What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Kavlico reliability poll

hgerhardt

Well Known Member
Rather than muddying up the other recent Kavlico posts, It would be nice to get a better picture of the failure rate of these sensors.

IF YOU HAD A FAILURE please post:

Purchase date of the sensor (roughly)
How long it had been in service, both years and hours of use
Oil pressure or fuel pressure application
What went wrong? Leak, functionality issue?

Edit: as Bill suggested; If fuel sensor leak, state FI or carbureted, and which hoses/other plumbing you used; Vans, TSFlightlines or other. The next time you fly on a hot day, check your fuel pressure 8-10 min after shutdown and report.

Trying to narrow down if this is an infant mortality thing or if there was a bad batch(es) or if they tend to die an early death.

Dynon/Garmin/Van's please fill us in with what you know about this.

Heinrich
 
Last edited:
I just talked with Dynon and the rep said that "only a very, very small" number of the sensors have been reported as leaking. This is a proactive measure and replacing them is entirely your choice.

My original sensors are two years old and unused, never even out of the packaging. No replacement credit for them.

The new ones are maybe a few weeks out. They weren't in stock yet. They'd be more expensive than the original but he didn't have prices yet.

Dave
 
Rather than muddying up the other recent Kavlico posts, It would be nice to get a better picture of the failure rate of these sensors.

IF YOU HAD A FAILURE please post:

Purchase date of the sensor (roughly)
How long it had been in service, both years and hours of use
Oil pressure or fuel pressure application
What went wrong? Leak, functionality issue?

Trying to narrow down if this is an infant mortality thing or if there was a bad batch(es) or if they tend to die an early death.

Dynon/Garmin/Van's please fill us in with what you know about this.

Heinrich
The post should include if the plane is O or IO. I suspect injected engines are the only ones getting hit. Also, if injected, state what hoses you used, Vans, TSFlightlines or other - be specific.

The next hot day (the engine needs to be fully hot as from a flight), check fuel your fuel pressure 5 min after shutdown. {changed 5 min to match Garmin SB}
 
Last edited:
I've had a constant weep from my oil pressure sender since day 1. I've never considered it dangerous, just an annoyance, but after reading the SB, I'll be pulling it soon as new sensors are available.
 
I upgraded and installed a Dynon EMS D10 new with Kavlico pressure sensors back on 10-01-2012 (almost 8-years) with 2,654.7 on my Hobbs. I now have 3,472.5 on the hobbs.

The Kavlico pressure sensors have work flawlessly for 817.8 hobbs hobbs hours. I find the Kavlico pressure sensors installed in my airplane more reliable and more accurate than the VDO sensors they replaced.
 
Last edited:
Rather than muddying up the other recent Kavlico posts, It would be nice to get a better picture of the failure rate of these sensors.

IF YOU HAD A FAILURE please post:

Purchase date of the sensor (roughly)
How long it had been in service, both years and hours of use
Oil pressure or fuel pressure application
What went wrong? Leak, functionality issue?

Edit: as Bill suggested; If fuel sensor leak, state FI or carbureted, and which hoses/other plumbing you used; Vans, TSFlightlines or other. The next time you fly on a hot day, check your fuel pressure 8-10 min after shutdown and report.

Trying to narrow down if this is an infant mortality thing or if there was a bad batch(es) or if they tend to die an early death.

Dynon/Garmin/Van's please fill us in with what you know about this.

Heinrich

Purchased with all my Garmin goodies (I think), about 2017 the Kavlico sensors for MP, Oil Press, and Fuel Press. The first fuel pressure sensor, P4055-50G, failed in the summer of 2018 at roughly 25 hours flight time after less than 2 months in service. The first failure was electrically, meaning no readout to the engine monitoring system. Garmin sent me another (warranty), and it failed in 2020, after 150 ish hours in service, which was a mechanical and electrical failure-quit reading and leaked fuel too. This was on an IO-540 Lycoming.
 
I'm pretty sure ours is failing due to a slight smell of fuel only on climb out. Will be verifying later today or this weekend.
 
I'm pretty sure ours is failing due to a slight smell of fuel only on climb out. Will be verifying later today or this weekend.

I get that on my 6 occasionally after topping off the tanks on a warm day (only on climb out) and it is related to expanding fuel being pushed out of the tank vents. Leakage from a fuel pres sensor should drip down near the cowl exit and will go out with the cowl cooling air. If you can't smell exhaust in the climb, it seem unlikely that you would smell fuel that is coming out the cowl exit.

Venting fuel from the tanks comes out near the side of the fuse and there are several areas of negative pressure near the wing root and doors.

Larry
 
Last edited:
Request Additonal Information on the Sensor Poll

I would like to ask if you guys can add what type of fuel pump setup you have, such as Andair pump (part number XYZ) or Vans pump (model XYZ) or EFII pump (model XYZ), or other automotive pump.

I have the newer pump from Vans and it is restricted to 30psi. I am not sure if the older pump is restricted like the newer pump. I am hoping the information can add to the data points as well.

