August 2016 Archives - UnderhoodService
Horn Honks When Door Is Opened

This month’s Diagnostic Dilemma begins with a 2012 Jeep Rubicon that honked the horn each time a door was opened. The call came from a small-fleet diesel tech who also gets his share of his business owners’ personal vehicle problems. Doing some information gathering, we discovered that the horn honked when the door was opened or when the exterior or interior lighting was activated.

Fuel Injector Diagnostics

In the U.S., the quality of the fuel we put into our vehicles is very high. By the time it travels through the fill neck, it has been filtered twice at the station. Before it gets to the fuel rail, it has been filtered by a sock in the tank and a filter under the car. So why do fuel injectors still become clogged or have spray pattern problems? The answer involves a little bit of chemistry and a lot of heat.

Bosch K-Jetronic Fuel Injection System Service

In the 1970s, fuel injection systems were analog. At the start of the decade, you could find the Bosch D-Jetronic on many Volvos and VWs. This common rail system ran at constant pressure and the injector pulse duration was changed according to intake vacuum, barometric pressure and engine temperature. D-Jetronic did not have oxygen sensors or close-loop operation.

Turbocharger Tech Tips

In the past decade, turbochargers were installed on more cars and trucks than ever before. These are the top OEM and aftermarket tips to help you install a new turbocharger without a comeback.

Oxygen Sensor Replacement

Did you know replacing worn or failed oxygen sensors is the best way to protect expensive three-way catalysts and catalytic converters? Failure to replace failed oxygen sensors at the earliest sign of a problem, usually indicated by an illuminated check engine light, can cause premature failure of these parts.

Oxygen sensor
Belt Inspection Checklist

You might have only one chance to sell a customer a new serpentine belt. With belts lasting roughly 90,000 miles, proper inspection at the time of failure is critical not only for selling the belt, but also for ensuring add-on sales and better customer satisfaction. These are the steps you should be performing on every car or truck that enters your shop.

Direct Injection And Carbon Deposits

In 1985, Saab began using the new Bosch LH fuel injection system, and Volvo and other carmakers followed suit. The system worked such that incoming air passed through an airflow meter that sent a signal to the engine ECU telling it how much air was going into the engine. The coolant temp sensor then told the ECU how cold or warm the ­engine was, and it opened and closed the injectors when needed.

Better Diagnostics: Using Your Brain Effectively

Did you know that when you stop learning new things you also forget the things you already knew? This chilling fact is an area of great concern for the technician population, which is getting a little older on average each year. I have personally witnessed excellent diagnostic technicians who have decided that they already know everything they need to know and begin to lose their “diagnostic processes” as new technologies enter their bays.

Honda Tech Tip: Possible Modification To Front Timing Cover

Particular V6 applications described in Honda Bulletin 08-082 may require a small modification to the front timing cover during replacement of the accessory drive belt tensioner. The OE now provides an updated tensioner assembly which may cause interference with the front timing cover of some applications. Gates also offers the same updated design as the OEs.

honda tech tip
Shop Owner Or Bartender?

I sipped down the rest of my coffee and finished up the morning paperwork, then it occurred to me that the whole time I was on the phone, I wasn’t just a mechanic answering a customer’s concerns; I had taken on the role of the corner tavern bartender.

Keep Politics Out Of Your Shop

I worked for a shop owner who once told me that there were three things I could not discuss at work with co-workers or customers: sex, religion and politics. It was a simple rule to preserve civility, and one that I wish more people would observe this time of year.