Paul,
Thanks! I remember your problem from a few years back. As a matter of
fact I had suggested a fix (drill a vent hole in your fuel cap). If you
look back through the e mail you received, you'll see one from me.
In my case I have a high compression ~9.4:1, with a Piper fast road 270
cam, ported head, HIF4's and ABD needles.
I am running a Lucas replacement distributor intended for the early high
compression engines. My rear HIF carb has been drilled to provide ported
vacuum.
All was great until my pump points deteriorated. Although the pump still
pumped and tested ok, it's output at higher RPM's had deteriorated due to
the burnt points. At idle and low speed cruise, the problem did not occur.
Since the MGB manuals do not list a suggested maintenance schedule for fuel
pump points, I thought I would pass along my findings.
John
----- Original Message -----
From: <ptegler@cablespeed.com>
To: "John Di Fede" <difejo@optonline.net>; "MG Mail List"
<mgs@autox.team.net>
Sent: Monday, July 12, 2004 8:59 AM
Subject: Re: SU Fuel Pump Tip
> If you've been/were experiencing a 'stumble at cruise'
> I'll bet you'll start noticing it again shortly. The flaky points
> can and will be the cause of many cars stopping with
> the driver having no clue as to the problem, but I'll lay
> odds of dollars to donuts, the pump was/is not the
> only problem causing an oscillation at cruise. btdt.
> http://www.teglerizer.com/mgstuff/a_stumble_at_cruise.htm
>
> Paul Tegler
> ptegler@cablespeed.com
> www.teglerizer.com
> ----- Original Message -----
> From: "John Di Fede" <difejo@optonline.net>
> To: "MG Mail List" <mgs@autox.team.net>
> Sent: Monday, July 12, 2004 2:03 PM
> Subject: SU Fuel Pump Tip
>
>
> > To all;
> >
> > I normally lurk on this list.
> >
> > I recently uncovered a problem with the SU fuel pump on my 1973 MGB.
This
> tip may be helpful to someone experiencing a similar problem.
> >
> > My MGB would lose power and stumble between 3500-4500 rpms. I tried new
> plugs and wires, ignition timing, carb tuning and checked for an intake
> manifold leak. All with no success.
> >
> > I tested my fuel pump by disconnecting the fuel hose to the carbs, and
the
> pump conformed to the test specs I had. It was able to pump 1 pint in 15
> seconds.
> >
> > So, I am out on a drive and all of a sudden my car dies, and I realize
> that I cannot hear the SU pump tic, tic, tic. I rapped the pump and it
> started working and I was able to get home.
> >
> > Once home, I removed the pump and discovered the points were in bad
shape.
> Replaced the points, and my loss of power problem disappeared.
> >
> > So my conclusions are that a pump can test ok, but not be able to keep
up
> adequate fuel pressure as RPM's increase, and that from now on I will be
> replacing the fuel pump points as a matter of routine maintenance.
> >
> > BTW, this was a SU pump about 8 years old with 17k miles of use and
always
> garaged.
> >
> > I hope this tip helps.
> >
> >
> > John Di Fede
> > Hopewell Junction, NY 12533
> > difejo@optonline.net
> >
> > 1973 MGB
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