Thanks
 
My VDO fuel pressure sender started failing (high readings) last year. I put in a Kavlico 50psi for fuel injected engine sensor. No issues.
 
My question...

I am not flying yet but my question is should I replace my FP sensor? Are the new ones a different design?
 
Purchased with all my Garmin goodies (I think), about 2017 the Kavlico sensors for MP, Oil Press, and Fuel Press. The first fuel pressure sensor, P4055-50G, failed in the summer of 2018 at roughly 25 hours flight time after less than 2 months in service. The first failure was electrically, meaning no readout to the engine monitoring system. Garmin sent me another (warranty), and it failed in 2020, after 150 ish hours in service, which was a mechanical and electrical failure-quit reading and leaked fuel too. This was on an IO-540 Lycoming.

Larry, what hoses do you use for the sensor and from the mechanical pump to the servo? TSFlightlines or Vans?

When you run the shut down pressure rise test please post the data.
 
Larry, what hoses do you use for the sensor and from the mechanical pump to the servo? TSFlightlines or Vans?

When you run the shut down pressure rise test please post the data.

Help me understand how the manufacturer of the lines could influence the issue? I'm not being snarky, I'm just trying to understand why they are collecting that information.

As to the pressure rise after shutdown, isn't that something which the manufacturer or integrator should have anticipated in this application?
 
Why a 5-minute check?

The post should include if the plane is O or IO. I suspect injected engines are the only ones getting hit. Also, if injected, state what hoses you used, Vans, TSFlightlines or other - be specific.

The next hot day (the engine needs to be fully hot as from a flight), check fuel your fuel pressure 5 min after shutdown. {changed 5 min to match Garmin SB}

What's the purpose for checking fuel pressure 5 minutes after shutdown? Should it increase or decrease? Or would that be a bad thing?
I don't see anything about this from Dynon or Van's.
 
I had not read the Garmin SB when I first posted, so guessed at the time. Garmin asks for 5 min in the SB following a hot shutdown.

On engine shutdown with most injected engines, the fuel is trapped in the two fuel hoses between the servo mixture shut off and the exit check valve in the fuel pump. If the fuel is all liquid and expands after shutdown then that expansion will increase the trapped volume, thus increasing the pressure. The peak pressure will depend on the stiffness of the hose. They are not all the same.

The mixture shutoff is apparently not a perfect seal (per Airflow performance document on purge valves) and a leaker will release more or less.

Help me understand how the manufacturer of the lines could influence the issue? I'm not being snarky, I'm just trying to understand why they are collecting that information.

As to the pressure rise after shutdown, isn't that something which the manufacturer or integrator should have anticipated in this application?

It should have been, and may have been, anticipated but it is important to gather in root cause analysis.

What's the purpose for checking fuel pressure 5 minutes after shutdown? Should it increase or decrease? Or would that be a bad thing?
I don't see anything about this from Dynon or Van's.

See the Garmin SB, deep in the list of actions to take is a shutdown test.

On a personal note. I had this same issue on a project a few decades ago. The fuel was ethanol, and all went well with the project development until a pre-production change was made in the hose material between the pump and injector. The situation above existed and the hose used for 2 years in development and testing happened to allow all to work well, but the new hose resulted in higher pressure, 300 psi to be exact, and the injector would not fire over 125psi.

Bottom line: it might be the cause of failure, or may not, but only data will tell.
 
i have a carb so it should not effect the fuel pressure, but the oil pressure sender could be effected. mine has been good for seven year with no leaks. another data point that might be good to collect, is there a restriction fitting in the line going to the sensor. some people have not installed one in their lines.

bob burns
rv-4 N82RB
 
To have a crack at answering Kyle's question, fluids are considered the flexibility of the hose type will allow for some volume expansion and subsequently reduce pressure buildup as the fuel heats up, tries to expand and subsequently increases in pressure. I looked at my data last night, and at shutdown I have about 30psi at the system. 40 seconds later I have 51psi in the system.
To answer Bob's question, I have a relatively stock fuel system with an Andair electric pump and a IO-360M1B with a stock mechanical pump, and I'm exceeding the design value of the standard 50psi sensor just 40 seconds after shutdown. I still don't know what this goes to at 5 minutes after shutdown when the system is fully heat soaked, but since I already exceed the limit, I'm ordering a new sensor with the higher pressure rating anyway.
Tom.
 
Looking at the datasheet for the P4055-50G (what we're using for FI fuel pressure application), they're rated to 100 PSI proof and 150 PSI burst. Hard to believe that we can exceed 150 PSI during heat soak.
 
Hmm and double hmm.

The fuel pressure readout on my RV-9A (carbureted, Garmin G3X) has always been flaky with apparently spurious low pressure readings. Replaced the fuel pump (ouch!) and the fuel pressure sender, no change. Wiring? Dunno.

No leak has been found around the fuel pressure sender, but just this week, the IA found a drop of blue liquid on a hose near the aft end of the engine, but no source. (He was timing the mags and gave things a look-see while things were apart).

