It is a sad reality of our industry that the understanding of internal combustion engines and their governing principles is becoming a lost art with today’s automotive technicians.
As a kid in the 1970s I enjoyed learning engine basics in school. Remember? Four strokes: Intake, Compression, Power, Exhaust. We also covered two-strokes engines, rotary engines, carburetors, ignition systems, etc. Somewhere I still have my old textbook and I can remember the large color-pictures of spark plugs showing spark plug conditions as a means of basic engine diagnostics. Black plugs?: running rich. White ash-like deposits?: running lean.
In the defense of today’s automotive technicians: to say engines technology, by the 1970s, was primitive compared to today’s engines is a gross understatement.
In the 1970s you needed three things for an engine to run: compression, fuel and ignition. The tool of the day, ignition analyzers in huge rolling cabinets, would give a professional technician an ignition spark pattern on an oscilloscope screen (CRT or cathode ray tube display). This spark pattern could be captured in minutes and interpretation of the spark pattern on the CRT gave the tech comprehensive insights into the combustion chamber behaviors while the engine was running. It was a pretty simple and very powerful system of determining what was wrong with an engine. Within minutes a rough-running engine’s ailment was typically pinpointed.
This worked well for one reason: fuel and ignition systems ran pretty independently of engines. With carburetors fuel delivery was proportional to engine air intake. Some engines had crude input systems to adjust carburetor behavior based on engine temperature or engine load but, on the whole, carburetors had little ‘knowledge’ of the engine’s running condition and performance. So too of ignition systems – high voltage ignition spark signals were sent to each spark plug with little to no knowledge of engine running condition.
So what changed? Everything.
Today’s engine produces significantly more power from the same amount of fuel, it starts and runs much better, produces much cleaner exhaust, while also enjoying large advances in weight reduction, production cost reduction, etc, etc.
These advances are largely credited to advances in the field of “Engine Management” – a term that really didn’t exist in the 1970s.
Engine Management, thanks to computers, creates a much more dynamic relationship between combustion chamber conditions and both ignition and fuel system responses. Net effect: ignition spark analysis cannot be relied upon solely to provide answers to engine performance problems.
The good news is engine management systems, being computer systems, can provide insights into what is wrong with an engine by allowing technicians to see the data the computer management system can see.
Bad news: the complexity of problems is multiplied by the potential for bad data AND the computer’s response to it. EG: Do we have a lean running engine because the computer system thinks (incorrectly) that it should be commanding a lean condition? Is the lean condition a condition that the computer system knows exists but cannot correct? Is the computer trying to command a change that the mechanical components cannot suffice?
Worse news: today’s engine’s impressive performance require more precise engine management so something like, say a slightly lean running condition, might have been unnoticed in a 1970’s engine performance can create very noticeable performance problems in today’s engine AND can cascade into other problems / collateral damage.
This relationship between the engine management system and the engine has also caused a dysfunctionality amongst today’s technician. He/she typically reaches for a computer diagnostic scanner, reads codes, and starts to analyze the problem. With any luck the problem can be reproduced, data in the computer management system will respond to the problem, and allow the technician to determine the root-cause. This process, although somewhat time-consuming, often works well.
The problem is: this is such a common approach that the technician tends to forget that underneath the engine management system there is a basic four-stroke engine that obeys the basic laws it did back in the 1970s including the basic need for three things: compression, ignition, and fuel.
When the basics of an engine’s mechanical condition is compromised no amount of engine management based repairs will correct it. Worse – engine management repairs can help manage symptoms of the mechanical problem and deceive the technician into thinking he/she is on the right path to fixing the root-cause.
So – to get around this today’s technician needs to remember the 1970s and diagnose base mechanical conditions of an engine while understanding and compensating for how engine management systems will undermine or skew the results.
How is this done? When we interview technicians to potentially hire them we explore their knowledge of these basics: Engine exhaust analysis / ignition scope analysis / engine vacuum characteristics / compression analysis…
The enlightening part, we have found, is the technician’s knowledge of the appropriate tools:
These aren’t everyday tools and range drasticly in price, but we have found that technicians that understand and employ them appropriately are the same technicians that can fix those difficult problems that frustrate other technicians and motorists alike.
Which, in turn, provides the consumer with the same. Although not always the right path, advanced engine diagnostics, ironically, have solutions often found in the basics and an interview with a shop on their capabilities with the basics will let the client know if the shop can indeed solve the tough problems.
If you’re faced with a difficult Engine Diagnostic problem consider – does your technician have the above tools? Does he/she know how to use them? These are not everyday tools but at Galloping Gertie’s Garage we have made commitments to this type of tooling far beyond the levels most automotive shops so that we can provide answers to the tough problems.
If you think these handicaps are limiting for technician’s with today’s cars try solving tricky problems on yesterday’s cars! Sadly the technician who has never mastered these technologies can only poke in the dark at problems with vehicles that do not have an engine management system to help guide him/her. If you own an old car and need help with engine performance and diagnostics most shops won’t be equipped to help unless you find one with the same commitment to this technology as our shop.
Mechanical conditions dominated old car performance – I suspect that’s why we called their technicians “Mechanics”. Unfortunately the art of mechanic is being lost in today’s automotive technician.