Metal in the fuel pump now?!!

Like a bad dream from which I cannot awake, I just received yet some more
bad news.

The new engine-driven fuel pump of my Bonanza's rebuilt IO-520 engine was
having trouble maintaining proper fuel pressure at low throttle. The
company that is responsible for the pump and fuel system wanted the pump
back so that they could tear it down and see what was causing the
inconsistent pressure.

Well, today they found the problem: Metal in the pump, presumably coming
from somewhere upstream. Furthermore, they now want the injectors back
because the metal has most likely contaminated these, too.

My local mechanics have now started the investigation that, no doubt, will
yield some major work to correct.

Anyone ever encounter this before? Now what am I in for?

--
Peter
That, which does not kill you, only serves to make you stronger... and
poorer.












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Are you positive it's metal? There is a service bulletin on the Dukes
electric
fuel pumps to replace vanes with Nitralon ones. They were breaking and
gumming up things downstream.

Do you get the pressure with the electric pump that you should?

It's hard to imagine how metal could get into the fuel pump. There is
a seal between
where the oil is and where the fuel is. When it fails, the ususal
problem is fuel leaking
OUT.

Could the fuel pump be destroying itself? There is a very fine screen
in the
distributor on top of the engine... that is where the metal would be.
I can't imagine
how it would get into the injectors.

Bill Hale BPPP Instructor

Well, today they found the problem: Metal in the pump, presumably
coming from somewhere upstream.

Or from the pump itself. Of course the pump manufacturer isn't going
to tell you THAT.

Furthermore, they now want the injectors back
because the metal has most likely contaminated these, too.

If the injectors are contamined, so is the fuel servo and spider. They
will have to come off.

Michael

" wrote:

Are you positive it's metal?

Positive. This is a newly rebuilt engine from Tornado Alley. The engine
is rebuilt by one individual, whereas the fuel system is built up by
another, then sent to the engine rebuilder for installation and setup.

My local mechanics installed the engine and have been working with me to
get it running optimally. Over several test flights these past two weeks,
the engine quit on me twice during the landing roll-out. The second time
it happened, the mechanics hooked up a fuel pressure gauge to the system
and monitored fuel pressure while at low throttle. This is when they
discovered inconsistent and abnormally low fuel pressure that resulted in
the engine quitting on them, so they contacted the fuel system company.

The company asked to have the pump removed and sent to them for analysis.
My mechanics complied and had the pump sent overnight. They called today
with their findings that there was metal in the pump that was getting
underneath the relief valve. They stated that the pump was not the source
of the metal, but most likely something upstream was.

Do you get the pressure with the electric pump that you should?

Not at low throttle settings, which is fortunately what tipped off the fuel
system person to want to see the pump.

It's hard to imagine how metal could get into the fuel pump.

This is a rebuilt engine, so there really could be three different reasons
for the metal: 1) Contamination introduced when the engine was initially
run up on the test cell, 2) Contamination introduced during the engine
install, or 3) something upstream, after the fuel filter, eating itself
up.

My mechanics are very trustworthy people and I believe them when they state
that all lines were capped during installation, so I have to discount (2).

Could the fuel pump be destroying itself?

No, as verified by the fuel system company.

There is a very fine screen
in the
distributor on top of the engine... that is where the metal would be.
I can't imagine
how it would get into the injectors.

My mechanic stated that also, but the fuel system company wants to be
absolutely sure of this so they have requested some fuel system parts near
the throttle for investigation.

As a positive note, I spent last Monday night performing a Gami Lean test
with the aircraft, which measures at what fuel flow the cylinders peak (as
measured by EGT). A difference of .5 gallons per hour or less means that
all Gamijectors are working properly. My test yielded a result of 0.4 GPH
between the first and last cylinder peaking, so it appears the injectors
are all healthy. I spoke on the phone with Gami on Tuesday to discuss the
results and they were pleased with them.


--
Peter













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"Peter R." wrote:

They stated that the pump was not the source
of the metal, but most likely something upstream was.

What do you mean by "upstream"? If the metal is in the pumping chambers, then
the problem is in your fuel system. That's at least likely to be less expensive
than the engine.

Sounds to me like someone cut a new line somewhere and failed to clean it before
installation. Just a guess.

George Patterson
He who would distinguish what is true from what is false must have an
adequate understanding of truth and falsehood.

I assume that a Bonanza has an electric boost pump and that there is no
filter between it and the engine driven mechanical pump? I would look at
the boost pump. Sorry to hear about the problem.

Mike
MU-2


"Peter R." wrote in message
...
Like a bad dream from which I cannot awake, I just received yet some more
bad news.

The new engine-driven fuel pump of my Bonanza's rebuilt IO-520 engine was
having trouble maintaining proper fuel pressure at low throttle. The
company that is responsible for the pump and fuel system wanted the pump
back so that they could tear it down and see what was causing the
inconsistent pressure.

Well, today they found the problem: Metal in the pump, presumably coming
from somewhere upstream. Furthermore, they now want the injectors back
because the metal has most likely contaminated these, too.

My local mechanics have now started the investigation that, no doubt, will
yield some major work to correct.

Anyone ever encounter this before? Now what am I in for?

--
Peter
That, which does not kill you, only serves to make you stronger... and
poorer.












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Newsgroups
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Mike Rapoport wrote:

I assume that a Bonanza has an electric boost pump and that there is no
filter between it and the engine driven mechanical pump? I would look at
the boost pump. Sorry to hear about the problem.

Thanks, Mike. The mechanics are flushing the fuel system today and I hope
to hear how that went before the weekend.

--
Peter













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