So today I took the top cowling off to comply with the service bulletin. No leaks found around any of the pressure sensors. Found the model number for the manifold pressure sender, but it was partially obscured by the SkyBolt fastener flange and I couldn't read it -- part of the problem being I needed stronger reading glasses.

The other two pressure senders had no model number on the brass part. One of those was the aforementioned fuel pressure sender, but I no longer have the invoice, so I don't know what part it is.

I used to snicker at the suggestion of keeping lists of all the components and serial numbers when you build a plane. Now I think it's a really good idea...
 
P4055-50G sensor about a year old, 50 hrs in service, RV-14A stock Van's FWF hose setup, IO-390 Standard, Andair pump that came with the kit. Sensor failed electronically first with a big red x on the Dynon, then the leak. I had flown from Heavens Landing, GA to Bartow, FL and fueled up upon landing. At engine start the fuel pressure had the big red X but I had good flow and engine ran flawless on run up. Flew back to Heavens Landing about 2.5 hours. Upon landing I noticed several blue streaks coming out of the cowling. Removed the cowling to find lots of blue dye all over the engine mount and firewall. I suspected the fuel pressure sender and after removing the plug and turning on the boost pump I confirmed that the sensor was leaking out of the electrical plug. Replaced with a new sensor and have flown another 50 hours and never thought about it again until I saw the notice from Dynon.
 
IO-360, van?s fuel lines, G3X, garmin P4055-50G fuel sensor. Less than 1 yr old, and 100 hours on it. After hot shutdown, saw 49.1 psi max pressure. Cranked up again and ran on the ground for a few minutes, shutdown, and pressure rose above 50 psi (after 50 it showed dashes - -.- because was only set up to read max of 50).

No leaks, but wondering if I should switch to the 75 psi sensor even though the 50G is supposedly good to 150 psi.
 
I just ordered a new fuel sensor. They are now PMA and cost around $225.00. Mine wasn't leaking and never has. However: I spent 26 years in aircraft maintenance in the USAF and if there is a part that is suspect now and you can replace it with an upgraded part then do it. Fuel in the engine bay is not an acceptable risk I am willing to take. Gold plate it! Manifold pressure and oil pressure sensor is not as concerning than fuel. Just MHO.
 
Out of range!!! THANKS!!!

IO-360, van?s fuel lines, G3X, garmin P4055-50G fuel sensor. Less than 1 yr old, and 100 hours on it. After hot shutdown, saw 49.1 psi max pressure. Cranked up again and ran on the ground for a few minutes, shutdown, and pressure rose above 50 psi (after 50 it showed dashes - -.- because was only set up to read max of 50).

No leaks, but wondering if I should switch to the 75 psi sensor even though the 50G is supposedly good to 150 psi.

That is something I did NOT think about. I am going set mine higher when I get the plane back to do this test. Real data is required to know. For $250 I can reset the range to check.
 
In order for these new 150psi sensors to work in the G3X and G3X touch, Garmin would have to update the software.


Garmin, are you planning this as a future upgrade?
 
In order for these new 150psi sensors to work in the G3X and G3X touch, Garmin would have to update the software.


Garmin, are you planning this as a future upgrade?

You can easily go into the setup mode and program custom sensor inputs using whatever sensor you want. All you need is the upper and lower voltage outputs vs pressure.
 
Hi Walt,
Yes I know you could do it that way It would be easier if they just made the specific sensor a selection in the menu, just like the others are
 
Finally got around to checking my pressure after hot shutdown and started with 29.0 PSI and about 2 mins later went up to 29.5 and then slowly decayed to about 25 PSI 15 min later. My original-from-2013 Kavlico 50 PSIG sensor is connected to a ~12" long -1 size teflon hose Tee'd off at the mechanical fuel pump outlet and with the sensor body Adel-clamped to my fuel filter housing on the firewall.

So on my RV, there is no hose high up in the heat like typical RV's with the aluminum sensor manifold on the firewall. Is that a significant difference? Or does my system just have (enough) leakage in the boost or mech pump check valve or FI servo to eliminate the pressure rise? Who knows.
 
Last edited:
Finally got around to checking my pressure after hot shutdown and started with 29.0 PSI and about 2 mins later went up to 29.5 and then slowly decayed to about 25 PSI 15 min later. My original-from-2013 Kavlico 50 PSIG sensor is connected to a ~12" long -1 size teflon hose Tee'd off at the mechanical fuel pump outlet and with the sensor body Adel-clamped to my fuel filter housing on the firewall.

So on my RV, there is no hose high up in the heat like typical RV's with the aluminum sensor manifold on the firewall. Is that a significant difference? Or does my system just have (enough) leakage in the boost or mech pump check valve or FI servo to eliminate the pressure rise? Who knows.

I have read the ICO valve is a rotating disc and they may not all have an absolute seal. The range of leakage or lack thereof would definitely make a pressure difference.

If my pressure turns out that low then there is no reason for a sensor replacement.
 
Back
Top