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VM1000 low pressure fuel sender question

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Vanremog(at)aol.com
Guest

Posted: Sat Jun 30, 2007 7:01 pm Post subject: VM1000 low pressure fuel sender question

I have had an ongoing issue with my Vision Micro Systems VM1000 (original  circa 1996) fuel pressure sender sensing off the output of my  stock mechanical pump.  Since day one it has always indicated high within  the low pressure range (I am carbureted).  I typically see from 5 to 9 psi  indicated (lower at higher altitude) and it does respond properly by increasing  about 1-2 psi when I turn on the boost pump.  It correctly reads zero  when the a/c is not running and the boost pump running on the ground without the  engine running produces the same high reading result.  When it reads above  8 psi, the display blinks normally to alert me.  I suspect the  sender has always been just off calibration but would like to see if  changing the sender will solve the problem.

  

 Does anyone have a spare VMS low pressure fuel sender laying around that  they would be willing to loan or sell before I call VMS?

  

 -Thx

  

  

  

 GV (RV-6A N1GV O-360-A1A, C/S, Flying 857hrs, Silicon Valley,  CA)





See what's free at AOL.com. 

  [quote][b]

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daubuchon(at)volcano.net
Guest

Posted: Sat Jun 30, 2007 7:38 pm Post subject: VM1000 low pressure fuel sender question

Hey Gary,,

Fyi,,



From day one,, (circa 2000), the fuel flow in my RV4 always read on the high side.  Added to that, a rather large in-flight fluctuation that I always assumed was due to the fact that I could not get the required straight run due to the relatively small size of the firewall on the 4.



I those "early days," Vision Micro did not have a user-changeable "K factor" to adjust for installation errors and/or differences.



A few years ago, the fuel flow transducer began to show signs of "morning sickness," in that at startup, there would be a considerable delay before the fuel flow registered anything, then it would suddenly kick-in, as if the impeller was jammed.



In the mean time, Vision Micro finally revised the eprom and provided a very simple means to input a "K-factor."



So, a few years ago I replaced the transducer and the eprom,,

And ever since I am happy to report that my fill-ups always agree with the fuel-burned totals to within less than two tenths, and usually +- .1.



Additionally, the in-flight fluctuations were dampened dramatically.



Moral of the story, I had a bad transducer out of the box from day one,,,

And the programmable k-factor was like manna from heaven! 



Derrick

On Jun 30, 2007, at 7:59 PM, Vanremog(at)aol.com (Vanremog(at)aol.com) wrote:

 	  Quote: 	
		    I have had an ongoing issue with my Vision Micro Systems VM1000 (original circa 1996) fuel pressure sender sensing off the output of my stock mechanical pump.  Since day one it has always indicated high within the low pressure range (I am carbureted).  I typically see from 5 to 9 psi indicated (lower at higher altitude) and it does respond properly by increasing about 1-2 psi when I turn on the boost pump.  It correctly reads zero when the a/c is not running and the boost pump running on the ground without the engine running produces the same high reading result.  When it reads above 8 psi, the display blinks normally to alert me.  I suspect the sender has always been just off calibration but would like to see if changing the sender will solve the problem.

  

 Does anyone have a spare VMS low pressure fuel sender laying around that they would be willing to loan or sell before I call VMS?

  

 -Thx

  

  

  

 GV (RV-6A N1GV O-360-A1A, C/S, Flying 857hrs, Silicon Valley, CA)





See what's free at AOL.com. 

  	  Quote: 	
		  

href="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/Navigator?RV-List

href="http://forums.matronics.com">http://forums.matronics.com



	
	




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Vanremog(at)aol.com
Guest

Posted: Sat Jun 30, 2007 10:38 pm Post subject: VM1000 low pressure fuel sender question

In a message dated 6/30/2007 8:40:42 P.M. Pacific Daylight Time,  daubuchon(at)volcano.net writes:

  	  Quote: 	
		     From day one,, (circa 2000), the fuel flow in my RV4 always read on the    high side.  Added to that, a rather large in-flight fluctuation that I    always assumed was due to the fact that I could not get the required straight    run due to the relatively small size of the firewall on the  4.

	


 

 ========================================

  

 Derrick-

  

 Yes I had a problem early on with my fuel flow too but that  factory change fixed mine.  But it's the fuel pressure that  bugs me now.  How well does your FP work?  You're carbureted,  right?

  

  

  

 GV (RV-6A N1GV O-360-A1A, C/S, Flying 859hrs, Silicon Valley,  CA)





See what's free at AOL.com. 

  [quote][b]

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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daubuchon(at)volcano.net
Guest

Posted: Sun Jul 01, 2007 3:15 am Post subject: VM1000 low pressure fuel sender question

Gary,,

Yes, I am normally aspirated.  (I never pass up an opportunity to use that phrase!)

And I apologize, until your reply, I was thinking flow not pressure,, sorry to belabor the list with a reply that had no bearing on the subject matter.



As to my fuel pressure,, it has always seemed to be in the ballpark.  No complaints.



Derrick

On Jun 30, 2007, at 11:36 PM, Vanremog(at)aol.com (Vanremog(at)aol.com) wrote:

 	  Quote: 	
		     In a message dated 6/30/2007 8:40:42 P.M. Pacific Daylight Time, daubuchon(at)volcano.net (daubuchon(at)volcano.net) writes:

  	  Quote: 	
		    From day one,, (circa 2000), the fuel flow in my RV4 always read on the   high side.  Added to that, a rather large in-flight fluctuation that I   always assumed was due to the fact that I could not get the required straight   run due to the relatively small size of the firewall on the 4.

	


 

 ========================================

  

 Derrick-

  

 Yes I had a problem early on with my fuel flow too but that factory change fixed mine.  But it's the fuel pressure that bugs me now.  How well does your FP work?  You're carbureted, right?

  

  

  

 GV (RV-6A N1GV O-360-A1A, C/S, Flying 859hrs, Silicon Valley, CA)





See what's free at AOL.com. 

  	  Quote: 	
		  

href="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/Navigator?RV-List

href="http://forums.matronics.com">http://forums.matronics.com



	
	




 [quote][b]

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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n616tb(at)btsapps.com
Guest

Posted: Sun Jul 01, 2007 11:20 am Post subject: VM1000 low pressure fuel sender question

Hi Gary,      

   

 	  Quote: 	
		  >before I call VMS?<<  

    
	


   

[Tim] Let me know how that works out.  I had a little help to finally get my issue with them resolved, but VM is pretty non responsive.  

Do Not Archive  

   

  

  

       [quote][b]

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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