few minutes, the engine would start normally and run fine. The malfunction indicator light was not illuminated.


Details: The tech suspected a flooding or excessive vapor issue. He first verified that the fuel tank vent line was clear and allowing pressure to escape while refueling. It was open.

Next, he removed the vacuum/vapor line that leads from the purge control solenoid to the vapor canister and disconnected the electrical connector to eliminate a possible purge commanded at idle. The tech filled the fuel tank and tried to start the engine. Because there was no vacuum to the valve, there was no fuel vapor flowing through the purge control valve from the canister to the intake manifold. The engine started normally.

Confirmed Repair: The tech verified that the purge solenoid was faulty by applying power and ground to the solenoid. With power to the valve, it opened. With power off, the valve was still open. He replaced the purge control solenoid and the problem was resolved.