X-CGP-ClamAV-Result: CLEAN X-VirusScanner: Niversoft's CGPClamav Helper v1.23.0 (ClamAV engine v0.103.0) X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "David Leonard wdleonard@gmail.com" Received: from mail-lf1-f44.google.com ([209.85.167.44] verified) by logan.com (CommuniGate Pro SMTP 6.3.11) with ESMTPS id 1018820 for flyrotary@lancaironline.net; Mon, 23 May 2022 16:38:10 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.167.44; envelope-from=wdleonard@gmail.com Received: by mail-lf1-f44.google.com with SMTP id y32so27542137lfa.6 for ; Mon, 23 May 2022 13:38:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=i7cnTloM5RHfcRp4LqPeCLu6R39hqiLHUR7ry1Ai04g=; b=qiKFaSXTT3GA13yRpMnZnWIZPMKLA1NTni1IgTKOFxtUs0eFXoWF0cYxHox4CpNH1F 8+1dVSUsn3P+fAIWwtz4lVWBDvjPpYAag7mXdzEvA2kGIuDpop6YGJeTDVJzjmpXmYC/ gtC+9B0mi0mSZ97Ism1yHRVq7K39xtXrAmy5sudnX48W4T0jZv2hrtEAjw5KnNujtWh3 bRAWK1XkSqbrYT+DvGx81GfbszCe774RCCbI/VbYioW5G+rWlhpmvIrlHKUTeFJ1i/Om YY4Io1wXjW/dhsqandbCiX7+2pkBPA8G8pT/KslG8KSNPyhcwoZzn9wepbd3veokvf3u 4fDQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=i7cnTloM5RHfcRp4LqPeCLu6R39hqiLHUR7ry1Ai04g=; b=ZQy/GyeR81l1IAtUBb+yD6tGcxbtWN+pAYSyDOd61r+54W2VKHCPUkgKT+3i5UgTkz 3DUBTvoAfio+T7RcncgdAlmmV04JvEWCQAQ0Z+McFnKce/etzOdCt7dF83/VYI8ioj68 rx8hiMADC86TKQExTduI4n4zIJV5XuizLo2QLeLHwULSjdWPIH8D8Awnw4vFvPwKoB6m p3e2X+8C/13LAbbhCpvSI9jjY7ghOsQuhQxRqT8QYR+yKxyMcw32kvssqINxQ41CbHXJ v0O73Ci1N2vYdgTZ3+VeYBWX4+LjaRViphkzDemyKFc5+FZRIV11OClloZJ1YTT3s5Tx sAiw== X-Gm-Message-State: AOAM530O8y7vyy5H4P794cWquXiCrcNz9MViMMkQhKwKt4yMqfAbPr5B PP+NRbza2bBxKqgB/69FcaeuMVoPlO+xMaK9XSNDKXBR X-Google-Smtp-Source: ABdhPJzNdloPSv3YgQKc0/DQTBhyWZmQHECKEcllluh9fXqDVWxtURoKWIxU52blJm67HJ/qoKqThDJXSqpdVdTKWIU= X-Received: by 2002:a05:6512:ad6:b0:478:68c8:dd73 with SMTP id n22-20020a0565120ad600b0047868c8dd73mr6715109lfu.296.1653338272675; Mon, 23 May 2022 13:37:52 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Date: Mon, 23 May 2022 13:37:41 -0700 Message-ID: Subject: Re: [FlyRotary] Re: Fuel pressure trending lower. To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="0000000000006fbcb005dfb3d076" --0000000000006fbcb005dfb3d076 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Finn, Where is your fuel filter located? Mine in downstream of the pump, but before the fuel injectors. Fuel pressure gauge is just upstream of the filter for me, which I now realize is sub optimal but does provide good info about the state of the fuel filter. The pressure starts going up as the filter clogs. I also have a fuel flow sensor on my return fuel line, which has turned out to be a great troubleshooting tool and reflects the overall health of the fuel system. I am using the walbro pumps that Tracy recommended. I bought 10 of them once to have a supply on hand because I never again want to delay replacing them when I see the performance start to degrade. For me, the first sign would be decreasing return flow. It more or less seems to linearly decrease with the total time on the pump. For me, the pressure starts dropping as the return flow gets closer to zero. I have taken to replacing the pump earlier in the process, like 50% reduction in return flow. With pumps like the walbro, current demand to the pumps goes up as the flow goes down. At some point the current demand will blow the breaker and terminate the flight. I would guess that fuel pumps seem to last 400 hrs or so. This is an improvement since I installed a larger fuel filter to keep down the pressure differential. If your pumps are similar and your fuel pressure is dropping at the injector, and the problem is not a clogging fuel filter, then I suggest you replace the pump ASAP. They seem fairly susceptible to damage from particulate contamination or being run while dry. Cheers, Dave Leonard On Mon, May 23, 2022 at 9:04 AM Steven W. Boese SBoese@uwyo.edu < flyrotary@lancaironline.net> wrote: > Finn, > > What