Sensing something?

Starting to wrap my head around sensors. The one i got in class is a fuel tank pressure sensor that fits almost any GM vehicle. The tank is supplied with a certain pressure, the sensor can recognize any change in that pressure. Things like the gas cap being open or the EVAP purge valve stuck open will tell the ECU the drop in pressure which throws the check engine light on. This is not as much of a drive-ability issue as it is a environmental issue. It is a 3 wire sensor, 5v reference, output and ground.Its quite easy to test this sensor by applying 5v to the reference and a 12v ground. Then you simply blow into the tube and see if your output volts fluctuate from 0.1v to 4.9v. I ran into a problem at work where the oil pressure gauge was not showing any pressure. So I started barking up the wrong tree when I saw only 5v going to the sensor, so after some pointless wire chasing I gave up and went to the internet and that's when I learned about the reference volts. The truck needed a new sensor and it was all good from then on. I also liked the trick we learned that by disconnecting sensors you can find out which ones they are on the scan tool.

Confidence

What I love most about engine work is how the concept of combustion engines is the same but once you get into them you start to observe how differently each one was designed. Besides the Mercedes engine we disassembled at school with the guys, I got a chance to swap out head gaskets and install various aftermarket components on a 6.0 International at work. My foreman told me that whatever my interpretation of meticulous is, to double it. When everything was finally put back together, it wouldn’t start for a good 15 minutes, made me quite nervous. When it finally did start and we took it for a test drive the turbo lag vanes broke and we lost all boost. Put a new turbo on it and it has been running good since. I guess what I learned the most is to have confidence in your work because if don’t you will get overwhelmed with doubt. On another note the lethal injection video was nasty but very informative. Even though the chances are very low I think anybody working on any sort of hydraulic system should be aware of the dangers involved and what to do if something did happen.