Da40 high fuel pressure/ hot start issue

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JohnLand
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Da40 high fuel pressure/ hot start issue

Post by JohnLand »

My da40 recently developed an issue where the fuel pressure would spike up significantly right after shut down and if restart is attempted no fuel flow indication despite fuel pump on and mixture rich, and the engine need to sit for 45 ish minutes before the fuel pressure would clear out and Then I can get some fuel flow with the mixture control and restarts ok.

Wanted to check and see if anyone else have encountered similar issues.
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danno2000
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Re: Da40 high fuel pressure/ hot start issue

Post by danno2000 »

Yes, I had the same thing happen to me a few weeks ago - flew for an hour and a half, landed for fuel, after fueling, tried to restart and got no fuel flow indication. Almost called my wife to pick me up from two hours away before it finally cooled down enough and I got fuel flow.

Then a week ago, on another hot start, I got no fuel flow. Thought I'd have to wait for it to cool, but it turned out I could use the normal hot-start procedure. Concluded that I probably flooded the engine the first time.

I'll be doing another trip tomorrow where I fuel at an intermediate stop. The uncertainty's enough that I'm getting to the point where I'm tempted just to always fuel at home base even with higher prices.

best,
dan
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Scottsware
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Re: Da40 high fuel pressure/ hot start issue

Post by Scottsware »

Hi John,

You said you had the fuel pump on and mixture rich. Did you also open the throttle wide open when trying to get the fuel flow going (as indicated on the fuel pressure gauge)? I figure you would have done that but I didn’t see it in your text. It sounds like you had some wicked vapor lock. I’ve had that when it’s hot but full throttle, full mixture and fuel pump on has always worked to push through the locks so I could then do a flooded start.

Scott
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pietromarx
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Re: Da40 high fuel pressure/ hot start issue

Post by pietromarx »

Warm weather, hot engine, ... ? Sounds much like vapor lock to me and is the reason why I try and always fuel when the engine is cold or when I have time after fueling before flying. My old DA-40 didn't have the issue as badly as my current one.
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Steve
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Re: Da40 high fuel pressure/ hot start issue

Post by Steve »

Also sounds like vapor lock to me. I'll refer you to a previous thread:

viewtopic.php?f=8&t=4102&p=43728&hilit=oil+door#p43728

Steve
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