Quick Jump Menu
Info Ask a Question
Advanced Search Search the Knowledgebase
Fuel Flow Sensor Common Problems (Plastic Model)
Author: Matt Liknaitzky Reference Number: AA-00217 Views: 19731 Created: 2012-06-27 19:36 Last Updated: 2012-07-04 09:56 0 Rating/ Voters


The most common problems with the plastic fuel flow sensor not giving a reading (or given a low reading) are:

Restrictor jet not installed correctly: The small restrictor jet is included with the flow sensor and needs to be installed in engines with fuel flow rates below approx. 10 gph (there are 4 jets - more on them in this article). This jet needs to be pressed into the intake port of the flow sensor with the back of a drill bit or similar, until it comes to a clear stop. At this point the nipple of the jet will be protruding slightly into the flow chamber, as a reference. The most common error here is that the jet is not installed all the way, because it can be a little difficult to press in. It requires strong steady force. When it is not pressed in all the way there is not enough fuel pressure to spin the impeller sufficiently and the fuel simple flows around the impeller.

Bubble in the chamber: The flow sensor should be installed facing slightly upwards (45 degrees recommended) so that any bubbles that collect flow through the system. If there is a bubble in the system, run the engine at high RPM until it clears. Note that if the sensor is not protected from vibration, bubbles are more likely to collect. Rubber stand-offs should be used to mount the sensor.


IMPORTANT NOTICE: You must make your own determination if the products sold by MGL Avionics are safe and effective for your intended applications. MGL Avionics makes no representations or warranties as to either the suitability of any of the products we sell as to your particular application or the compatibility of any of the products we sell with other products you may buy from us or anywhere else, and we disclaim any warranties or representations that may otherwise arise by law. Also, we offer no specific advice on how to install any of the products we sell other than passing along anything that may have been provided to us by the manufacturer or other users. If you are in need of further information or guidance, please turn to the manufacturer, FAA Advisory Circulars and guidance materials, the Experimental Aircraft Association, or other reputable sources.