Troubleshooting a car that won’t start after connecting a diagnostic scanner can be frustrating. This article explores a specific scenario where a vehicle exhibits extended crank times, requiring throttle manipulation or multiple attempts to start after a tune flash and scanner use. We’ll delve into the observations made during the troubleshooting process, including fuel pressure checks and variations in starting behavior based on wait times after flashing.
Fuel Pressure and Scanner Tests
Initial troubleshooting involved verifying fuel pressure using a gauge. Readings indicated slightly high fuel pressure before starting attempts. Activating the fuel pump prime function within the VCM Scanner didn’t resolve the hard starting issue. Interestingly, the fuel pump priming sound wasn’t always audible immediately after a tune flash.
Timing and Starting Behavior
Further testing revealed a correlation between the wait time after flashing a new tune and the car’s starting performance. A short wait time (15 seconds) consistently resulted in hard starting, regardless of whether only the calibration or the entire tune was flashed. However, extending the wait time significantly eliminated the starting problem.
Read vs. Write Operations
A peculiar observation was made regarding scanner read operations. If a calibration-only flash was followed by a short wait, then a full scanner read of the entire vehicle system (taking 2-3 minutes), the subsequent starting attempt was successful. This suggests a potential difference in how the vehicle’s systems reset after a write (flashing) operation compared to a read operation. The type of flash (calibration only or entire) didn’t seem to influence the outcome. Further investigation into the specific differences between read and write operations within the vehicle’s computer system might shed light on the root cause of this starting issue.
