The vehicle being tested is a 1999 Chevy Suburban with no fuel pressure. This truck had a new fuel pump installed and still did not have fuel pressure. In this video I will show you how to troubleshoot this entire fuel pump electrical system, including the fuel pump relay, wiring and computer.

Engine Performance Diagnostics chapter 3 page 26

symptoms 50

  • no start with good spark
  • no fuel pressure
  • no trouble codes

fix 50

  • repair wiring to the fuel (new pump was wired backwards)

test shown enh 50

  • how to test a fuel pump relay in a power distribution box.
  • power side switched circuit design description and operation.
  • fuel pump power and ground testing.
  • how to test a fuel pump relay
  • relay pins (what each one does and how to test them)
  • how to verify computer control of the fuel pump relay
  • bias voltage (what is it, how to use it, how it can cause misdiagnosis when using a voltmeter)
  • wiring diagram review of a fuel pump relay circuit in my classroom (a ScannerDanner premium segment)
  • how to measure fuel pump current
  • what sets a fuel pump relay control trouble code

Tools used

  • digital multimeter
  • incandescent test light
  • backprobing pins

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(Chapters 14, 15,16) Fuel Delivery and Fuel Pressure Testing

Related videos:

Fuel Pump Electrical Circuits Description and Operation:


Fuel Pump Relay Problem :


How to test and fix a PGM-FI main relay on a Honda, Acura:


How to test an electric fuel pump (1997 4.3L Chevy Blazer CPI) :


Fuel pump electrical circuit diagnosis (no fuel pressure testing) GM:


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For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available as an eBook or paper book.

Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium. There is a 14 day free trial.

On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!