This is the sort of fuel pressure reading we get. This pic is a ‘ground run’.
Care was taken to avoid parallax when this picture was taken.
At FL’s the needle gets ‘in the red’ and the only way to raise it is ‘electric on’ and even then only by a needle thickness.
I don’t like it, but others views are that it’s just a gauge / sender unit problem and therefore ‘no problem’ – monitor it.
I’m also told by others, who have been around longer than me, that the needle has never been ‘in the centre’ of the green arc.
I would have thought in a perfect and brand-new world a needle on any gauge in any industry would be designed / set to mid position for the norm.
What reading do you other PA28 injected guys get, and what do you think of this situation?
Does it make any difference if you turn the aux (electrical) pump ON?
This is with ‘electric on’ and engine running.
I’d say it’s worth finding out why and fixing the problem, even if it turns out really just to be a bad sender. If it’s not guaranteed it’ll actually die just at the wrong time.
A failed fuel pump nearly had me swimming with alligators less than a year ago when it quit at 350 feet leaving New Orleans Lakefront on a southbound departure…
On our PA28R-200, (Arrow II) it still happily in the middle of the green.
If it’s been like that for years, then I’d not panic and refuse to fly immediately, but I would want to get it fixed sooner rather than later. Otherwise the day that there is something wrong with the fuel pressure, how do you know about it (before the engine stops).
Put a calibrated pressure gauge on the line to verify the accuracy of the gauge reading.
I understand the gauge is electrical driven from guess a voltage / current variation generated by the ‘sender unit’. Which in turn is connected direct to the fuel line, thus detecting actual pressure.
On my PA28 that instrument has fuel connected via a copper line. Thus, the instrument is a manometer and not an electrical instrument. Sometimes gunk clogges the tiny hole that leads fuel into the instrument, leading to strange readings.
After clearing the very small hole with a thin sharp object and some parts cleaner, readings were fine again.
G
GaryStorm. That’s very interesting. So our gauge could be electrical OR manometer (direct fuel pressure). Need to check that out.
What year is your PA28 ?
This one was 1973 PA28-180
You could look in the part catalog or another manual, I guess.
G
