Shade Tree Method for Diagnosing a Fuel Pump

!!Warning!! Please read entire description for safety info!

In this video I'll show you an old trick to help you diagnose a faulty fuel pump. This trick is nothing new and was shown to me by some old timers that have been around the block a time or two. Over the years I've had the opportunity to use this to help me diagnose faulty fuel pumps on many occasions.

How it works: On the vehicle shown in the video the fuel pump was frozen because the brushes in the fuel pump where not able to make good electrical contact with the motor. The motor had a "bad spot" on it, or a spot that has high resistance on it. Knocking on the fuel tank will jar the fuel pump just enough to get the fuel pump brushes to make contact with a better spot on the motor. Once the contact has been made then the motor will then begin to operate as designed and create fuel pressure.

Note: Just because the fuel pump works after performing this does not mean your vehicle is fixed. This problem is likely to occur again. Fuel pump replacement is likely the solution. Also, as state in the video, I don't really think this test can really take the place of an appropriate fuel pump diagnosis. (Appropriate fuel pump diagnosis not shown or described here). In some cases this test can be misleading as knocking on the fuel tank could not only jar a frozen fuel pump into working again, but it could also jar a poor electrical connection (not inside the fuel pump) just enough to where fuel pump function is restored.

Also note: There are three ingredients needed for an engine to run, Fuel, Spark, and Compression. If any one of these ingredients are missing then you will get a "crank not start" much like the one shown in the video. You should confirm that no fuel pressure is present, using proper procedures outlined in your repair manual, before trying this.

Guys, this is some good information. But, I don't make any guarantees that by using this information you will make a proper diagnosis of your vehicles problem. There are just too may variables involved in a "crank no start" for me to go over in this video and this description. Take the information given with a grain of salt.

Warning! If you do this procedure be sure that the vehicle is in park, the parking brake is applied securely, and that the person inside the vehicle doing the cranking has his or her foot on the brake to prevent the vehicle from rolling. This procedure involves an individual going under the vehicle while it is being cranked. If the vehicle where to roll while you are under the vehicle it could result in serious injury or death!!

DISCLAIMER
Barbour's Auto Help is not responsible for any damage or personal injury incurred in the process of performing any auto repairs done by you the viewer. Automotive repair is extremely dangerous. Repair your vehicle at your own risk. It is the viewers responsibility to verify all information and procedures as outlined in YOUR REPAIR MANUAL AND OWNERS MANUAL FOR YOUR VEHICLE. Owning and using a repair manual suited for your vehicle is essential for correctly and safely performing ANY repair to your vehicle. Always wear safety glasses and heed all instructions for use applicable to any piece of equipment you may use. Due to circumstances out of the control of Barbours Auto Help, Barbours Auto Help makes no guaranty that by the use of the information given in this video a quality repair will be made. Barbour'sAutoHelp makes no guaranty that the information provided is totally complete, syncronized and accurate. Verify everything using an appropriate repair manual. You can do it. Do it right and do it safely.

Repair your vehicle at your own risk! Barbour's auto help does not guaranty a proper repair using these techniques.

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Music by:
Zombie Rock by Audionautix is licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/by/4.0/)
Artist: http://audionautix.com