Where can I find the fuel pump code?
The codes may either be directly related to the fuel pump or make reference to an air/fuel ratio problem. A scan tool or a simple code reader can be used to retrieve the information. Many auto parts stores will pull codes for free. Plus, there are inexpensive code reading tools and apps for your smartphone.
Can a false rich code be used on fuel trim?
If you use only the false rich codes to diagnose and don’t observe all the fuel trim and o2 sensor data, you may make a false diagnosis. Also, each bank has it’s own fuel trim reading. If your engine is a 4 cylinder, then it has only one bank, Bank 1.
What should my fuel trim reading be on my car?
Check fuel trim with a scan tool: This test only applies if the engine is running. All scan tools (not code readers; there’s a difference) will display a data parameter called short term fuel trim (STFT). As a general rule of thumb, fuel trim readings should be between -10 and 10, though some vehicles are different.
What does short term fuel trim ( STFT ) mean?
Short term fuel trim (STFT) Once the front oxygen sensor is warmed up after a cold start, the engine computer (PCM) starts cycling the air/fuel ratio between a little lean and a little rich. This cycling happens around once or twice per second. This air/fuel ratio adjustment is called short term fuel trim (STFT).
What are the fault codes for fuel trim?
Fig. 1 above shows the fuel trim data collected on a vehicle with the Check Engine light on and fault codes P0171 (Bank 1 System Lean) and P0174 (Bank 2 System Lean) present.
How is fuel trim data used in diagnostics?
Fuel Trim Data: A Powerful Diagnostic Tool. Once again, the fuel trim data from Fig. 1 shows a significant adjustment in all operating ranges, which leaves us with the MAF sensor. The MAF sensor communicates the volume of air entering the engine, which is used by the PCM to determine the correct injector pulse width.
Short term fuel trim (STFT) Once the front oxygen sensor is warmed up after a cold start, the engine computer (PCM) starts cycling the air/fuel ratio between a little lean and a little rich. This cycling happens around once or twice per second. This air/fuel ratio adjustment is called short term fuel trim (STFT).
Which is the correct formula for fuel trim?
The formula for fuel trim calculation is: Fuel mass = Air mass x (short-term fuel trim x long-term fuel trim) divided by (equivalence ratio x 14.64) Understanding these terms and their relationship will help you understand how to use fuel trim data shown on a scan tool.