Finals

This week was our final exam for Electronic Diesel Engine Controls. Heavy emphasis on the test was put on use of electronic service information, wiring diagrams, and using a scan tool in conjunction with service information to troubleshoot sensor and wiring problems.

Late-model Freightliner Coronado, used to pull a code for bad turbo intake sensor for our final exam. Our teacher had simply unplugged the sensor.

Reflection:

With finals over, it gives a lot of time to reflect on all the lessons learned and experiences had over my 3 years in the Auto-Diesel shop. My education was not just a matter of learning how to wrench on vehicles. It was learning how to be confident in my abilities and get engaged, even if I make mistakes. It was about interacting with and getting along with my class mates, my teachers, and potential customers. It was about building a pathway to my career.

What is next for me? Tomorrow I go full time at my current place of employment, and say good bye to the Auto/Diesel shop which I have called home for 3 years. This isn't the end, it is just the beginning. I will stop by whenever time permits to see how the place where I got my start is doing, and I will keep my instructors informed of my activities in the Automotive/Diesel Truck world on a regular basis.

It has been, quite an experience!

GMC Sierra 5.3L Final Assembly

This week in class, with permission from my instructor Jeffrey Starkey, my team worked on my GMC Sierra 1500, which was in the shop for repairs originally as part of another class which I helped with. It has a 5.3L gasoline engine, but for the purposes of our class it is very much "electronic engine controls," even if not a diesel. It had been my hope to get the truck finished that day and pulled out of the shop.

Most of the engine work had been done, all that needed to be finished on it was valve covers, the radiator fan, coolant hoses, and of course... electrical connections to sensors and other electrical components. Final step was engine oil and coolant (which we used water to flush the system).

We got everything hooked up and started the truck. Whoops! Coolant leaks everywhere, and a bad idle. What did we do wrong?

This engine has four blocks with little nipples that go into coolant passages on the heads, two on front and two in back. The front ones are passages for the "coolant air bleed pipe" which connects under the throttle plate to the intake and allows air to bleed out of the cooling system. The rear two are simply there to block the flow of coolant out of the heads.

In my haste to get this vehicle finished, I had put the gaskets to these on wrong, and coolant was leaking out of all 4. Lesson learned! We luckily just had to take them back off, put the gaskets on correctly, and we also put some RTV silicone on them just to be sure of correct sealing.

I drove the truck onto our alignment rack, and found it died on me several times. On Thursday, we found this was due to the MAP sensor not being plugged in.

On Thursday, we fixed these issues and finally got the truck running decently and pulled out of the shop.

First ignition after we fixed the leaks and the MAP sensor was plugged in.

Reflection:

Don't get in a hurry. It's not a race. Take the time to go through your work and ensure it is all correct and up to spec. I made some mistakes through being in a rush and learned well from those lessons

The truck still has some issues which need to be ironed out, such as a misfire. However the big work is done. Just a matter of working out the kinks that were probably not related altogether with the crack in the head we fixed, and as always the learning will continue.

Series 60 Crank/No-Start Diagnosis

This week since my team was absent, I was asked to help a member of another team finish diagnosing a Series 60 with a Crank/No-Start condition. We had a clear hose hooked up from the fuel filter to the transfer pump, which I noticed at starting had little more than air in it.

We also noticed that the filter itself had no fuel, so we put fuel in it and tried starting it again. We found air bubbles forming in the (clear) filter housing. After referring to service literature we found this meant an air leak anywhere between the fuel tank and fuel filter, with perhaps defective housing o-rings. Fuel is sent to the transfer pump past the filter.

Checking, we found one o-ring missing from the small fill cap at the top of the filter. We replaced this. Upon startup, we made more progress but we still had significant problems and the truck would not start.

So I crawled under the truck and started at the fuel tanks tracing the lines back. And this is what I found:

Each line comes in from the fuel tanks to this fitting, and goes out to the fuel filter from there.

At first I noticed a wet spot on the fitting, and after touching it found the line to be loose. I tightened it up and we tried again. This time, we got the truck to start.

Reflection:

Problems can have more than one cause. In our case, and agreeing with our service information, there were 2 causes of this no-start condition and we could not get the truck to start until we fixed both of them.

It made sense to get under the truck and inspect the lines and fittings going to the filter, especially after replacing the missing o-ring did not fix the problem. After we had made sure all was okay, we could verify our fix and move, if necessary, to the next step of diagnosis if we still have issues.

Oil Pressure Sensor Circuit Fault, Code 141 (Cummins N14 Celect Plus)

This week in the shop we did some cleanup. Pretty standard stuff, but while looking for a magnet I found this:

Mechanic ingenuity?

Someone had welded a socket to a long piece of all-thread. What the purpose of this tool was I did not learn.

What I did learn, however, was how to read flash codes on a Cummins N14 Celect Plus in the school's International sleeper truck. Courtesy of some quick research on Cummins Quickserve and Google, we ascertained exactly how to read the code flashed on the dash, and found one code, 141. Once again with the help of Google we found this to be an oil pressure sensor circuit fault. So we printed out a component location diagram and went to look:

Oil pressure sensor location. Right under the ECM on the driver's side, mounted in the block.

The actual sensor on the vehicle.

When we checked the sensor, it was unplugged. Mistake from a previous team? Deliberate bugging? Who knows, but once we plugged the sensor back in, the check engine light went out and we were good to go.

