Bosch fuel pump question

[oldbike54]

 The fuel pump on the Jackal occasionally (like every 20K miles) decides it wants to go on vacation . The first time Rodekyll advised a good internal cleaning wouldn't hurt , and voila , the pump worked fine for another 20K . It acted up again at CV , a quick tap on the pump brought it to life , and we made it the 150 miles home before it decided to take a break . This time it was a bit more stubborn , in fact to the point where I began to believe after 130K miles maybe it was tired . Being the frugal Guzzi owner (read as impossibly cheap ) I just couldn't give up W/O one more attempt . Carb cleaner , a blast of 40PSI air , and the pump seems to be fine again , started multiple times , runs fine .

 Here is the question , there seems to be a ball valve in the output side , could see something moving and once it did the pump works fine . Anyone have an idea , or a blow up pic of the internals ? Delrod and I have decided we may have to dissect one to have a look see , but being a good Guzzi owner precludes cutting up a working pump 

 Dusty

[rodekyll]

I'll ship you a dead one, but you have to have someone film you cutting it open.     Once they get to the point that you have to persuade them to cooperate, not unlike a woman, it's time to move on.

otherwise -- the pump is fitted to about everything coming out of the EU and a lot of other places.  It's on ebay in a couple-three versions, depending on the spigots you need.  I replaced mine with a bosch clone for about $40 and it works like it ought to.

http://www.ebay.com/sch/i.html?_odkw=bosch+inline+pump&_sop=15&_osacat=0&_from=R40&_trksid=p2045573.m570.l1312.R1.TR0.TRC0.A0.H0.TRS1&_nkw=bosch+inline+pump&_sacat=0

[Kiwi_Roy]

This document shows one on page 6
The pump is at the RH end, it pumps the fuel thru the motor and if the filter should happen to plug it will relieve back thru the hollow armature at about 75 PSI

http://www.dpguzzi.com/efiman.pdf

[CalVin2007]

  Yep, Roy has it right of course. When I heard a light tap got it going again at Cedar Vale I thought "worn out brushes". Still thinking so....cut 'er open and have a look! 

[fotoguzzi]

Dusty, I have one in my pile marked "bad" I'll send to you to cut up or try to get working as a spare. pm address.

[oldbike54]

 The bike always runs fine after getting started , the pump just seems to get a bit of grit in it and can't get going from stopped . The filter is downstream , and is only a few months old . Maybe when I return from Arkansas a tank flush would be in line .

 Thanks for the offers , will send out an address later .

 Dusty

[Maximzodal]

Did anyone ever dissect the fuel pump?

[oldbike54]

 Dang , had forgotten all about this thread . Yeah , cut it apart , it probably could be repaired if the internals were accessible W/O butchering the pump .

 Dusty

[RinkRat II]

 Thank you very much Roy for that drawing! Answers a few questions I had about the internals of the secret parts....

        Paul B

[n3303j]

Got caught up with the EFI manual that was linked in this post.
I recently junked the canisters on my EV and replaced tired hoses.
There is one spigot on my regulator that was ported to open air. Called a MG mechanic and he said the spigot was unused.
Looking at the diagram (pg 3, yellow circuit) that regulator spigot is connected to vacuum taps near the butterflies and is used to keep a constant ratio between fuel pressure and manifold pressure.
So now I wonder if I should create this regulator/manifold hookup. I think the taps at the butterfly were appropriated for the carbon canister system.
Would this regulator/manifold circuit assembly aid performance or economy?

[guzzisteve]

I'd leave it alone.

[rodekyll]

There is no relationship between fuel pressure and engine vacuum, except that without the one, you don't get the other.

[n3303j]

There is no relationship between fuel pressure and engine vacuum, except that without the one, you don't get the other.

The circuit illustrated in the EFI manual would establish a relationship between fuel delivery pressure and  manifold vacuum because it is applying a varable vacuum at the back of the regulator diaphram. In effect it would lower fuel delivery pressure (hence volume) in instances of high vacuum.
Rolling off the throttle closes the butterfly and the vacuum goes up. You want less fuel delivered when rolling off the throttle. Reducing pressure at the injector would reduce fuel delivered. Looks like the vacuum line setup in the EFI manual is designed to accomplish this end.
The BMW K100 used a microswitch to shut off the injectors at full closed throttle. It was over ridden by the computer as RPM dropped below 2K or so RPM. The exhaust didn't burble or pop on heavy deceleration. The K75 didn't use this setup and would pop on hard deceleration.
Maybe the vacuum applied to the back of the regulator is Moto Guzzi's attempt to accomplish this same fuel modulation?

[rodekyll]

The book is wrong.

[n3303j]

The book is wrong.

A rather cryptic statement that does little to provide any useful information (sorry).

Do you mean the fuel injection circuit diagram does not match the production vehicle?
Or maybe it does match the production vehicle but the configuration provides no benefit?
Or maybe the book is not an official Moto Guzzi document and has no relationship to Guzzi reality?

Enquiring minds want to know.

[rodekyll]

Nothing cryptic about it.  The book shows a hose where there is none.  What book it is doesn't matter.  The only stretch I can make on the diagram is that it shows a hose going to the airbox, still open to atmosphere, which is not the case with the Jackal-era cali's.  The spigot is not connected to the vacuum ports on the manifolds.  And even if it was, the manifold vacuum goes to the carbon cans, which are a metered vacuum leak.  So in OEM configuration, there's still no control vacuum present there.

Like I said in my first post, fuel pressure is a constant.  It doesn't adjust for conditions.  Fueling is controlled by the ecu's timing and duration of the injector pulse.  Over or underpressure the fuel rail and you'll have issues.

But go ahead and do what you will.  You can't damage anything except maybe the regulator diaphragm, and you can always return the spigot plumbing to unmolested condition.

[Chuck in Indiana]

Or maybe the book is not an official Moto Guzzi document and has no relationship to Guzzi reality?

Many times, the official MG document has no relationship to reality.
It's *not* like an aircraft manual..  It's been cut (with scissors) and pasted (white glue) since forever. It may or may not apply. Use caution when slavishly following "the book" with Guzzi manuals.