the fuel pump should be flowing and what it is flowing may be two > different things and needs to be evaluated before being "comfortable". > That is why I would encourage you to measure the actual flow rate if you > can do it safely. When I left MS71 in May of 2017 following Charlie's > rotary fly-in, my 13B burned 18 gal/hr on take-off and initial climb at > 5800 RPM and initial OAT of 80 degrees F. Your set-up likely would requi= re > this much or more. This was the indication from a Flowscan turbine type > sensor which has been demonstrated to be accurate. The flow measurement > would just be a next step in the investigation. If the flow rate is not > what is what it should be, then determining why would follow. The > replacement pump should be helpful in this regard. > > If you recover the fuel being bypassed by the regulator, bubbles in that > fuel will not necessarily indicate air leaking into the fuel drawn into t= he > pump. The process of dropping the pressure when the returned fuel passes > through the regulator, causes dissolved air in the fuel to separate. > Bubbles in this flow will be obvious. If fuel is drawn from a small > reservoir (< a gallon or so) and returned to that same reservoir where th= e > bubbles are allowed to escape to the surface, the bubbles will eventually > disappear as the fuel is degassed. Degassing all the fuel from the wing > tank is unlikely to occur due to the large volume of fuel and the large > surface area of the fuel in the tank. This is why returning bypassed fue= l > directly to the fuel pump intake or to a small unvented header tank (wher= e > the separated air is allowed to accumulate) may not be the best practice. > > FWIW > > Steve Boese > > > > > ------------------------------ > *From:* Rotary motors in aircraft on behalf > of Finn Lassen finn.lassen@verizon.net > *Sent:* Monday, May 23, 2022 6:25 AM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: Fuel pressure trending lower. > > https://vansairforce.net/community/showthread.php?t=3D168793 > > The GSL414 should be flowing more than 30 GPH at 40 psi. More than double > of what I need. Does that qualify as "a comfortable amount"? > > I have a new one on order. I'll try to hook up my own test. > > Finn > > On 5/22/2022 11:00 PM, Sboese sboese@uwyo.edu wrote: > > Finn, > > It seems to me that the problem you=E2=80=99re seeing is consistent with = the > capacity of the pump not being sufficient for the max flow required by th= e > engine and the pump flow capacity is decreasing with use. You appear to > have checked everything but the flow capacity of the pump under normal > system pressure which is what you really need to know. If you can divert > the returning fuel flow from the pressure regulator to a measuring vessel > and and collect that fuel for an accurately measured time, the pump flow > rate can be calculated. This flow rate should be greater than the maximu= m > required by the engine by a comfortable amount. > > My apologies in advance if this is obvious. > > Steve Boese > > On May 22, 2022, at 8:05 PM, Stephen Izett stephen.izett@gmail.com > wrote: > > =EF=BB=BF > > =E2=97=86 This message was sent from a non-UWYO address. Please exercise = caution > when clicking links or opening attachments from external sources. > > Hi Finn > > Thanks for the reminder of my pump issue. > Yes, you chose more wisely the pump capacity. Mine were way overkill. > > So I=E2=80=99m thinking options are: > 1. Fuel Pressure transducer fault - No - as this was confirmed by the > mixture monitor and tune going out. > 2. Power supply to pump via fault in termination or switch current path - > Unlikely, given the slow reduction - I would imagine a faulty connection > would create a less uniform symptom. > 3. Alternator Battery voltage/current reduction over time - No - You woul= d > see this in the log. > 4. Significant Fuel leak - No - Would