Manifold Pressure failure

while in cruise flight at 22" MP, my Van's gauge suddenly increased until it hit the stop (and stayed there). Back on the ground, when the master is turned on it immediately increases until it hits stop. I've checked under the panel and there are no loose or chafed wires from the sender to the gauge or ground issues that I can find. Does this failure mode sound like a sender or gauge issue?

I, too, have had trouble with my Van's MP gauge. I'm on my third gauge, and second sender. On my 6, the failure mode starts as intermittant (of course), and sometimes the needle pegs on the high side, and sometimes the low side, then it will correct itself. After awhile (2 -3 months), it becomes permanently bad. I've never found a wiring problem, and have bench tested removed gauges and senders, and they did test bad. Nobody else seems to have a problem with these. Have no idea why my plane eats these. The real cure might be a mechanical gauge.

I have replaced nearly a dozen of these senders on customers planes over the years. Even when they are working I don't like the slow gauge response to throttle position changes they give. A mechanical MP gauge gives instant response and is very reliable.

MP Failure

Monkey, thanks for the input, a mechanical gauge is likely to best solution long term (short term, I'll order another sender).

My MP gage / system worked fine for about 3 months. Then it would peg when I keyed the mike. Or it would peg when I turned on the master. Or stay at zero if I toggled the master.
I replaced the whole system with a mechanical gage and copper tube w/fittings. No issues since.

so sender or gauge?

Hi,

I experience the same issue since yesterday.

On the first flight of the day after 5minutes of flying the needle pegs on the high side, on the second flight the needle pegs the low side. now it stays on the low side, master ON-OFF no needle movement..

May be the sender swallow some fuel due to over priming...?
i've hold the "primer" a little bit more than usual before the engine start of this first flight.

My RV6 got this gauge & sender for the past 10years & 220h.
The 5sec delay on this MP system is not a problem cause i got a fixed pitch,
so the MP is not a 1sec vital info for my use..
I think just replace it by a new one... van's sell's it both gauge & sender together for 84$.

but
Do you think it's more a gauge problem or a sender problem?

Thank's for your ideas

may be the same for you!

After ordering a new gauge/sensor i've install it exactly as the old ones,
and guess what?!

the needle goes to the top! exactly as on the old supposed damaged gauge/sender.

i remove all the stuff trying to find a clue..

i tested my sensor to gauge cable (the 4in1 shielded) and was giving normal results.. just a micro resistance between each sides of wires.. (not all)
it was my clue.. and the solution!

I've changed this white 4 in 1 shielded cable witch is unfindable on most website (A-spruce etc),
to a david clark helmet cable!
This main david clark wire 4in1 is a far better quality wire than the white ones we can find usualy between the sender & gauge.
david clark wire-> 4 in 1 individually shielded, anti-crack rubber cord, with a bonus: the inner wires are black red withe & green.

All is working normally now.
so, it could be good, to change your cable even if it test good,
before buying a new gauge or sender.

Vans Gauges?????

... I am very disappointed in the vans gauges. They look very nice and uniform in the panel and have decent built in lighting. Its to bad it provides a view of my non working gauges much of the time. I have in my airplane alone replaced three fuel gauges, two volt meters, two amp gauges, one manifold pressure, one cht, one egt and am currently in need of three more replacements at annual. The price in a non issue and I for one would be happy to pay four times the price for a little better quality. I really wish Vans would source some high quality units and offer them as well. Thanks, Allan

PerfTech said:

... I am very disappointed in the vans gauges. They look very nice and uniform in the panel and have decent built in lighting. Its to bad it provides a view of my non working gauges much of the time. I have in my airplane alone replaced three fuel gauges, two volt meters, two amp gauges, one manifold pressure, one cht, one egt and am currently in need of three more replacements at annual. The price in a non issue and I for one would be happy to pay four times the price for a little better quality. I really wish Vans would source some high quality units and offer them as well. Thanks, Allan

Click to expand...

Have you dissembled them to evaluate the failure mode? Is it just the vibration?

BillL said:

Have you dissembled them to evaluate the failure mode? Is it just the vibration?

Click to expand...

... No I didn't, but I guess you can't expect much more for the price.