Fuel Flow Gage location in the fuel system

[gabez]

Hello, 

I have been dealing with a series of problems with my plane, notoriously the aux tank were not installed properly and the drain plug was not at the lowest point, water accumulated and ultimately messed up the fuel system. We are going to rebuild the fuel pump and flow divider (this has already happened). My question is based on the POH (m20K231) is the fuel gage before or after the fuel divider activates meaning, if the diaphragm doesn't open when fuel pressure is built, would I see flow or not? 

 

thank you

[N201MKTurbo]

I assume you are talking about the fuel flow sensor. Yes, it is before the flow divider, if you had pressure at the flow divider, and it opens, you should see a flow indication. It is hard to imagine a flow divider getting stuck, unless it was horribly corroded. If it was that corroded, you wouldn't be able to rebuild it. 

There is no magic in the flow divider, it is just a manifold. It has a valve that stops the flow when you turn off the fuel pressure. The valve just makes your engine stop better. If you took the valve out of the flow divider, your engine would still run just fine, it just wouldn't shut off right away when you went to idle cutoff.

[gabez]

I had water go through the divider and the pump as I couldn't properly sump the aux tank. Basically I started getting drops of fuel flow on power reductions. We fixed the tanks but now the Flow divider and the pump are out of overhaul. 

We haven't got the parts back yet but the sentiment is that the flow divider maybe getting stuck and opening up on lower power settings. 

 

[N201MKTurbo]

Was the engine stumbling when you reduced power? Fuel flow will go down when you reduce power. If the engine was running rough at lower power, could you fix it with the mixture?

[gabez]

6 hours ago, N201MKTurbo said:

Was the engine stumbling when you reduced power? Fuel flow will go down when you reduce power. If the engine was running rough at lower power, could you fix it with the mixture?

looking at my engine logs see pic below, taking off from Hollister, I leveled the plane at about 2000 feet, backed the power to 30'MP and as you can see from the EGT spike and the FF I went from 19GPH to basically 1, at that point in my flying procedure I am still full mixture in. I then hit the boost (low) and the power come in, I flew a bit and shut the boost off, you can see the second spike, I then turned the boost back on and landed at Watsonville. Both the pump and the flow divider have gone for overhauled and we should have them tomorrow. 

[N201MKTurbo]

2 hours ago, gabez said:

looking at my engine logs see pic below, taking off from Hollister, I leveled the plane at about 2000 feet, backed the power to 30'MP and as you can see from the EGT spike and the FF I went from 19GPH to basically 1, at that point in my flying procedure I am still full mixture in. I then hit the boost (low) and the power come in, I flew a bit and shut the boost off, you can see the second spike, I then turned the boost back on and landed at Watsonville. Both the pump and the flow divider have gone for overhauled and we should have them tomorrow. 

Got it. I would say the pump was your problem, not the divider. But either way you should be good now.

[gabez]

1 hour ago, N201MKTurbo said:

Got it. I would say the pump was your problem, not the divider. But either way you should be good now.

thanks! What type of internal failure would make the pump act that way? just curios