This is not something I'm worried about. I just want to know what exactly it is. When you turn the key once without a start, I can hear something mechanically turning on like a compressor or a pump. Anyone know what that could be. Like I said I'm not at all worried, just wondering.

 

My guess is fuel pump is cycling but don't quote me on that

 

Fuel Pump

 

That is you breathing heavy in anticipation of the fun that is about to explode under your control....or could be just the fuel pump.

 

Hahaha. I hear it all the time. It's a loud thumping in my chest. Weird...

 

^ this.

In fact, if you own any car in the last decade or so (or older maybe), they all do that.... just have to listen.

 

Fuel Pump.

This is also why, if you release pressure in the fuel line for any reason, it is recommended to turn the key to ON for a few seconds, then OFF - and repeat three or four times to build pressure in the fuel system back up.

 

Amen to the fuel pump!