think this would have become obviou= s > on inspection and not intermittent. > 5. Fuel Regulator - They are pretty simple but unsure if they can fail > with this symptom? > 6. Fuel filter blockage - Certainly this would have to be an obvious, but > I take it you swapped this out. > 7. Pump internal failure - > Electrical - ? > Mechanical breakage - ? > Flow Path - blockage - unlikely if filtered effectively > > Where is your pressure transducer in relation to Reg/Any post pump > filtering/Flow Transducer/Rail? > > If fuel regulator and filters can be discounted, I=E2=80=99m struggling t= o trust > the pump. But your test had it sounding in good shape and to spec. > > So frustrating. > > Cheers > > Steve > > > > > > On 23 May 2022, at 8:44 am, Finn Lassen finn.lassen@verizon.net < > flyrotary@lancaironline.net> wrote: > > Thanks Steve. > > >From your March/April 2017 posts it was a GSL392 that failed (high > current draw/low pressure, even after you removed the insect you found in > the inlet). > > So this afternoon I ran the pump for about an hour. Amp draw from 3.04 to > 286 depending on voltage. Pressure between 43 and 40 psi (also depending = on > voltage). No noticeable degradation. Of course the difference with this > test is that no fuel went to engine -- all recirculated through pressure > regulator and back to tank. But no signs of a failing pump in terms of > higher current draw and less pressure. > > I guess I should put a temp probe on the pump and see what it reads durin= g > flight to see if that could be a factor. > > Finn > > On 5/21/2022 9:01 PM, Stephen Izett stephen.izett@gmail.com wrote: > > Hi Finn > > I had from memory a 393 fail. Can=E2=80=99t recall the symptoms sorry. > > I test before takeoff and then run both pumps below 2ooo ft incase of > failure. > I plan to instal a comparator relay board in fuel pressure circuit to > automatically bring on backup pump and failure indicator. > So testing before flight becomes - switch off and back on main engine > pump. This will save amps and wear of backup pump. > When I switch off a pump at WOT the engine dies pretty much > instantaneously and don't want to be fiddling with a restart in the Glasa= ir > which glides like a brick with the gear out in the breeze. > > Regards > Steve Izett > > > > > > On 21 May 2022, at 10:30 pm, Finn Lassen finn.lassen@verizon.net < > flyrotary@lancaironline.net> wrote: > > Recently I noticed my fuel pressure being low. Noticed because engine did > not come up in power when advancing to full throttle. Noticed mixture rea= l > lean. Checking fuel pressure as low as 28 psi (normally 35 and up to 40 a= t > full throttle). > > Going over my engine logs since first flight I now see that fuel pressure > has been trending lower through each flight -- more pronounced on longer > flights (40+ minutes). More and more pronounced over the months and becam= e > really noticeable over last month. Could explain why mixture tuning > *appeared* to have changed. Nice to have engine logs from practically > each flight. > > But why? Pump getting weaker? > > My primary fuel pump is a GSL414. I figured it was wasted energy to push > way more fuel than needed through the pressure regulator back to the tank= . > > My secondary (backup) pump is a GSL393. When turning that on, fuel > pressure comes back up to where it needs to be. > > Anyone have experience with failing or weak EFI pumps, particularly the > GSL414? > > Finn > > > > > > --0000000000006fbcb005dfb3d076 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Finn,
Where is your fuel filter located?=C2=A0 =C2=A0M= ine in downstream of the pump, but before the fuel injectors.=C2=A0 Fuel pr= essure gauge=C2=A0is just upstream of the filter for me, which I now realiz= e is sub optimal but does provide=C2=A0good info about the state of the fue= l filter.=C2=A0 The pressure starts going up as the filter clogs.

