Today's Message Index:
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1. 07:45 AM - Re: 3300 - low oil pressure at high RPM (Roger Lee)
2. 12:44 PM - Re: Re: 3300 - low oil pressure at high RPM (Kayberg@aol.com)
3. 10:22 PM - Re: 3300 - low oil pressure at high RPM (Roger Lee)
Message 1
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| Subject: | Re: 3300 - low oil pressure at high RPM |
Having a low oil level will cause this because many oils will foam, then you start
pump in some air and this reeks havoc on a sender and your internal parts.
Some are more prone to foaming than others. If you use an electrical oil pressure
sender then yes a poor ground can cause this. These are a resister type and
very sensitive to poor grounding. I deal with this a lot in Flight Design CT's.
If it were a mechanical type gauge with actual oil in it then no it wouldn't
be the cause. Oil pressure senders are notorious for going bad. Like the Rotax,
it uses a VDO oil pressure sender and they do go bad. If the pressure goes
down on throttling up and then back up when throttle is reduced look definitely
at the ground. If the gauge pegs out at the max look at the ground. If it
drops to very low like 15-20 psi then most likely a sender or gauge, but I agree
that in flight a quick cross checking to make sure it really is a sender and
not a real low pressure issue is extremely prudent and I wouldn't fly it until
I had a handle on the problem. The only sure way to check these is on the
ground. Tie the plane down so you can run up the rpm. Put a mechanical gauge setup
in line with the electronic sender and run the engine. Make sure that they
read the same. 98% of the time when I do it this way the real engine oil pressure
is ok and I find it is just the sender or the ground. So use good diagnostics
on the ground and find the problem in an a to b to c to d logical diagnostic
pattern.
p.s.
The sender or the gauge may have the poor ground.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Repair Center
520-574-1080
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=313374#313374
Message 2
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| Subject: | Re: 3300 - low oil pressure at high RPM |
A Jabiru is not a Rotax by any stretch. Hence Rotax experience has little
value here.
A Jabiru will run on half a cup of oil, the Rotax will not.
Actually, the Jabiru will do the oil pressure and temperature dance if it
has too MUCH oil! They do not like being even slightly overfilled.
That being said, I do not have a lot of faith in VDO senders. So I would
agree with your suggestion of a temporary mechanical guage!!
Doug Koenigsberg
In a message dated 9/22/2010 10:45:51 A.M. Eastern Daylight Time,
ssadiver1@yahoo.com writes:
Having a low oil level will cause this because many oils will foam, then
you start pump in some air and this reeks havoc on a sender and your
internal parts. Some are more prone to foaming than others. If you use an
electrical oil pressure sender then yes a poor ground can cause this. These are
a
resister type and very sensitive to poor grounding. I deal with this a lot
in Flight Design CT's. If it were a mechanical type gauge with actual oil in
it then no it wouldn't be the cause. Oil pressure senders are notorious for
going bad. Like the Rotax, it uses a VDO oil pressure sender and they do
go bad. If the pressure goes down on throttling up and then back up when
throttle is reduced look definitely at the ground. If the gauge pegs out at
the max look at the ground. If it drops to very low like 15-20 psi then most
likely a sender or gauge, but I agree that in flight a quick cross checking
to make sure it really is a sender and not a real low pressure issue is
extremely pruden!
t and I wouldn't fly it until I had a handle on the problem. The only sure
way to check these is on the ground. Tie the plane down so you can run up
the rpm. Put a mechanical gauge setup in line with the electronic sender
and run the engine. Make sure that they read the same. 98% of the time when I
do it this way the real engine oil pressure is ok and I find it is just
the sender or the ground. So use good diagnostics on the ground and find the
problem in an a to b to c to d logical diagnostic pattern.
p.s.
The sender or the gauge may have the poor ground.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Repair Center
520-574-1080
Message 3
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| Subject: | Re: 3300 - low oil pressure at high RPM |
Hi Doug,
I agree whole heartedly, a Jabiru is not a Rotax, but the gauges, sensors, senders
and wire hook ups share many commonalities in wiring and they are the same
company in many cases and have the same issues. The specific engine doesn't
really matter.
The exact same rational can be used in different make cars. They are very different,
but share electrical needs and wiring with the same principles.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Repair Center
520-574-1080
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=313458#313458
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