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High Fuel Pressure Alarm

W

Walt Shipley

Active Member
During taxi tests, with engine rpm at approximately 3,000, I frequently get the "High Fuel Pressure" warning. When this happens the pressure hits the redline of, I believe, 5.8 psi. Normally, my pressures run in the yellow at
around 5.5 psi.

I've read several posts by others who have the same problem and have elected to solve it by installing a Kavlico sensor. But, I really don't want to
spend the money and time on a new sensor. I'l like to get the old one to work properly, I wonder if there is a way to set the redline a tad higher - say
6.0 psi or so. Of course, I don't want to do something that would damage the
engine.

If I DO decide to get the Kavlico, how much do they cost?

Walt Shipley
 
See.
http://www.vansairforce.com/community/showthread.php?p=632255
Page 2.
If you intend to buy the new version fuel pressure sender,
Dynon part number 101690-000 Carbureted Fuel/Fluid Pressure Sender-Kavlico, 1/8-27 NPT, 15 PSI , $85
... don't get it from Dynon - they charge a $20 fee plus shipping. In fact they recommend that you use one of their retailers. Aircraft Spruce is one of them, their part number 10-04820, DYNON KAVLICO CARB FUEL SENSR, $83 plus $2 shipping by mail.
 
Walt Shipley said:
During taxi tests, with engine rpm at approximately 3,000, I frequently get the "High Fuel Pressure" warning. When this happens the pressure hits the redline of, I believe, 5.8 psi. Normally, my pressures run in the yellow at
around 5.5 psi.

I've read several posts by others who have the same problem and have elected to solve it by installing a Kavlico sensor. But, I really don't want to
spend the money and time on a new sensor. I'l like to get the old one to work properly, I wonder if there is a way to set the redline a tad higher - say
6.0 psi or so. Of course, I don't want to do something that would damage the
engine.

If I DO decide to get the Kavlico, how much do they cost?

Walt Shipley
Click to expand...

A couple things to consider...

The max. pressure red line is specified for a purpose (refer to the the 912 install manual). Raising the red line limit is not much different than installing a larger fuse when it keeps blowing.

If you have an engine with the new style pump, it might be bad. Some of the early pumps had too high of an output pressure. This problem primarily occurs at or near idle because of the very low fuel flow.

If you have a new style pump, I recommend you look into getting a warranty exchange for the pump.
 
Many of us have seen hi fuel pressures with the new style pump just after it was installed. The pressure seems to stabilize in the normal band after about 10 hours of operation. "Break-in"??
 
MartySantic said:
Many of us have seen hi fuel pressures with the new style pump just after it was installed. The pressure seems to stabilize in the normal band after about 10 hours of operation. "Break-in"??
Click to expand...

Possibly.

The new pump was designed to have a bit higher output pressure than the ones supplied previously, but some of the early ones over did it just a bit.

If you run with pressures above 5.8 PSI you are risking overwhelming the float valves which will cause flooding of the engine. Not a problem taxiing on the ground, but very inconvenient during a power off glide for landing.
 
High fuel pressure

For what it's worth...
I had the same type of high fuel pressure readings. The slip on spade connectors on the sensor could have a high resistance which will cause the red line indications. I solve this problem by replacing the slip on connectors with ring terminals.
This fix will cost you nothing and is very easy to do. See my thread here: http://www.vansairforce.com/community/showpost.php?p=635215&postcount=1

At the very least it will eliminate the connections as the problem.

Tony
 
High Fuel Pressure

Thanks to those of you who offered suggestions to take care of my high fuel pressure warning on the Dynon.

I tried changing the spade connectors to ring connectors with no improvement. Next, I removed the fuel line from the VDO pressure sensor and installed an oil filled pressure gauge.

After starting the engine, I found the fuel pressure to be between 4psi to around 4.8psi, with the higher number occuring at idle rpm. This tell me the
engine fuel pump is working properly and that the problem is either the VDO sender, the wiring or the D180. I have checked my wiring carefully and
I don't think that is the problem. Since so many RV-12 builders have had problems with the VDO senders, my guess is that is the problem. As such, I've ordered the Kavlico and should recieve it in a few days.

Now that I've made the "Kavlico" decision, I'm not looking forward to reprogramming my D180. Can someone give me an idea of just what needs
to be reprogrammed to make the Kavlico work? I've read that the Kavlico needs 5V power run to it, and that I don't think will be difficult, but reprogramming? I'm definitely not looking forward to that.

Any help will be greatly appreciated...