I also have a fuel flow sensor on my return fuel line, whic= h has turned out to be a great troubleshooting tool and reflects the overal= l health of the fuel system.

I am using the walbro= pumps that Tracy recommended.=C2=A0 I bought 10 of them once to have a sup= ply on hand because I never again want to delay replacing them when I see t= he performance start to degrade.=C2=A0 For me, the first sign would be decr= easing return=C2=A0flow.=C2=A0 It more or less seems to linearly decrease w= ith the total time on the pump.=C2=A0 For me, the pressure starts dropping = as the return flow gets closer to zero.=C2=A0 I have taken to replacing the= pump earlier in the process, like 50% reduction in return flow.=C2=A0 With= pumps like the walbro, current demand to the pumps goes up as the flow goe= s down.=C2=A0 At some point the current demand will blow the breaker and te= rminate the flight.=C2=A0 I would guess that fuel pumps seem to last 400 hr= s or so.=C2=A0 This is an improvement since I installed a larger fuel filte= r to keep down the pressure differential.

If your = pumps are similar and your fuel pressure is dropping at the injector, and t= he problem is not a clogging fuel filter, then I suggest you replace the pu= mp ASAP.=C2=A0 They seem fairly susceptible to damage from particulate cont= amination or being run while dry.

Cheers,
Dave Leonard
On Mon, May 23, 2022 at 9:04 AM Steven W. Boese SBoese@uwyo.edu <flyrotary@lancaironline.net> wrote:
Finn,

What the fuel pump should be flowing and what it is flowing may be two diff= erent things and needs to be evaluated before being "comfortable"= .=C2=A0 That is why I would encourage you to measure the actual flow rate i= f you can do it safely.=C2=A0 When I left MS71 in May of 2017 following Charlie's rotary fly-in, my 13B burned 18 gal/hr=C2= =A0on take= -off and initial climb at 5800 RPM and initial OAT of 80 degrees F.= =C2=A0 Your set-up likely would require this much or more.=C2=A0 This was the indication from a Flowscan turbine t= ype sensor which has been demonstrated to be accurate.=C2=A0 The flow measu= rement would just be a next step in the investigation.=C2=A0 If the flow ra= te is not what is what it should be, then determining why would follow.=C2=A0 The replacement pump should be helpful in this reg= ard.

If you recover the fuel being bypassed by the regulator, bubbles in that fu= el will not necessarily indicate air leaking into the fuel drawn into the p= ump.=C2=A0 The process of dropping the pressure when the returned fuel pass= es through the regulator, causes dissolved air in the fuel to separate.=C2=A0 Bubbles in this flow will be obvious.= =C2=A0 If fuel is drawn from a small reservoir (< a gallon or so) and re= turned to that same reservoir where the bubbles are allowed to escape to th= e surface, the bubbles will eventually disappear as the fuel is degassed.=C2=A0 Degassing all the fuel from the wing tank i= s unlikely to occur due to the large volume of fuel and the large surface a= rea of the fuel in the tank.=C2=A0 This is why returning bypassed fuel dire= ctly to the fuel pump intake or to a small unvented header tank (where the separated air is allowed to accumulate) ma= y not be the best practice.

FWIW

Steve Boese

=C2=A0


From= : Rotary motors in aircraft <flyrotary@lancaironline.net> on behalf of = Finn Lassen fi= nn.lassen@verizon.net <flyrotary@lancaironline.net>
Sent: Monday, May 23, 2022 6:25 AM
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Fuel pressure trending lower.
=C2=A0
https://vansairforce.net/community/showthread.php?t=3D= 168793

The GSL414 should be flowing more than 30 GPH at 40 psi. More than double o= f what I need. Does that qualify as "a comfortable amount"?

I have a new one on order. I'll try to hook up my own test.

Finn

On 5/22/2022 11:00 PM, Sboese sboese@uwyo.edu wrote:
Finn,

It seems to me that the problem you=E2=80=99re seeing is c= onsistent with the capacity of the pump not being sufficient for the max fl= ow required by the engine and the pump flow capacity is decreasing with use= .=C2=A0 You appear to have checked everything but the flow capacity of the pump under normal system pressure which is what y= ou really need to know.=C2=A0 If you can divert the returning fuel flow fro= m the pressure regulator to a measuring vessel and and collect that fuel fo= r an accurately measured time, the pump flow rate can be calculated.=C2=A0 This flow rate should be greater than t= he maximum required by the engine by a comfortable amount. =C2=A0

My apologies in advance if this is obvious.

