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  #1  
Old 07-22-2018, 11:48 PM
DrillBit's Avatar
DrillBit DrillBit is offline
 
Join Date: Nov 2007
Location: Pleasanton, CA
Posts: 141
Default Baptized the gas tanks but...prostate problems

OK, so another big day...first gas.

Got 20 gal of 100LL in four 5-gal jerry cans. Took a bit to figure out how to transfer gas 2 gal at a time (into a couple 2 gal cans) to calibrate the left tank. Newfangled spring-loaded safety spouts have to pushed back by a tab bearing on the lip of the container or filler neck of the fillee. I put 2 gal cans against the outside of the hangar door, fill neck face out, keeping them from moving when the 5 gal jerry can bore down on the lip. Thirty pounds of gas is heavy!

The Dynon cap sender circuitry did register a change, but only 440 mV from dry to literally brim full. [The 2 gal pours weren't exactly NIST traceable measurements, so the last 2 of the 18 gals turned out to be >18 gal and a few drops (ahem) spilled on the floor.

OK, the big moment. A 5 gal can in place for the overflow line I rigged up--boost on!

15 sec, nothing.

30 sec, nada.

45 sec, no flow. Holy ****, I couldn't have wired the pump motor bass-akwards, could I have?

Despite a lunch break and searching the interwebs, I didn't find the apparent answer 'till after trying reverse polarity, which didn't work either.

Tune in next week for another exciting episode of "As the Avgas Flows".

Pics etc: http://www.mykitlog.com/users/displa...g=259810&row=1
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P-town, CA (10 min from KLVK!)
N748PK, RV-9A
In final assembly...

VAF dues paid 5 Dec 2017

Last edited by DrillBit : 07-23-2018 at 12:07 AM. Reason: Add url
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  #2  
Old 07-23-2018, 12:14 AM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 5,354
Default

I had the same problem. Pump wouldn’t pump. I siphoned some gas from the tank, thru the pump, over to the engine side. Let it sit for 15 minutes. After that the pump worked fine. My theory is that after years (?) of sitting dry, the seals had shrunk and now wouldn’t seal. Once wet, they worked fine. I subsequentially drained the line, and repeated the test. Pump worked okay, pulled air thru the line until it pulled liquid gas up and over, no problem.

Last edited by BobTurner : 07-23-2018 at 12:17 AM.
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  #3  
Old 07-23-2018, 12:47 AM
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DrillBit DrillBit is offline
 
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Location: Pleasanton, CA
Posts: 141
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Yep...that's the secret sauce I read about in another thread here at the OATV (the Oracle of All Things Vans).

I have an EFII fuel pump, they recommend pouring fuel into the engine side line (temporarily vertical, of course) to wet the innards. What did you use--a small bulb pump thing--to siphon the fuel forward?
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P-town, CA (10 min from KLVK!)
N748PK, RV-9A
In final assembly...

VAF dues paid 5 Dec 2017

Last edited by DrillBit : 07-23-2018 at 12:47 AM. Reason: typo
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  #4  
Old 07-23-2018, 07:39 AM
rv7charlie rv7charlie is online now
 
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Location: Pocahontas MS
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No mention of what kind of boost pump (Facet vs one of the exp injection boost pumps using an auto injection pump).

Note that if it's an auto injection pump designed for in-line use (Walbro GSL393, or the Airtex with plastic ends), it only takes a few minutes of operation without fuel flowing to kill one. The fuel cools the pump. Probably takes a bit longer to kill a Facet, but still not a good idea to run it with no flow.
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  #5  
Old 07-23-2018, 10:02 AM
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dlloyd3 dlloyd3 is offline
 
Join Date: Jun 2005
Location: Locust, NC
Posts: 387
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Similar experience using the Airflow Perf. pump. I wound up putting a little air pressure, 2 psi or so, on the fuel tank vent. That forced fuel into the line and pump. Pumped fine after that. Seems like the Airflow install books says not to run a tank dry as their pump may not self prime.

Running a tank dry generally is not a problem as long as the engine driven pump is available to suck fuel into an empty line.
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RV-7 Tipup, Flying, I0-360,
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  #6  
Old 07-23-2018, 06:59 PM
Flying Canuck Flying Canuck is offline
 
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Location: Red Deer, Alberta, Canada
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Default

Quote:
Originally Posted by DrillBit View Post
OK, so another big day...first gas.

Got 20 gal of 100LL in four 5-gal jerry cans. Took a bit to figure out how to transfer gas 2 gal at a time (into a couple 2 gal cans) to calibrate the left tank. Newfangled spring-loaded safety spouts have to pushed back by a tab bearing on the lip of the container or filler neck of the fillee. I put 2 gal cans against the outside of the hangar door, fill neck face out, keeping them from moving when the 5 gal jerry can bore down on the lip. Thirty pounds of gas is heavy!

The Dynon cap sender circuitry did register a change, but only 440 mV from dry to literally brim full. [The 2 gal pours weren't exactly NIST traceable measurements, so the last 2 of the 18 gals turned out to be >18 gal and a few drops (ahem) spilled on the floor.

OK, the big moment. A 5 gal can in place for the overflow line I rigged up--boost on!

15 sec, nothing.

30 sec, nada.

45 sec, no flow. Holy ****, I couldn't have wired the pump motor bass-akwards, could I have?

Despite a lunch break and searching the interwebs, I didn't find the apparent answer 'till after trying reverse polarity, which didn't work either.

Tune in next week for another exciting episode of "As the Avgas Flows".

