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.

Back to the lab again....

Love the new wiring boards, more in depth, more real. Didn't take to long to wire everything up and working right but I didn't do it right according to the diagram, so I had to rewire. Made my 30 on the relay always hot but that's not how the wiring diagram had it. It actually is a switched ground so had to do some backtracking. Found a video on YouTube that explained the basics of a dc motor. Never knew that the polarity jumps back and forth, but that's why were in school cause we don't know everything. I didn't expect some of the current flow readings i got either but i will update on that.

More Power

This week was good as always at the IMCO dominion. Ran into some differentials coming to the end of their journey, so got a chance to rebuild one. A lot of maintenance this week as usual. Friday was supposed to be an early day, but around 1 o'clock, an F450 comes in with a trailer. Half of the lights on the trailer are not working, electric brakes not working, brake controller not working. Sweet early Friday huh. The plug on the trailer was filthy and my readings at some of the lights were at zero. New plug and a couple of new wires and the trailer lights are working but still no brakes. I started to check the wires running to the controller in the cab, nothing at always hot, no ground, no switch power, no way. Had a fun time locating fuse diagrams on the net. All the fuses were good. Couldn't locate any schematics so I began the chase. By 4 o'clock I was under the dash searching for clues when I found an empty plug with identical wire colors. It had a ground, a healthy 12 and a switch power that was up and down when I hit the brakes. I found my plug. Whoever wired the brake controller must of been a genius. It was a good Friday after all.

The IMCO way

 Been with IMCO for a month now and I'm enjoying everyday of it. The past couple of weeks have been a lot of electrical work. Had some horrible wire corrosion and weathering. Had a hydraulic vacuum arm not responding on a sweeper but after jiggling some wires it started working. I love how we go about fixing it though. There is no just fixing that one terminal or wire. I tore out the whole bundle, marked them all thankfully, and then after finishing sprayed any terminals down with a clear film to keep the elements out. We bought some new F350s last week so I got to put all new accessories on them. Installed new headache racks on them and ran wires from the cab aux switches to the strobes, fuel tanks and work lights. Also tore out the old trailer plugs and retrofitted some different style ones. In between all that just kept hacking away scheduled maintenance. Got a chance to take a couple of pics. One of them is of a dirty carburetor off of pipe fitter that didn't want to start, now it starts and runs. The gunk on the pad was inside the carb.The other is an actuator for a vacuum door for a sweeper. Apparently someone smashed the housing which let the elements in and killed the gears inside. Got a new one, there was no way of saving it, the motor burned up. And the last one has nothing to do with work but I went to some garage sales to look for tools and saw this tag on a tent for sale. People either need to learn how to spell or this was inappropriate for a g-sale.

Getting my feet wet

I've been having a blessed summer. Got a job with IMCO general construction. First three weeks have been exceptional. The whole idea of preventative maintenance has been set more in stone. We have 1-ton pick ups with well over 200k on them and still purring. Every dump truck, lowboy, pick up, excavator, generator, and other machinery has maintenance interval stickers on them. Like with any construction company though the equipment gets thrashed. So we get to do everything from transmission swaps to body work, to modifying vehicles for different tasks. Ran into some electrical problems, nothing too crazy but if I didn't know how to use my multimeter I would of been in the dark. Mostly bad grounds and loose connections, nothing that some good cleaning, splicing and heat shrink can't fix. I get in about 40-45 hours weekly. So I got about +-120 hours so far. (Will try to get some pics up soon, haven't been taking many though.)    

Brakes

http://youtu.be/u7kImGcBUZE

Electrical/Electronics/Etc...

If I cant do it, I cant learn it. If I cant learn it, I cant do it. Get it. Good. I did A LOT of mechanical work on vehicles since I was a kid. Never got into any of the electrical. My brother did, I didn't. Anytime I looked at a multimeter or a wiring diagram my mind went uhhhhhhhhh, yeahhhhhhh. I kinda always thought I wouldn't be able to grasp it. I'm glad I could prove myself wrong. First off I learned that there are 3 possible scenarios where an electrical circuit can fail. Open, short and high resistance. Boom simple. We learned by eliminating two and tracking the one. By eliminating what the problem isn't, we can concentrate on the "is". I don't think Jeff just wanted us to figure out a whole bunch of electrical boards. If I did it 2 or 3 times I'm not learning, 30, 40, 150 times now if I can do it I can learn it. I think he did it to imprint a way of troubleshooting by filtering, by separating the flyspecks from the..... oh you know how it goes.

Mind Set (mine-is-set)

Don't want to sound like one of those motivational posters but I believe the mindset you go into learning with, is going to be the same when you are done. The first couple of days of this this quarter I honestly tried to be as open minded and positive as possible. I believe its helping me learn and achieve goals that I wouldn't if i had the wrong approach.  

Day Uno

You don't know anything about electricity until you get shocked once or twice.