June 20, 2014 at 2:07 pm #85178
we’ve spent a lot of time adjusting my 74 414 to get more fuel into both engines during the climb. when I purchased the plane, I noticed about 25-26GPH on climb, and the engines were getting warm as I reached altitude.
Now we can get them up to 30GPH per side, but as I gain altitude the left engine’s fuel flow drops (with mixture levers full forward). By the time I hit 15K feet it’s down to 24GPH and falling. Any ideas on what could be causing this. My mechanic is recommending I take the 414 to a shop that specializes in fuel systems.
BrianJune 20, 2014 at 2:11 pm #105881
Turn the boost pumps on high. That’ll get you another 3-4 gph.June 20, 2014 at 2:15 pm #105882
I had the same thing on my right engine.. turned out to be the fuel regulator was bad.. put a new on in and adjusted the fuel flow according to the SID and it’s good.June 20, 2014 at 3:15 pm #105883
boost pumps on high work great, I get more than enough fuel flow and can pull the mixture lever back to get the desired fuel flow.
The only problem with that is that you get a nasty surprise when you switch to the aux tanks and that engine goes way lean.
will check into the fuel flow regulator, I was guessing there’s something limiting the fuel.June 20, 2014 at 4:31 pm #105884
Did you have any other symptoms of the failed regulator? the other thing I notice is that during cruising, sometimes that side will randomly drop fuel flow by 1-2gph. I can fix it by moving the lever forward, but it only happens on that side.June 21, 2014 at 1:45 am #105896
Yep just like that.. 1-2gph and would end up sometimes with a big split depending on altitude. was getting worse every time I flew it. We tweaked high end 2 times.
The other thing we found was the fuel pressure was also off and needed set back to the standards required for RAM.June 21, 2014 at 2:51 am #105901rwelshParticipantquote :
It is quite easy to screw in the fuel pressure regulator and see how that works. I would loosen the jam nut and do 2 turns clockwise. If that doesn’t help, then you can return it to the original spot and try something else, but I am at a loss on what else to do short of a total fuel system adjustment. But trying to find a shop with the required gauges and tees and expertise may not be easy..August 7, 2014 at 5:15 pm #106737
First replaced the FPR. Improved stability of the system. Before when i was leaning for LOP, I had a hard time because temps were all over the place and the engine would surge some. But at altitude, I was still loosing fuel flow.
Upon further inspection, found a break in the air hose from the turbo to the upper deck of the fuel system. This provides pressure for altitude operations.
after that fix, it’s running perfect. I think both the FPR and air hose needed to be replaced.
now that the left engine is perfect, I think I am going to replace the FPR on the right engine because it’s still a little inconsistent at LOP. I find that the EGT temps can surge up and down 30 degrees at higher altitudes while the left side is now completely solid.
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