Recently my fuel flow readings went from about 9 gals per hr. To around 16 gallons per hour,would these be a bad fuel flow transducer?. I have the lycoming io-390 thunderbolt with ft-60 fuel flow transducer.it’s mounted per plans for the van’s manual.
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Fuel flow
- Thread starter Dennis Harm
- Start date
No I didn’t,what type of shield did you use?
Hi Dennis,
I had similar issue with the exact same configuration: RV-14, IO390 TB, FT-60, FM-200C and found the culprit after a lot of troubleshooting... Let me ask you this:
Does the fuel flow increase happens at full rich mixture or when you reduce or move your mixture lever?
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Problem seems to happen after I lean after level out
Same thing with me. Turns out my fuel controller had an issue. I sent it back to factory and it was replaced.
Make a simple test: unhook the fuel hose that goes from fuel controller to the fuel spider, run the boost pump with mixture full reach and then lean the mixture. It is expected that volume of fuel would reduce as mixture is leaned. In my case my fuel flow would pick at middle mixture travel. About 25gph. And then would cut off normally.
My fuel controller apparently was wrongly assembled. Luckily full rich worked as expected. But took me a while to figure it out. Swapped fuel flow sensor and all…
I have a video of the test I did. Sounds crazy but it actually happened ..
Another way to see if it's a sensor error or a "real" error is to look at the EGT. A change in FF this large would show up in the EGT numbers.
jeffreyuh60
Well Known Member
The problem, my friend, is that you’ve been cooking that Northern bird in Florida for too long. It’s time to come back home to Wisconsin
I bet it has nothing to do with the flow meter because looks like Dennis is not having erractic readings.. it is consistently wrong and with strange behavior..
Here is the link to video where I had similar issue. @Dennis Harm , check out the fuel flow in the middle of mixture travel:
Here is the link to video where I had similar issue. @Dennis Harm , check out the fuel flow in the middle of mixture travel:
One of the rule is not to have a sharp bend (90) to or from the cube
Correct, this is the reason I used the expensive smooth tube bend fitting. 550 hours and this install has worked perfectly.One of the rule is not to have a sharp bend (90) to or from the cube
On the RV-14 that I fixed, the fuel flow work well until climbing above ~4000’. At that point indicated fuel flow went to ~14GPH regardless of mixture or throttle control That cube was installed exactly to plans. Talking to Van’s at the time I got the impression that this was not the first report.
Replacing the cube resulting in the exact same behavior. Moving the cube fixed the problem.
Carl
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I am glad that it has been fixed and will go to concede some of those rules are perhaps just best practices and not an absolute. Needless to say that both of my 14s which have the Cube installed in the general location as VANS plans have had very accurate (within .2G at 30G fill up) reading with no issues at all. I also worked on a friends 14 which has it installed in the same location with no issues at all.
Hi everyone that posted,I’ve got a new red cube on order along with some insulation material.I’ll install them and post the results,thanks for all the replies.
Um, please forgive my dumb question, but what tape did you use?
Bare heat shields are poor performers, and it's easy to make better ones. Same principles apply to insulating a cube.
Ordinary soft aluminum tape (sold for for duct sealing) is your friend.
The Van's supplied hose from the pump to the servo (390, RV-14) is typically too long, thus too close to the exhaust headers on the left side. And the best place for the cube is somewhere between the servo and the divider. Flightlines has a nice bracket to mount it next to the divider.
Home brew exhaust heat shields
I was a little concerned about how close the exhaust runs under the throttle cable, so in addition to firesleeving it, I spent some time today busting out a exhaust heat shield. I made it out of .025 scrap with the tab that the band clamp slides through .032. I made the first one too short, so...
www.vansairforce.net
Ordinary soft aluminum tape (sold for for duct sealing) is your friend.
The Van's supplied hose from the pump to the servo (390, RV-14) is typically too long, thus too close to the exhaust headers on the left side. And the best place for the cube is somewhere between the servo and the divider. Flightlines has a nice bracket to mount it next to the divider.
