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sarg314(at)gmail.com Guest
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Posted: Wed Nov 03, 2010 7:47 am Post subject: AFP and fuel pressure and fuel pump |
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I have the AFP fuel injection unit on my RV-6A and a VM-1000 to monitor the fuel pressure. When I first started flying it (about 15 hours ago) the fuel pressure read about 26 psi running on the engine driven pump and would go to 27 when I switched on the boost pump. The pressure produced by the engine's pump has slowy been decreasing. It now shows about 24psi and even 23psi once. Turning on the boost pump always brings it back to the 26 - 27 range (after a brief surge up to 35 or so). The engine seems to run OK either way.
So, I think the pressure sensor is OK. Is it normal for a fuel pump to sag a little in the first 15 hours of operation, or do I have a nascent problem on my hands?
Does any one know the miinimum fuel pressure that AFP needs?
Thanks,
--
Tom Sargent, RV-6A
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wgill10(at)comcast.net Guest
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Posted: Wed Nov 03, 2010 8:21 am Post subject: AFP and fuel pressure and fuel pump |
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Tom,
I occasionally experience the same problem, but it seems to be related to having full tanks -- perhaps the fuel vent line is full of fuel causing the pump to work harder. If I switch tanks, the pressure returns to 25psig. Again, it only happens with full tanks and usually lasts no longer than a minute or so...been that way since first flight almost 800 hours ago.
Best regards,
Bill
RV-7 N151WP
Lees Summit, MO
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panamared505(at)brier.net Guest
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Posted: Wed Nov 03, 2010 8:23 am Post subject: AFP and fuel pressure and fuel pump |
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Not a big deal. You are still within limits with 23 PSI. I have been flying for 8 years with a Bendix system and I don't ever get the same reading from flight to flight. I don't recall the minimum fuel pressure, but the answer should be in your Lycoming engine manual. It is not what AFP needs but what the engine needs that is important.
Bob
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recapen(at)earthlink.net Guest
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Posted: Wed Nov 03, 2010 8:52 am Post subject: AFP and fuel pressure and fuel pump |
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Tom,
Here's what I see on a regular basis (2yrs approx 90 hrs):
Startup is about 17 or so but builds to 30 pretty quickly and then stays there - boost pump takes it to 33 or so and I've seen it fade down to 29 but come back to 30.
You may be seeing an electrical resistance increase due to heat where the sender is mounted. Make sure the sender sees a good ground path.
My thoughts,
Ralph
RV6A N822AR (at) N06 - AFP on my XP360 - SJ cowl...just back from paint.
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rice737(at)msn.com Guest
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Posted: Wed Nov 03, 2010 4:28 pm Post subject: AFP and fuel pressure and fuel pump |
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Hey Tom,
I am running the same combination on my -8 and see almost identical numbers to yours. I have been flying mine for over three years and think maybe it was higher in the beginning. I wouldn't worry about it, just monitor it and have a good time flying. Only other thing I might suggest is remove and clean the sensor and see if that makes any difference at all.
Paul Rice
RV8 / 250 hours
Date: Wed, 3 Nov 2010 08:43:43 -0700
Subject: AFP and fuel pressure and fuel pump
From: sarg314(at)gmail.com
To: rv-list(at)matronics.com
I have the AFP fuel injection unit on my RV-6A and a VM-1000 to monitor the fuel pressure. When I first started flying it (about 15 hours ago) the fuel pressure read about 26 psi running on the engine driven pump and would go to 27 when I switched on the boost pump. The pressure produced by the engine's pump has slowy been decreasing. It now shows about 24psi and even 23psi once. Turning on the boost pump always brings it back to the 26 - 27 range (after a brief surge up to 35 or so). The engine seems to run OK either way.
So, I think the pressure sensor is OK. Is it normal for a fuel pump to sag a little in the first 15 hours of operation, or do I have a nascent problem on my hands?
Does any one know the miinimum fuel pressure that AFP needs?
Thanks,
--
Tom Sargent, RV-6A
[quote]
m
A>
ist
[b]
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martinaerodrome(at)gmail. Guest
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Posted: Thu Nov 04, 2010 5:40 am Post subject: AFP and fuel pressure and fuel pump |
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I have experienced 5 or 6 fuel pumps during the 2000 hours that I have on my RV8. They usually last 400 or 500 hours, however, I just replaced one (they warrantied it) that failed in less than 25 hours. I have an IO390 lyc engine . I also use a Airflow Performance electric standby fuel pump. The standby pumps usually last indefinetly.
Good Luck
Dick Martin
RV8 N233M
the fast one
On Wed, Nov 3, 2010 at 11:17 AM, <wgill10(at)comcast.net (wgill10(at)comcast.net)> wrote:
[quote]
Tom,
I occasionally experience the same problem, but it seems to be related to having full tanks -- perhaps the fuel vent line is full of fuel causing the pump to work harder. If I switch tanks, the pressure returns to 25psig. Again, it only happens with full tanks and usually lasts no longer than a minute or so...been that way since first flight almost 800 hours ago.
Best I,
Bill
RV-7 N151WP
Lees Summit, MO
---
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ghinman(at)mts.net Guest
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Posted: Thu Nov 04, 2010 8:06 am Post subject: AFP and fuel pressure and fuel pump |
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I have a Bendix FI on my O360
In flight fuel pressure is about 24 with boost off
about 27 with boost on
If I am slow taxiing with a warm engine it drops to about 17
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George H. Inman
ghinman(at)mts.net
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