Fuel pressure sensor one more time

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danno2000
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Fuel pressure sensor one more time

Post by danno2000 »

Just got my 2003 steam-gauge DA40 out of annual and one of the squawk items I had identified was that my fuel pressure gauge on the VM-1000 was consistently reading top-of-scale at 54 psi. Fuel flows were rock solid and engine performance seems unaffected. I'm reasonably confident it's a sensor issue.

Last time, the mechs replaced the sensor, and I got a short period of time when the gauge acted normally. After a while, though, it returned to the constant 54 reading.

This time, they tried replacing the sensor again. My first flight home Saturday it was already back to 54. The mechs had smartly taken a picture of the gauge working during their run-up test the day before - otherwise I would have thought it was basically exactly the same as it had been when I brougth it in. They're gonna talk to their tech-support folks at JPI to see what might be happening here.

I swear I just saw a post on a related issue where somebody learned the hard way that the issue was at some other point in the fuel system, but I couldn't find it via search. Any thoughts appreciated.

thanks,
dan
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astaib
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Re: Fuel pressure sensor one more time

Post by astaib »

Hello Dan,

I don't know if it will help, but when I had issues with sensors of my VM1000 (oil), I found this website: https://vmsupport.weebly.com/
And I discussed with Reggie, who is really an expert of the VM1000 and he is also keeping parts alive and available.

Contact him and ask him, maybe he can help you.

Arnaud.
Arnaud
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Derek
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Re: Fuel pressure sensor one more time

Post by Derek »

I just bought a da40 with the exact (opposite) problem. The fuel pressure reads 0 but fuel flow works as does all other instruments and the engine itself. I read some other posts (do a search on fuel pressure or fuel sender, something like that) that indicate that most often it’s a dirty or loose connection in the wire going to the instrument.
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Karl
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Re: Fuel pressure sensor one more time

Post by Karl »

Sounds like a wiring issue.

Older military gauges used to be designed this way so that a sensor/wiring/gauge failure would show up as a max deflection, whereas a low-pressure reading is definitely a pressure loss not a sensor or wiring failure.
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nathanda40
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Re: Fuel pressure sensor one more time

Post by nathanda40 »

danno2000 wrote:
Mon Oct 04, 2021 1:12 pm
Just got my 2003 steam-gauge DA40 out of annual and one of the squawk items I had identified was that my fuel pressure gauge on the VM-1000 was consistently reading top-of-scale at 54 psi. Fuel flows were rock solid and engine performance seems unaffected. I'm reasonably confident it's a sensor issue.

Last time, the mechs replaced the sensor, and I got a short period of time when the gauge acted normally. After a while, though, it returned to the constant 54 reading.

This time, they tried replacing the sensor again. My first flight home Saturday it was already back to 54. The mechs had smartly taken a picture of the gauge working during their run-up test the day before - otherwise I would have thought it was basically exactly the same as it had been when I brougth it in. They're gonna talk to their tech-support folks at JPI to see what might be happening here.

I swear I just saw a post on a related issue where somebody learned the hard way that the issue was at some other point in the fuel system, but I couldn't find it via search. Any thoughts appreciated.

thanks,
dan
Was this the post you saw? viewtopic.php?p=85942#p85942
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Chrisda40
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Re: Fuel pressure sensor one more time

Post by Chrisda40 »

Dan, I have a G1000, and just last week experienced low fuel pressure reading/alerts. It was a sensor issue. Fuel pressure tested ok with a mechanical pressure test. Mechanic swapped the oil and fuel sensors as, surprisingly, they are the same part. This resolved the issue. He clearly stated that he doesn’t know why this works but in some cases it just does. Go figure.
I do not know if steam gauges in your plane have different sensors than the G 1000.
Also I have a question for you. When we looked at replacing the fuel sensor, the price for the part was $3500 US!!!! Is this price inline with your experience in replacing the sensor in your aircraft?
Regards.
Chris
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Colin
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Re: Fuel pressure sensor one more time

Post by Colin »

Swapping the sensors probably works because they are re-engaging the contacts and those can get loose and stop transmitting.
Colin Summers, PP Multi-Engine IFR, ~2,600hrs
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Diamond_Dan
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Re: Fuel pressure sensor one more time

Post by Diamond_Dan »

Colin wrote:
Sat Oct 23, 2021 11:33 pm
Swapping the sensors probably works because they are re-engaging the contacts and those can get loose and stop transmitting.
Colin - I think it is more than that. I was having false low fuel pressure alerts (G1000) and re-seated the connector several times which did not fix the problem. Not until physically removing the sensor, blowing out the orifice with compressed air, and flushing out the fuel dead-leg did the problem go away.
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