Walt Shipley
 
Kavlico sensor upgrade

With the D-180 turned on, measure the voltage on each of the two wires connected to the old fuel pressure sender. Determine which of the two wires has voltage on it and which is the ground wire. Mark the positive wire with BLUE tape. This is the SIGNAL wire. Mark the grounded wire with black tape. Tap into the WHT/RED wire going to the manifold pressure sensor on the firewall to get 5 volts. Now you have the 3 wires required for the Kavlico sensor: 5VDC, GROUND, and SIGNAL going (through the control board) to pin 8 of the Dynon EMS.
If your D-180 does not have the latest version of firmware, download it here: http://www.dynonavionics.com/docs/support_software_151211.html
Or if you have an autopilot with frequent "Nav Source Lost" errors, consider trying firmware beta version 5.5.A0 from Dynon:
http://dynonavionics.com/downloads/Software/Dynon%20Support%205.5.A0.exe
Download this document from Dynon:
http://www.dynonavionics.com/downloads/Install_Guides/Addendum_Kavlico_Sensors-Rev_B.pdf
It tells you how to configure the new Kavlico fuel pressure sensor in the D-180.
Joe Gores
 
Last edited:
Joe, regarding your comment on the new firmware correcting the "Nav Signal Lost", did you download this and did it solve that problem for you? Yea, I know, thread drift!
 
Fuel Pressure Alarm

Guys, as I said before I have had a high fuel pressure alarm at idle and have narrowed it down to the old type sender. I installed a Kavlico sender and now I'm preparing to install Dynon firmware 5.4.3 into my D180.

I think I have a pretty good understanding about how to do the firmware update (I downloaded it to my computer and I have the Dynon support program on how to accomplish installing it into my D180) but, what I'm concerned about is how and when to upload Van's unlock software to the D180. At this point I have downloaded the unlock to a WinZip file on my computer. My question really is, how do I get this information into the D180?

When I look at the unlock file on my computer I see things like "zip send", "1 click unzip", "unzip & install", etc., none of which makes any sense to me.

This is the last item holding up my first flight. I will be very grateful to anyone who can help me get over this last hurdle.

Thanks,

Walt Shipley

P.S. Joe, I really apprececiated your detailed instructions on installing the Kavlico sender. That really helped.
 
Since you have already tried unzipping Van's Locked settings, let's assume that the file was successfully unzipped. The next step is to locate the unzipped file on your computer. Look for a file named "Vans_RV-12_EFIS-D100_locked_settings_5.4.3.efs" If you can not find it, get a local computer nerd to help.
At some point during the Dynon firmware upgrade process, it will ask for the locked setting file. You need to tell the Dynon Support program where the Vans_RV-12_EFIS-D100_locked_settings_5.4.3.efs file is located. Get a local computer nerd to help if necessary.
Joe Gores
 
On my 0-320, bleeding the fuel pressure line (by disconnecting it at the transducer and turning on the boost pump until fuel comes out) seemed to have solved my problem of a high/erratic fuel pressure reading. I was going to go Kavlico but don't need to, at least for now, which is good because I didn't run an extra 5V excitation wire through the firewall like I should have!:eek:
 
MartySantic said:
Many of us have seen hi fuel pressures with the new style pump just after it was installed. The pressure seems to stabilize in the normal band after about 10 hours of operation. "Break-in"??
Click to expand...

This is what I have experienced, but it took about 30 hours. The very day that I called Lockwood's regarding the high pressure, it went down to and has stayed dead center of the green. I like it when these things fix themselves!
 
New pump and Sensor - High fuel pressure

rvbuilder2002 said:
Possibly.

The new pump was designed to have a bit higher output pressure than the ones supplied previously, but some of the early ones over did it just a bit.

If you run with pressures above 5.8 PSI you are risking overwhelming the float valves which will cause flooding of the engine. Not a problem taxiing on the ground, but very inconvenient during a power off glide for landing.
Click to expand...

There are quite a few threads on this subject; I think I've red all of them half a dozen times. My airplane -17.4 Hobbs - began flashing high pressure warnings - 5.9 - 6.2 psi, in the last few hours - at start-up, and also at altitudes between 7500 and 10,000 ft. Same with the electric pump on or off. I have the new pump and the new sensor, both installed from the get-go.

Someone was admonished for raising the Dynon alarm setting as the equivalent to upping the size of an electrical fuse to keep it from blowing.

After reading the threads - I removed the new sensor and checked it and the supply hose for the mysterious red goop reported by a number of operators. No goop. No red anything. Then I flushed the supply line into a container using the electric pump - nice clean fuel.

Concerned about the carb float valves and flooding the engine, I expanded my research talking to Jim Scott in Arlington, Wash. and Aaron at Lockwood. Jim Scott said raise the warning to 6.5 psi, the new pumps were set high and ran high.

Lockwood pointed me to Rotax Service Letter 912-020 Rev 6 Page 6 dated 3 Sept 2012, which upped the Max Fuel Pressure Operating Limit to 7.26 psi.

I think I just solved my "problem", and hope I have solved everyone else's problems with high fuel pressure, once and for all. Now - if you have the new puimps installed - go out and reprogram your Dynon warning settings!

Bob Bogash
N737G
 
Thanks Bob for that helpful info.

I was changing the fuel flow settings in skyview and messed it up.
I would appreciate the green, yellow and red parameters using the new
6.2 value.

Thanks
 
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