VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #51  
Old 02-12-2018, 09:50 AM
jonweisw jonweisw is offline
 
Join Date: Mar 2005
Posts: 95
Default Fuel Pump Autopsy

I cant say I found anything outwardly wrong with it and given the intermittent nature of the problem, I am not surprised. Nor would I ever profess to have ANY idea of what I was looking for other than something obvious.

More hours on the new pump with the same observation; the pressure is a steady 10psi above where it was before the swap without any wavering.

Here are pictures of the inside of the fuel pump.










Last edited by jonweisw : 02-12-2018 at 11:21 AM.
Reply With Quote
  #52  
Old 02-12-2018, 09:53 AM
jonweisw jonweisw is offline
 
Join Date: Mar 2005
Posts: 95
Default Autopsy 2

More pictures...











Reply With Quote
  #53  
Old 02-12-2018, 11:32 AM
hgerhardt's Avatar
hgerhardt hgerhardt is offline
 
Join Date: Oct 2006
Location: torrance, ca
Posts: 416
Default

Thanks for doing the autopsy! One more thing you ought to do is take apart the check valves. You'll need to grind away the stakes helping hold the valves in place. I suspect your low pressure problem is due to check valve internal leakage.

Heinrich
Reply With Quote
  #54  
Old 02-12-2018, 04:28 PM
Danny King's Avatar
Danny King Danny King is offline
 
Join Date: Dec 2004
Location: Southlake, Texas
Posts: 560
Default One data point

I read this tread with interest. My pump had 1200 hours on it when it started having fluctuations just like others observed. The pressure would start and 24 psi and drop to as low as 20 psi. I had the warning set to come on at 21 psi so it kept getting my attention!

I checked the hoses and electrical connections and all was well. Being like minded with Walt, I replaced the pump. The only difference now is the fluctuations begin at 25 psi, one psi higher than the old pump!

My guess is the new pump's additional psi is due to it having 1200 less hours on it. I was hoping you gents would have solved this mystery for me, but I guess I'll have to keep looking.

Anybody interested in a slightly used .... ERR.... well tested Lycoming fuel pump that puts out 24 psi?
__________________
Danny King
Beautiful Doll 80434 TT 1565 hours
I0360 A1B6 200 HP
Christen Inverted Oil
First Flight 12 July 2000
VAF Dues current for 2018

Last edited by Danny King : 02-12-2018 at 06:46 PM.
Reply With Quote
  #55  
Old 02-12-2018, 05:52 PM
skylor's Avatar
skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 606
Default

Quote:
Originally Posted by Danny King View Post
Anybody interested in a slightly used .... ERR.... well tested Lycoming fuel pump that puts out 24 psi?
I think the popular term for this these days is "Flight Proven"

Skylor
Reply With Quote
  #56  
Old 02-12-2018, 08:26 PM
RV7A Flyer's Avatar
RV7A Flyer RV7A Flyer is offline
 
Join Date: Jul 2013
Location: US
Posts: 1,508
Default

Quote:
Originally Posted by skylor View Post
I think the popular term for this these days is "Flight Proven"

Skylor
We call it "flight qualified"

or TRL 9.
__________________
2017 Dues paid!
Reply With Quote
  #57  
Old 02-13-2018, 12:29 PM
Captain_John's Avatar
Captain_John Captain_John is offline
 
Join Date: Jan 2005
Location: KPYM
Posts: 2,530
Default Another data point

Like Danny I was getting the fluctuations in the exact same range. I installed a Tempest pump and now see 27.7 psi or more!

I dare say that I found the smoking gun and I am thrilled with the results!

Danny, which pump did you buy? Did you get a Tempest?

Anyone interested in buying a slightly even less used pump with 700 hours on it?

CJ
__________________
RV-7 Flying - 700 Hours in 3 Years!
TMX-IO-360, G3i ignition & G3X with VP-X
Reply With Quote
  #58  
Old 02-16-2018, 03:14 PM
Danny King's Avatar
Danny King Danny King is offline
 
Join Date: Dec 2004
Location: Southlake, Texas
Posts: 560
Default

Quote:
Originally Posted by Captain_John View Post
Like Danny I was getting the fluctuations in the exact same range. I installed a Tempest pump and now see 27.7 psi or more!

I dare say that I found the smoking gun and I am thrilled with the results!

Danny, which pump did you buy? Did you get a Tempest?

Anyone interested in buying a slightly even less used pump with 700 hours on it?

CJ
I replaced the original Lycoming pump with a Tempest. Today's flight the Tempest was putting out 27 psi and only deviated lower by 3 psi. I'm happy now.
__________________
Danny King
Beautiful Doll 80434 TT 1565 hours
I0360 A1B6 200 HP
Christen Inverted Oil
First Flight 12 July 2000
VAF Dues current for 2018
Reply With Quote
  #59  
Old 02-16-2018, 03:49 PM
AlexPeterson's Avatar
AlexPeterson AlexPeterson is offline
 
Join Date: Sep 2005
Location: Maple Grove, MN
Posts: 2,040
Default

Quote:
Originally Posted by Danny King View Post
I replaced the original Lycoming pump with a Tempest. Today's flight the Tempest was putting out 27 psi and only deviated lower by 3 psi. I'm happy now.
Great - now cover up the fuel pressure gauge and don't look at it anymore! Given the number of people who've posted similar fluctuations, I'd say the fluctuations are not completely unexpected. I've had the drops into the mid or lower teens show up from time to time for 16 years, two different pumps. Engine has never coughed. Current pump is a Tempest, but it is 10 years old so I might swap it out.
__________________
Alex Peterson
RV6A N66AP 1600+ hours
Maple Grove, MN
Reply With Quote
  #60  
Old 02-16-2018, 04:31 PM
RV8JD's Avatar
RV8JD RV8JD is offline
 
Join Date: Jan 2005
Posts: 740
Default

For reference, it seems that many of our Lycomings have a minimum fuel pressure requirement of 14 psi (inlet to fuel injector).

On my previous RV-8, the fuel pressure warning was set at 16 psi. I hit that a couple of times in a long climb, but the fuel flow was fine and the engine never stumbled, but I turned on the boost pump anyway. I finally replaced the fuel pump and it fixed the issue.

Lycoming Operator's Manual:

https://www.lycoming.com/sites/defau...2060297-12.pdf
__________________
Carl N.
Arlington, WA (KAWO)
RV-8, 300 Tach Hours
(Pic 1),(Pic 2)
- Out with the Old, In with the New
(Pic)
RV-8, 1938 Tach Hours (Pic 1),(Pic 2) - Sold

Glasflügel H-201B Standard Libelle, N564NS - Sold
Rolladen-Schneider LS1-f, N61MP - No longer owned

Last edited by RV8JD : 02-16-2018 at 04:41 PM.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 11:23 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.