Bob Howlett, Author at Tomorrows Technician
~
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.

Audi Fuel System Diagnostics

When a 2009 Audi A4 was towed in the other day, and Code P0087/16471 “Fuel System Rail Pressure Too Low” was found stored in the ECM, it was way too easy for my tech to say, “I bet it needs a new high-pressure pump.” If I were a betting man, he would have lost. It seems that nine times out of 10, it does need a high-pressure pump, but there are other problems that will set that code.

Audi Direct-Injection Issues & Carbon Deposits

In 2006, we saw the first of the direct-injection cars. VW and Audi located the injectors directly into the combustion chambers for greater efficiency. By this time, we had been seeing variable valve timing for at least six years, and there were a few cars that had variable intake runners. The new A4s and Passats had both and, in addition to the in-tank fuel pump, they had a cam-driven, ­mechanical high-pressure fuel pump that ran the fuel pressure as high as 120 bar. They are great cars, but began to exhibit a few problems that we started to see after a few years.

Volvo AWD With Active On Demand Coupling

Volvo came out with its all-wheel drive (AWD) ­vehicle in 1997. It worked pretty well, but if you didn’t ­rotate your tires and ­decided to ­install just two new tires, the size ­difference between the new tires and old tires was enough to chew up the differential. It was recommended that if you had a tire ­problem and needed just one tire, that you ­replace them all.

Front and Rear Spring Replacement

Springs and struts are prone to a few suspension issues, especially in harsher northern ­climates. The front strut bearings can start creaking, and then bind up, and we’ve seen more than a few front and rear coil springs break due to corrosion. So, let’s discuss what you can look for when you encounter one of