HarleyTechTalk

Dyno & Tuning Zone => AFR & Tuning Zone => Topic started by: jjdalynh on May 10, 2019, 04:17:07 AM

Title: Dynojet Harley Fuel Tap readings
Post by: jjdalynh on May 10, 2019, 04:17:07 AM
 :scratch:
either the pressure transducer on my fuel tap is broken or i don't understand the spec....  with the tap disconnected from the bike, it should read atmospheric pressure, right?   14.7(at sea level) and the transducer reading the difference between atmo and input pressure should give a 0 difference.  0 difference for the transducer corresponds to .5V?

the output i'm getting in raw volts is 0. 
Title: Re: Dynojet Harley Fuel Tap readings
Post by: rigidthumper on May 10, 2019, 04:59:31 AM
The transducer is designed to read diaphragm movement- if there is no fuel pressure, there is no diaphragm movement.
Title: Re: Dynojet Harley Fuel Tap readings
Post by: jjdalynh on May 10, 2019, 05:12:22 PM
from what I can tell, 0psi should read .5V, 100ps should read 4.5.  I've got 0V.  methinks my transducer is broken.
Title: Re: Dynojet Harley Fuel Tap readings
Post by: rigidthumper on May 11, 2019, 05:57:03 AM
Verify 5V reference is getting to the sensor, and that the ground is good as well.
Title: Re: Dynojet Harley Fuel Tap readings
Post by: jjdalynh on May 11, 2019, 06:26:13 AM
yup, first thing i did.  5V measured at pins when disconnected, 4.75V (within spec) backprobed while plugged in.  new sensor on its way anyways. 
Title: Re: Dynojet Harley Fuel Tap readings
Post by: jjdalynh on May 29, 2019, 04:53:53 AM
bad transducer.  new one from onlinecomponents.com and it's all good now, 59.x psi all around