How to quickly identify a vacuum leak using fuel trim and water:

1998 Chevy Van 5.7 No Crank and Misfire Troubleshooting:

1998 Chevy 5.7 Misfire (secondary ign-injector balance-psi transducer testing):

end faq

1998 Chevy 5.7 misfire (P0300) and fuel system too lean (P0171 and P0174) trouble codes AFTER the intake manifold was removed. This is the same van that I shot two different videos on, one for each of my channels.

In this third installment, I was called back to the shop after they repaired the injector problems for the two cylinder misfire.

Engine Performance Diagnostics Chapter 1

Topics discussed

symptoms

  • popping/backfiring through the intake
  • hesitation
  • poor idle/stalling
  • misfire

fix

  • replace o-ring around the fuel injector assembly in the upper intake manifold

test shown

  • how to use fuel trim to identify a vacuum leak
  • how to locate a vacuum leak with water

Tools used

end faq

Playlist

(Chapter 1) Misfire ID, Compression Tests, Vacuum Leaks, Fuel Trim, Head Gasket, Restricted Exhaust, Low Power, DMM

Related videos:

Understanding Short Term and Long Term Fuel Trim (an SD Premium video):

Causes of lean condition trouble codes P0171, P0174 - GM 5 3L:

ow to use Fuel Trim to identify the cause of a P0171 and P0174 code:

end faq


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!

 

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0 #1 Powerplus 2018-07-21 09:20
Why was air mix 14.7?