Are the fuel pump returns from your shop going up? Understanding the root cause of technician errors is the first step to successfully managing fuel system parts purchases and returns.

Over the years, vehicle fuel systems have become more complex as OEs look to improve fuel burning and engine efficiency. And during that time, industry parts suppliers have noted that too many technicians are returning brand-new fuel pumps as defective, only to later discover that the root cause of the problem was a bad crankshaft sensor or fuel pump relay. As a technician, it's important that you keep up with modern fuel system technology. So in order to avoid some of the most common technician mistakes in fuel system diagnosis, let's look at how some of today's most common fuel systems operate, and what some of the common failures and "silver bullet fixes" may be.

Inaccurate Level Readings
A vehicle's fuel level must be accurately measured by the PCM in order to detect evaporative leaks. Consequently, newer fuel gauge configurations often incorporate a small module that may require as much as 20 minutes to compute the actual fuel level in the fuel tank. Without this particular bit of knowledge, many amateur mechanics may assume that a tank is half-full of fuel when, in fact, it is not.

In addition, a fuel pump inlet strainer may be installed so that it interferes with the travel on the fuel level sensor's float arm and causes an ...