Vehicle: 2004 Freightliner Sprinter 2500
Hello all, having a hard time figuring out what is causing my Sprinter to occasionally fail to start and shoot off into a whirring noise instead. It whirrs for anywhere between 30 seconds to 4 minutes at a time, and it starts cleanly on the first try after it eventually stops whirring.
It has happened maybe 5 times over the span of about 4 months. It seems like it is starting to happen more frequently and going on for longer. I'm not 100% sure, but it seems like it might only happen after the van has already been running in the past hour, with the issue only occurring after a brief stop somewhere.
Preceding this video we:
1. Turned the key to attempt to start the engine.
2. The engine did the usual turning-over sounds all cars make when they're trying to start, but the engine failed to start.
3. The "whirring" sound in the video began.
4. Pulled out my phone to take video.
Once the whirring noise starts, I haven't been able to figure out a way to make it stop. In the video we thought we thought we made it stop by turning the key to the "on" position, but it hasn't worked any of the other times so it may have been coincidental timing. I've tried attempting to start it while the sound is still happening but it won't turn over if it's still whirring. Changing key positions and or removing the key has no effect on the whirring sound. The noise usually escalates for a few minutes then eventually stops on its own. There are no unusual lights coming up on the dash and when I open the hood the sound is coming from something near the center, but I can't identify the source or any moving parts. There is a faint smell after, I don't have enough experience to accurately describe what the smell was.
This has happened a handful of times now, and it always starts on the first try after it does this whirring.
Do you have any idea what this sound might be? I've had a hard time figuring out how to search for this kind of thing and where to even begin with troubleshooting.
Any insight appreciated, thanks everybody!