Pics etc: http://www.mykitlog.com/users/displa...g=259810&row=1
I had the same problem priming my pump just a couple of months ago, my ordeal was documented here somewhere. The fix ended up being lightly pressurizing the tank through the fuel vent at the front near the firewall. I think I just used a large syringe and a length of clear tubing. It didn't take much and fuel was flowing freely. I only needed to do one tank, the other tank worked fine after I primed with the first.
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Dynon SkyView HDX, IO-320 and WW 200RV C/S. Flying as of August 6, 2018
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  #7  
Old 08-03-2018, 01:40 AM
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DrillBit DrillBit is offline
 
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Location: Pleasanton, CA
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Quote:
Originally Posted by rv7charlie View Post
No mention of what kind of boost pump (Facet vs one of the exp injection boost pumps using an auto injection pump).

Note that if it's an auto injection pump designed for in-line use (Walbro GSL393, or the Airtex with plastic ends), it only takes a few minutes of operation without fuel flowing to kill one. The fuel cools the pump. Probably takes a bit longer to kill a Facet, but still not a good idea to run it with no flow.
Indeed, dry pumping bad.

I have the EFII pump package mentioned in post #3 which uses a Walbro pump. (IO-320 on the nose.)

According to the Walbro website, dry runs should be limited to 5 min max. I ran the pump < 60 sec while troubleshooting, with plenty of time between attempts while scratchin’ the noggin to cool down.
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P-town, CA (10 min from KLVK!)
N748PK, RV-9A
In final assembly...

VAF dues paid 5 Dec 2017
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  #8  
Old 08-03-2018, 12:17 PM
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rcpaisley rcpaisley is offline
 
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Location: Upland, CA
Posts: 251
Default Boost pump

The pump needs to be primed for first use.

Take the fuel line off the servo, back-pour fuel into the line heading back to the boost pump so the internals get wet.

Then you should be good to go. This is just a one time process.
(Also helps to have the wires on with the correct polarity and the pump installed with the correct flow direction - (no names will be mentioned )

Robert
EFII
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Protek Performance
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  #9  
Old 08-06-2018, 12:57 AM
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DrillBit DrillBit is offline
 
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Since a mod moved this to an archived forum* (originally posted to the temp section), I best finish the story in case you, Dear Readers, are wondering what happened...

To get gas to the boost pump, I slid some tygon tubing over the right tank vent and gently pressurized it, blowing into the other end of the tubing. After a short time, gas came siphoning out. Switched the fuel lever to off and let things sit awhile. Fired up the pump (wired as it was originally--the right way round ) and shazam, the pump was pumping.

However, despite the healthier sound coming from the dry pump, fuel flow read 0.0 gallons per hour (could have been firkins per fortnight, for that matter). Tried switching the Dynon EMS configuration to the second flow meter input pin in the Skyview EMS and once again, I had not hooked it up wrong. Easy to try since a software setting is easier than cut wires to reverse. (Besides, the second pin is for a tank return line and reads the opposite of fuel used!) This time, I was smart and decided to read up on troubleshooting Red Cubes before cutting wires or taking apart any plumbing.

In the meantime, I went ahead with baseline fuel flow tests with the a/c nearly level, about +1 degrees. Weighed the receiving jerry can with a fish scale before and after a timed pumping interval. Right tank: 1.9 lb in 30 sec = 228 lb/hr; left tank: 3.6 lb in 60 sec = 216 lb/hr. For an FI 160 HP engine, FAA recommends 1.25 x 0.55 gal/HP/hr x 160 HP = 110 lb/hr. Plenty of margin when level--we'll see what happens when tested at the "anticipated maximum angle of climb."

OK, what about the dang flow sensor? Dynon fora recommended grounding the yellow wire sensing line that goes to the Red Cube. If all is well in the EMS unit and wiring, tapping ground sends pulses and causes the fuel flow counter to advance--which it did. OK, if 12V and Gnd are good (red and black wires, respectively), then the Red Cube has a stuck impeller, dead electronics, or whatever. In the course of cutting the heat shrink away from PIDG knife splices, the red wire pulled out of its knife. Turns out the terminal had cracked too. Odd, first time I've had a bad crimp, or mishandled the terminal, or it had a latent defect to begin with?

Anyhow, the upstream black wire was solid to FoT ground and the red wire had +12.2 V with the bus turned on. I decided if one knife splice was bad, they all may be, so I changed to Dsub barrels and pins to make new splices. Once it was all together again, the fuel flow sensor was alive, and showed nearly the same flows (+/-1 gph) as the measured values above. My supposition is the sensor wasn't getting power before; works like a champ now.

Thanks everyone for the suggestions and advice. I didn't try pouring fuel back through the fire wall, since I had rigged up an overflow line and lashed it down with tywraps.

----

*I suspect it may have been the Lord Mayor of VAFdom himself, DR, since the flow issues made the VAF News front page. Note to self: for maximum VAF exposure, compare RV systems with health issues of men of a certain age...
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Kurt Haller
P-town, CA (10 min from KLVK!)
N748PK, RV-9A
In final assembly...

VAF dues paid 5 Dec 2017
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  #10  
Old 08-08-2018, 04:42 PM
Snoho3 Snoho3 is offline
 
Join Date: Dec 2012
Location: Snohomish, WA
Posts: 87
Default Speaking of gas can spouts -

FWIW - The original post started by mentioning what a pain it is to pour gas from a 5 gal can into the aircraft tanks with the new-fangled safety spouts. Maybe I'm the last to realize this, but Tractor Supply (and Amazon, and...) sell cheap replacement kits for the original spouts that don't have that god-awful safety spring/lip. Very very easy to punch a hole in the 5 gal can to add the plastic pressure relief valve, then you are good to go with the old style spout.

Not filling my -9A project just yet, but gassing up my mower and tractor are a lot simpler and cleaner. Just thought I'd throw this out there.
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