Reflection:

Once again we get back to "keep it simple, stupid," the sensor was simply unplugged. However, that might not have been the only problem with it. So what is the next step in the repair process? Verify that the seemingly obvious fix did indeed correct the problem. In our case, it did. But what if there were wiring issues down the line? Then the diagnostic process would continue, with one possible cause (disconnected connector) eliminated. That would have been our next step, had the check engine light stayed illuminated.

The Importance of Maintenance

This week, due to class cancellations, I will briefly post on something I did at work.

While working on a truck for another issue, it was necessary to unhook the batteries. Part of "modus operandi" where I work is to clean pretty much everything we remove if we are putting the same parts back on. So while I had the battery cables disconnected, I went through all the terminals and cable ends and cleaned them all up. Here is what I found on some of them:

I bead-blasted the cable ends and cleaned the nuts for the terminals up on a wire wheel. We had to replace one cable end because it was so badly corroded.

Reflection:

It's good practice to get into the habit of routinely checking and cleaning things such as battery cables and terminals, especially if you have to disconnect them to work on something else anyway. I routinely clean any electrical connections such as this whenever I have them off. It may take an extra minute or two, but it helps to solve a lot of avoidable electrical problems which are the result of the "green" corrosion pictured above.

Rigging A Rig

This week in class my team was responsible for rigging several different engines to have "issues." It is the responsibility of the other teams to successfully diagnose those issues and get them running again. All of these engines were confirmed to run before we rigged them.

Cleaning up the Jake brake connectors on our Series 60 dyno engine, as the engine brakes will not be put back on for now.

Another interesting development of the week was an in-class presentation. No, I don't mean power point slides. The team working on the no-start condition experienced by the Series 60 in the FLD Freightliner was asked to present their findings, in their own words, to the instructor and the rest of class. So far we have determined that the starter relay may have an issue, and they swapped another one in.

I removed this starter relay off one of our stand-engines for the other team to put on the FLD.

This engine started, but now won't. I wonder why? Well, that is for the next team to figure out.

Finally we hooked up a clear plastic hose between the fuel filter and the transfer pump.

Why would we do this? What don't we want in the fuel system after the filter? This is for the next team to answer, or perhaps a class demonstration.

Reflection:

Instead of solving problems, my team has been causing them. But we did not just rip and tear, we strategically bugged these engines. In order to do that, we need just as much understanding of the system's operation as a technician fixing the problem would.

We could fix what we broke in a few short minutes, but it may take another team 30 minutes or an hour or more to even find where the problem is.

Diagnostic time, that is finding where the problem is in the first place, can be the vast majority of the time it takes for a repair. The actual fixing, part replacement, etc. etc. can be a tiny fraction of the work done.

Capstone Project

Background In Mechanics

For the capstone project, it was requested that I provide a little background of how I ended up where I am, and what experiences I've had working in the real world among other things.

To start off, I had never worked on vehicles before my decision to go to school for it. I originally went to school and trained to be an electrician, and it was only after working in the field did I realize it wasn't for me. A morbid fear of heights, coupled with a lack of any serious passion for the field, left me wanting to change direction while I still had the opportunity.

So I researched several different career paths to suit my needs, and the one that struck me immediately was being a mechanic. I researched the field more, including expected income and job descriptions. I watched YouTube videos of people like EricTheCarGuy. Finally, I made the decision to enroll in the WSCC Automotive/Diesel Truck program. The rest is history, as I have been there for 3 years and am set to graduate with Associate's degrees in Automotive Service Technology and Diesel Truck Systems.


Working In The Field


I have been employed by an independent automotive and truck repair shop now for about two and a half months. We work on everything from cars to class-8 trucks, everything from brake service and oil changes to engine swaps and rebuilds, diagnostics and driveability issues. Below are a few pictures of projects we've been working on recently or currently working on.

International 9200i. Earlier that day we had everything up to the gear housing off to fix a leak.

Transfer case my boss is working on off another truck.

Still waiting on the turbo for the 9200i, which is being replaced.

Cleaning up ground terminals with emery cloth before hooking them back up to the radiator support.

About to replace the park brake valve on a Chevy single-axle dump truck.

 

The new valve installed with compression fittings. The trailer valve was removed as the customer will not be pulling a trailer with this truck.

As you can see, there's a wide variety of work we do. The opportunities to learn something are there on a daily basis.


Tool Selection

Something that has been of particular interest to me since gaining employment in the field is tools. Our shop is visited by S&K and Snap-On tool trucks.

I picked this up from an auto parts store for $5.

The above pictured tool measures bolt and nut sizes on any standard 6-point head in both standard and metric. Until my ability to tell bolt size at a glance gets better, this tool has become a huge time-saver.

My first major tool investment, a set of Grey Pneumatic Duo-Sockets in 3/8" drive. I also bought a 1/4" set. Thinner than regular impacts, they are made and warrantied for use an air impact tools.

My tool purchases have been heavily influenced by what I need on a daily basis. Better lighting, sockets, ratchets, wrenches, are among my first purchases. Tools that come in handy or I tend to borrow from my co-workers a lot are also on the list as I build my toolbox up.

I had these before I started my job, punches and chisels are something I use all the time.

Other good examples of tools I would have or get sooner rather than later are pry bars, flat head screwdrivers, scrapers, hammers, extensions and swivel sockets. The list could go on. All based on what I find myself needing in the shop on a daily basis.