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Yes I agree Mark.............The ability to clear an air lock and reprime the pumps is much more important
than a potential flooding problem which is a pain in the xxzz but at least you are on the ground and is not
life threatening..............So am with you that all our flying fuel systems should incorporate the bypass as it
is a simple and proven way to make sure you can get fuel to the engine after running a tank dry !!............
Kelly Troyer
"DYKE DELTA JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold
"TURBONETICS"_TO4E50 Turbo
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Monday, July 4, 2011 5:28 AM
Subject: [FlyRotary] Re: Leaking injectors?
Kelly,
Yes, the crossover is good for handling a leaky injector, but IMHO the more important feature is to ensure that you can get a re-start if you run a tank dry. As I stated earlier, the Eggenfellner bunch had this problem and fixed it with the crossover circuit. EFI pumps aren't very good at sucking/pumping air. That's why I incorporated a crossover circuit into my fuel system. I make it a rule to never run a tank completely dry, but if it happens, I can rest assured that I can get fuel pressure restored again by switching tanks.
Mark
On Sun, Jul 3, 2011 at 10:39 PM, Kelly Troyer <keltro@att.net> wrote:
I agree Mark !!.........I never had flooding problems again after installing the by-pass on
my well worn 88 RX7.................On an auto you do not have the ability to shut down the
fuel pump as has been suggested plus as Steve noted even that was not enough to
keep an extremely worn injector from leaking enough to cause flooding.............
Thanks to all of the group that shared their ideas and "Real World Experiences"........
This is what sets this group apart from some on the net............You guys (and girls)
freely share your trials and tribulations whether successful or failures so your fellow
"Rotorheads" do not have to reinvent the wheel ...............
Kelly Troyer
"DYKE DELTA JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold
"TURBONETICS"_TO4E50 Turbo
From: Mark Steitle <msteitle@gmail.com>
Sent: Sunday, July 3, 2011 9:48 PM
Subject: [FlyRotary] Re: Leaking injectors?
...and another good argument for having a bleed-bypass circuit. ;-)
Mark
On Sun, Jul 3, 2011 at 9:13 PM, Steven W. Boese <SBoese@uwyo.edu> wrote:
My standard shutdown procedure has always been to cut the power to the fuel pumps until the engine stops and then shut down the power to the rest of the system. In early May, after sitting overnight at an airport away from home, the engine started on only one rotor and then started to run on both rotors after a few seconds. It did this twice more after being shut down at least overnight. Finally, the engine refused to start at all. Removing the spark plugs indicated a flooded condition, much more evident on rotor one than rotor two. Removing the injectors and pressurizing them on my injector test rail, the primary injector of rotor one leaked fuel at a slow drip and the secondary injector of rotor two would form a drop of fuel that would evaporate fast enough that it didn't actually drip. The other two injectors remained dry. Since all those injectors were most likely the original ones from 1986
and had well over 100,000 miles before use in the aircraft, I replaced them with new ones from RC Engineering. I haven't had flooding problems since the replacement. Apparently, there was enough fuel that could leak through the injectors and cause flooding even after the shutdown procedure that involved killing the engine by shutting off the fuel pumps. Probably, heat soaking the firewall forward fuel lines and fuel after shutdown resulted in pressure buildup and enough fuel leaking through the worn injectors to cause a problem. Just my recent experience for what it is worth.
Steve Boese
RV6A, 1986 13B NA, RD1A, EC2
I think that the idea is to shut down the pump(s) with the engine running. The injectors will continue to do their thing, & the engine quits when pressure drops too low to flow through the open injectors. Charlie On 07/03/2011 02:28 PM, Kelly Troyer wrote:
No !!...........The check valve is located in the inlet to the pump and will hold regulated pressure
indefinately or until relieved by leaky injectors or the afore mentioned bypass sysrem.........
Kelly Troyer
"DYKE DELTA JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold
"TURBONETICS"_TO4E50 Turbo
From: Ernest Christley <echristley@att.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Sunday, July 3, 2011 2:15 PM
Subject: [FlyRotary] Re: Leaking injectors?
On 07/02/2011 09:52 AM, Kelly Troyer wrote:
Ernest,
Your EFI fuel pumps have a check valve in them and will hold regulated pressure
for a long time or until leaky injectors relieve this pressure..........Short of replacing
the injectors the fix is to put a pressure relief orifice from the fuel pressure line to
the fuel return line...
Shouldn't shutting down by cutting power to the fuel pump relieve the pressure, though? |
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