Vehicle safety report

Students from PS 2014, Physics: Heat, Light, Electricity, and Magnetism, and one instructor ran the twice-yearly Vehicle Safety Day on Wednesday, April 24th between 12.30 and 4.00pm at the workshop in the Unity House garage.

Only fifteen vehicles were examined. It seems very unlikely that driving has suddenly and very markedly dropped in popularity among Unity College students, or that all students are now rich enough to buy new vehicles that don't need to be checked out.

There was an error in the Head Grease Monkey's original announcement of the date, which may have contributed, although further emails corrected the error. The somewhat cold, gloomy weather may have contributed to the decreased demand. But there must still be many vehicles that need to be inspected.

We want you to be safe. If you planned to get your vehicle checked and were not able to because of the email error or for some other reason, email mwomersley@unity.edu and ask for an appointment.

Most safety checks were routine. The following specific problems were noted, and are reported here so other vehicle owners can learn from them. If you can't afford a brand new car, but want to get around reliably, you need to begin building some knowledge about automotive technology, even if it's just knowing when to take it to a shop! Students that want to learn more about mechanics and vehicle maintenance can now sign up to take PS 1003, Practical Mechanics and Carpentry, every second fall. It will next be offered in Fall 2020.

1. Several vehicles had the check-engine light on and so reported  "trouble codes", which were "pulled" and recorded for the owners to seek further help. Some trouble codes can be more or less safely ignored, but not all or even most. Even if you choose to ignore one, it's best to check it periodically to make sure a second code has not been triggered.
2. The "Maintenance Required" light is not the same as the "Check Engine" light. Maintenance Required lights come on when scheduled servicing is due every six thousand or so miles. They can be turned off after the servicing is complete. Read the vehicle manual to find out what needs to be serviced at each stage, and how to switch off the vehicle maintenance light when servicing is complete. Usually you have to press the trip meter button for ten seconds while touching your nose, only if there's a R in the month. (Just kidding. But there is usually some combination of buttons to press that turn the light off.)
3. One fuel-injected vehicle had an intermittently flashing "Check Engine" light and a rough or "lumpy" idle. The codes were "pulled," reporting PO300 "multiple generic misfire" and PO301, 302, 303, 304, 305, and 306: Misfires in cylinders 1 through 6 respectively. These are standard codes that might appear in any post-1996 vehicle with onboard diagnostics (OBD). Although the Engine Control Unit (ECU - the vehicle's computer) registered the fault in the ignition system, this series of codes is unlikely to be an ignition- or even a fuel-injection related misfire. It would be unreasonable to assume that all the independent coil packs for each cylinder developed an identical electrical fault simultaneously. And if this were a fuel-related misfire, there would likely be some indication of that in some other code, or in the ECU data stream (lean fuel mixture, for instance). Most likely there is some problem with the exhaust gas recirculation, vacuum, or intake air systems, any of which might cause increased air supply at idle, making the vehicle run rough. Systematic troubleshooting of these systems will ultimately reveal the fault, but it would help to have spare parts available to switch out experimentally. Dealerships often keep spare parts for popular vehicles for this purpose, as well as marque-specific code computers, so the dealership has an advantage over the local mechanic for determining this otherwise hard-to trace fault. A lesson on that, as an aside: There is no engineering problem in the world that can stand up to systematic scientific troubleshooting. There are faults that are not cost-effective to fix, and there are faults we don't have time to fix, but there are no un-fixable faults in engineering technology.
4. One vehicle was examined for a high speed vibration, AKA "death rattle" (for good reason), after hitting a pothole. No obvious fault was found, but one front wheel was suspected of being over-cambered, in other words, out of alignment. This vehicle is unsafe, needs an alignment, and should not be driven above fifty mph. It might even be best to have it towed to the alignment shop. Don't drive a vehicle that has a "death rattle." You might die.
5. Two vehicles had noisy exhaust systems. We were able to put the vehicles on our lift and find the damaged parts. This could save the owners a little money, as they both plan to repair them themselves, and now know which parts to buy.

Thanks to all the students who assisted with this activity, as well as the Student Affairs and Maintenance Departments.

Drive safely, please,

Mick Womersley

Professor of Human Ecology

Head Grease Monkey