Steve Boese=C2=A0

On May 22, 2022, at 8:05 PM, Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:

=EF=BB=BF

=E2=97=86 This message was sent from a non= -UWYO address. Please exercise caution when clicking links or opening attac= hments from external sources.


Hi Finn

Thanks for the reminder of my pump issue.=C2=A0
Yes, you chose more wisely the pump capacity. Mine were way overkill.<= /div>

So I=E2=80=99m thinking options are:
1. Fuel Pressure transducer fault - No - as this was confirmed by the = mixture monitor and tune going out.
2. Power supply to pump via fault in termination or switch current pat= h - Unlikely, given the slow reduction - I would imagine a faulty connectio= n would create a less uniform symptom.
3. Alternator Battery voltage/current reduction over time - No - You w= ould see this in the log.
4. Significant Fuel leak - No - Would think this would have become obv= ious on inspection and not intermittent.=C2=A0
5. Fuel Regulator - They are pretty simple but unsure if they can fail= with this symptom?
6. Fuel filter blockage - Certainly this would have to be an obvious, = but I take it you swapped this out.
7. Pump internal failure -
Electrical - ?
Mechanical breakage - ?
Flow Path - blockage - unl= ikely if filtered effectively

Where is your pressure transducer in relation to Reg/Any post pump fil= tering/Flow Transducer/Rail?

If fuel regulator and filters can be discounted, I=E2=80=99m strugglin= g to trust the pump. But your test had it sounding in good shape and to spe= c.

So frustrating.

Cheers

Steve





On 23 May 2022, at 8:44 am, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:

Thanks Steve.

>From your March/April 2017 posts it was a GSL392 that failed (high curr= ent draw/low pressure, even after you removed the insect you found in the i= nlet).

So this afternoon I ran the pump for about an hour. Amp draw from 3.04 to 2= 86 depending on voltage. Pressure between 43 and 40 psi (also depending on = voltage). No noticeable degradation. Of course the difference with this tes= t is that no fuel went to engine -- all recirculated through pressure regulator and back to tank. But no si= gns of a failing pump in terms of higher current draw and less pressure.
I guess I should put a temp probe on the pump and see what it reads during = flight to see if that could be a factor.

Finn

On 5/21/2022 9:01 PM, Stephen Izett stephen.izett@gmail.com wrote:
Hi Finn

I had from memory a 393 fail. Can=E2=80=99t recall the symptoms sorry.=

I test before takeoff and then run both pumps below 2ooo ft incase of = failure.
I plan to instal a comparator relay board in fuel pressure circuit to = automatically bring on backup pump and failure indicator.
So testing before flight becomes - switch off and back on main engine = pump. This will save amps and wear of backup pump.
When I switch off a pump at WOT the engine dies pretty much instantane= ously and don't want to be fiddling with a restart in the Glasair which= glides like a brick with the gear out in the breeze.

Regards =C2=A0
Steve Izett





On 21 May 2022, at 10:30 pm, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:

Recently I noticed my fuel pressure being low. Noticed because engine di= d not come up in power when advancing to full throttle. Noticed mixture rea= l lean. Checking fuel pressure as low as 28 psi (normally 35 and up to 40 a= t full throttle).

Going over my engine logs since first flight I now see that fuel pressur= e has been trending lower through each flight -- more pronounced on longer = flights (40+ minutes). More and more pronounced over the months and became = really noticeable over last month. Could explain why mixture tuning appeared to have chang= ed. Nice to have engine logs from practically each flight.

But why? Pump getting weaker?

My primary fuel pump is a GSL414. I figured it was wasted energy to push= way more fuel than needed through the pressure regulator back to the tank.=

My secondary (backup) pump is a GSL393. When turning that on, fuel press= ure comes back up to where it needs to be.

Anyone have experience with failing or weak EFI pumps, particularly the = GSL414?

Finn





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