high oil pressure & high fuel pressure - after overhaul:

[sekomel]

hi everyone

hope this message finds you all very well.

My engine is ready after the overhaul process and we did the first start yesterday.

At very first start, I saw high oil pressure & high fuel pressure - both were on the red line. I immediately shutdown the engine. After that the engineers fixed the oil pressure issue (they re-adjusted again) however the fuel pressure was still way too high.

Do you guys have any suggestions or experience about this? We checked everything, bypass hose, fuel pump, all the system etc..but still nothing..

If you guys have any opinions, suggestions, more than welcome..

Wish you healthy days,

seko

[carusoam]

Hey Seko!

Have a search around here for the Fuel pressure issues on OH’d engines from Lycoming…

This was a common occurrence a while ago…

Unfortunately, I don’t remember enough detail to point you in the right direction…

I think @jetdriven is familiar with this challenge… (high fuelP in OH’d IO360)

Good luck with your next steps… you are almost there!

Best regards,

-a-

[ArtVandelay]

If this is a FI Lycoming, they change the fuel pump so it goes above 30 psi, especially during idle, after break-in mine drop below red line. Unless it’s way higher, like above 32 psi I wouldn’t worry about it.

[Ragsf15e]

53 minutes ago, sekomel said:

hi everyone

hope this message finds you all very well.

My engine is ready after the overhaul process and we did the first start yesterday.

At very first start, I saw high oil pressure & high fuel pressure - both were on the red line. I immediately shutdown the engine. After that the engineers fixed the oil pressure issue (they re-adjusted again) however the fuel pressure was still way too high.

Do you guys have any suggestions or experience about this? We checked everything, bypass hose, fuel pump, all the system etc..but still nothing..

If you guys have any opinions, suggestions, more than welcome..

Wish you healthy days,

seko

Exactly what @ArtVandelay said.  I had a new fuel pump put on last year and it sits right at redline, maybe just over.  At full power in cruise it’s just barely below redline.

Sounds like your mech adjusted the oil pressure, but you’ll definitely see higher oil pressure after start until the oil gets hot.  Maybe not redline at idle, but maybe still noticeably high.  It will be higher with greater than 1000 rpm too.

[Guest]

The Lycoming limits differ from Mooney limits. 
Clarence

[sekomel]

hi everyone

thanks for the answers!

my new pump was original lycoming (please see attached below)

part no: LW-15473

 

and the new fuel pump is not original lycoming one, part no is: 

AF-15473 High Fuel Pressure Pump

 

So above comments and from the other topics, I understand this is normal unless it’s get crazy..

 

thanks a million for your hep again, I wi update here if anything’s happen..

thanks

seko

 

[N201MKTurbo]

For some reason somebody decided the spring needed to be stiffer. It seems it is the only spring available nowadays. The spring determines the fuel pressure of the mechanical pump. They all make 30+PSI.

[ArtVandelay]

hi everyone
thanks for the answers!
my new pump was original lycoming (please see attached below)
part no: LW-15473
 
and the new fuel pump is not original lycoming one, part no is: 
AF-15473 High Fuel Pressure Pump
 
So above comments and from the other topics, I understand this is normal unless it’s get crazy..
 
thanks a million for your hep again, I wi update here if anything’s happen..
thanks
seko
 

Give it 20 hours to break in. For those of us with engine monitors that flash warnings when the fuel pressure rises it’s annoying.

[N201MKTurbo]

FWIW, I talked to the principal engineer for the RSA5 and he said that the servo will work just fine with an inlet pressure of 75PSI.

That doesn't help the folks with the angry engine monitors.

[PT20J]

FWIW, my 2018 factory rebuilt IO-360-A3B6 came with a LW-15473 and fuel pressure is usually around 21 psig in cruise.

[N201MKTurbo]

9 minutes ago, PT20J said:

FWIW, my 2018 factory rebuilt IO-360-A3B6 came with a LW-15473 and fuel pressure is usually around 21 psig in cruise.

Yes, the change seemed to happen just after that.

[sekomel]

hi everyone,

thanks for your help again.

 

@PT20J do you also remember the PSI figures when you were on the ground, especially like first start, like the way I do?

today we measure with manometer in case of any gauge failure etc, the values around 28 to 29 PSIs.

Please see video attached:

 

 

 

[drapo]

I had my IO360 A1A overhauled back in 2019 and I experienced the same issue with fuel pressure around 45psi. I went back to the overhauler to inquire about the problem and he showed me the Lycoming Service Letter L225A which instruct to substitute PN # LW-15473 with PN #62B26931. 

https://www.lycoming.com/sites/default/files/SL255A Approved Diaphragm-Type Fuel Pump.pdf

Fuel pressure is higher but, as shared by M20D0C, the engine manufacturer's specifications calls for such high pressures. 

[PT20J]

I’ve never really paid much attention to it at idle, but I don’t recall it ever getting near 30.

[Ragsf15e]

5 hours ago, PT20J said:

FWIW, my 2018 factory rebuilt IO-360-A3B6 came with a LW-15473 and fuel pressure is usually around 21 psig in cruise.

I got a new pump last year (may) and it sits right at 30psi.  If there was a change, must have been right about 2019.

[PT20J]

Curious if @kortopates has seen this and what Savvy recommends.

Just under 30 is OK, but if it goes over 30 it exceeds a limitation in the AFM. Unless Mooney were to amend the limitation (unlikely since the gauge would have to be replaced and limitation changes require FAA approval) it’s a problem because Mooney, not Lycoming, has the final say. If it were mine, I’d try to find the correct pump and replace it.

Skip

[ArtVandelay]

I got a new pump last year (may) and it sits right at 30psi.

I assume that’s at idle, mine drops to 25-26 during cruise.

[Ragsf15e]

5 hours ago, ArtVandelay said:

I assume that’s at idle, mine drops to 25-26 during cruise.

Yes, idle at 30-31, cruise at 27-29 ish.

[jetdriven]

On 9/1/2021 at 12:28 PM, carusoam said:

Hey Seko!

Have a search around here for the Fuel pressure issues on OH’d engines from Lycoming…

This was a common occurrence a while ago…

Unfortunately, I don’t remember enough detail to point you in the right direction…

I think @jetdriven is familiar with this challenge… (high fuelP in OH’d IO360)

Good luck with your next steps… you are almost there!

Best regards,

-a-

Our fuel pressure is normal, however the oil pressure is 92 psi in cruise and it's been that way for hundreds of hours and it came from the factory that way. Run it.

[Ragsf15e]

20 hours ago, PT20J said:

Curious if @kortopates has seen this and what Savvy recommends.

Just under 30 is OK, but if it goes over 30 it exceeds a limitation in the AFM. Unless Mooney were to amend the limitation (unlikely since the gauge would have to be replaced and limitation changes require FAA approval) it’s a problem because Mooney, not Lycoming, has the final say. If it were mine, I’d try to find the correct pump and replace it.

Skip

I agree about the limitation, but the pump is the correct one.  Apparently the correct pump comes with a stiffer spring now??  

[PT20J]

1 hour ago, Ragsf15e said:

I agree about the limitation, but the pump is the correct one.  Apparently the correct pump comes with a stiffer spring now??  

Well, I’m confused about the LW vs AF versions of the 15473 pump mentioned above and also the 62B26931 version mentioned in the service letter. It seems that Lycoming has more than one fuel pump option.

Evidently people were complaining about this as far back as 2015.

Skip