The HC Detective

Today’s topic is technology. The modern automobile is the most complex piece of technology that most individuals interact with on a daily basis. Modern vehicles can have up to 60 modules (computers) on board communicating on several networks and can communicate with other vehicles in close proximity. For example, if a vehicle drives over a slippery spot in the roadway and the Traction Control Feature is activated, that information is relayed to other vehicles in the area to alert them of the potential danger. Drivers are unaware of vehicle to vehicle communication and the actions taken to keep them safe.

Today I would like to discuss the Five Gas Analyzer. The probe you observe in a tailpipe during an emission test is attached to the analyzer. The analyzer samples and displays the values of the five tailpipe gases in percentages or parts per million (PPM). Understanding the relationships between gases – how and why they are formed – diagnostically tells us nearly everything we need to know to start our diagnostic in the proper direction. Collecting and entering those gas values into a Lambda Calculator is diagnostic on steroids when evaluating the fuel injection, secondary ignition and the efficiency of the Catalytic Converter and combustion process. The Five Gas Analyzer is INDISPENSABLE for the proper diagnosis of emissions and drivability problems.

Today’s primary topic is the untraditional and innovative ways we use five gas technology to advance diagnostics outside of emissions. One of our largest competitors sends us a lot of referrals. When they suspect a blown head gasket or cracked cylinder head they perform the traditional “Block Test.” If the vehicle fails the test the customer is referred to us. Their diagnosis has a high rate of inaccuracy, much to the relief of those customers. We use our Five Gas Analyzer. When a head gasket loses its seal or the cylinder head is cracked, the gasoline/hydrocarbon (HC) vapor in that cylinder is leaked into the cooling system during the compression event. Those air bubbles collect at the highest point in the cooling system: the radiator neck. With the radiator cap removed, we sample that gas. If HCs are present, we have a sealing problem. It’s quick and accurate.

Another untraditional way we use this technology is when customers complain of gasoline fumes in or around the vehicle. I move the emission probe over the engine, down the fuel rails and fuel supply lines, on top of the fuel tank and over the vapor canister while watching the analyzer monitor. Once HCs are displayed, I just keep working the probe until I find the highest concentration. I do not have to smell the leak in order to find it. The five gas technology puts me on the complaint quickly and accurately.

Last week I was battling a 1994 Nissan Maxima with a misfire. My diagnostic lead me to believe I was dealing with a defective fuel injector. The problem was my fuel injector was under the intake manifold and labor intensive. I wanted to be reasonably sure the misfire cause is insufficient fuel before I invest that much time. I removed the spark plug and inserted the emission probe. I started the engine and monitored the HCs. Only 35 PPMs displayed. A good injector will display HCs in the 5,000 PPM range and above. A new fuel injector solved the problem and the Maxima easily passed its smog inspection.