A negative fuel trim is considered anything at or below the minus 10 percent threshold. Ron addresses the common issues that can cause fuel trims to go negative. Issues like leaking fuel injectors, a defective fuel pressure regulator and defective MAF sensors will be addressed.
This class is taken directly from Ron Bilyeu’s full course: The Diagnostic Approach. Scroll down to view the whole course!
The Diagnostic Approach
Successfully diagnosing a drivability issue can be as easy as understanding scan tool data, what modules relate to each other and why it’s important to retrieve codes on all modules. This course is taught by instructor and master data analyst Ron Bilyeu who will take you through a comprehensive approach to diagnosing drivability using computer data. Identify if the issue is breathing, fuel or ignition and how to diagnose using scan data for those systems. The information in this course can be applied to domestic and import applications.
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