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  #21  
Old 07-10-2018, 02:39 PM
dick seiders dick seiders is offline
 
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Joe, I appreciate your input. I suspect my problem is knowing what is happening to fuel psi on takeoff unnerves me a bit. I will try a bit more
Of the trials.
Thanks
Dick Seiders
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  #22  
Old 10-14-2018, 08:06 PM
dick seiders dick seiders is offline
 
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Bled fuel line to sensor and went flying trying trying
To ignore alerts. Pressure drops to 1 or so on climb out, and comes up to 4 when I drop nose. Flew that way for weeks.
Ok it’s back. Pressure went to zero on climb and climbed to1.5 on level so bright it down and rebled “.Preemsure holding at 4.3 on wot run up. Now hav zero flow rate. What is going on ?
Dick Seiders
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  #23  
Old 10-14-2018, 09:43 PM
ben barron ben barron is offline
 
Join Date: Sep 2013
Location: Fall City, WA
Posts: 111
Default Low fuel pressure today too

I have had issues in the past. I’ve replaced the mechanical pump and sensor. All seemed to be working great for the last 50 hours until today when she screamed in my ear “low fuel pressure” during climb out. Got down to 2 psi for 17 seconds, below 3 for 58 seconds (data log and Savvy are great).
Landed, dropped off my wife ( who handled it well but was not interested in flying any more today) and did several ground runs to try and recreate the issue..nada..took off for a close to home test flight and all is well...very disconcerting but the ROTAX has never skipped a beat..still looking for that solid solution too.

Has anyone out there changed to the bigger fuel pump? What pressures are you seeing?
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  #24  
Old 10-15-2018, 10:21 AM
dick seiders dick seiders is offline
 
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Posts: 905
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Thanks B2.
I am thinking of both fuel pump and floss an. Mostly floscan as that is a new issue. In addition if flows an had debris that could slow its fuel flow rate that could explain low fuel pressure in that a blockage even partial coild impede flow rate to engine pump and reduce pressure to sensor. Fuel flow rate of zero is either indicating some blockage or defective reporting of fuel pressure. I am thinking of looking at floscan fist and 3 year old engine pump is
next.
Any thoughts are appreciated
Dick Seiders
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  #25  
Old 10-15-2018, 01:09 PM
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tomkk tomkk is offline
 
Join Date: Apr 2014
Location: Port Orange, Fl
Posts: 796
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Not sure a bad Floscan would create a low fuel pressure symptom. I had a low fuel pressure problem some time ago and, in my case, it was a bad fuel pressure sensor.

You might check the fuel hose between the spider on top of the engine to the fuel pressure sensor. I seem to remember reading that line can mess up fuel pressure readings if it's not purged regularly (should be done as part of the Condition Inspection).

None of that explains the zero fuel flow though. As far as I know, assuming the engine is still running, that has to be the Floscan.
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Port Orange, Fl
RV-12 N121TK ELSA #120845; first flight 06/10/2015
RV-12 N918EN ELSA #120995 Eagles Nest Project
SPA Panther N26TK in progress
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  #26  
Old 10-15-2018, 07:47 PM
Azjulian Azjulian is offline
 
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Location: Scottsdale, Arizona
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before you do anymore swapping out you really need to put a mechanical pressure gauge on there to validate what you are seeing from the digital.

On the Rv12 a friend asked me to look at they had swapped several components like you, I took the AN adapter off the mechanical pump and that was blocked with plastic residue on the outlet side, have no clue where that came from.
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  #27  
Old 10-15-2018, 09:53 PM
dick seiders dick seiders is offline
 
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Tom, thanks for the thoughts. I did bleed the sensor line twice on Sat. It
Was following that the flow rate dropped to zero.
Azijulian I will try a mechanical gauge to confirm sensor readings before taking out the floscan. Thanks
Dickseiders
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  #28  
Old 10-16-2018, 08:14 AM
Mich48041 Mich48041 is offline
 
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Location: Riley TWP MI
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Bleeding the fuel pressure line does no good whatsoever unless the line is plugged and debris needs to be flushed out. It doesn't matter if the line is full of air. The air will be at the same pressure as the fuel and exert the same pressure against the fuel sender diaphragm. The air will eventually be absorbed into the fuel. I have never purged my fuel pressure line. I have been lucky in that my sender has not failed . . . yet.
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  #29  
Old 10-16-2018, 11:05 AM
dick seiders dick seiders is offline
 
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Joe, you are fortunate that you have experienced no problems with the fuel pressure issue. I have replaced the VDO twice. On the bleed issue my fp went from 1.5 to 4.3 # after bleeding line
to sensor.
Still uncertain about fp and now have transducer problem as well.
Dick Seiders
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  #30  
Old 10-16-2018, 11:42 AM
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tomkk tomkk is offline
 
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Quote:
Originally Posted by Mich48041 View Post
Bleeding the fuel pressure line does no good whatsoever unless the line is plugged and debris needs to be flushed out. It doesn't matter if the line is full of air. The air will be at the same pressure as the fuel and exert the same pressure against the fuel sender diaphragm. The air will eventually be absorbed into the fuel. I have never purged my fuel pressure line. I have been lucky in that my sender has not failed . . . yet.
The MM indicates flushing the fuel pressure hose at Annual or 100 hrs.

I read about the rationale some time ago but can't to find it now. I think it had something to do with the fuel pressure sensor being below the spider but don't recall the symptoms it caused.
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RV-12 N121TK ELSA #120845; first flight 06/10/2015
RV-12 N918EN ELSA #120995 Eagles Nest Project
SPA Panther N26TK in progress
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