Your problem could be either worn points or more likely, the points are not
adjusted properly. When the points are connected and power goes to the pump
coil, the diaphram is pulled by a long rod connected at the center to fill
the valve chambers with gas. When it reaches the end of it's travel it
pushes against the points mechanism which flips the points open. The power
to the coil is gone and the diaphram is released to push gas out against the
reed type valves on the inlet. At the end of this travel the points flip
back to the on position. After a bit of pumping the diaphram does not return
all of the way because the gas has nowhere to go. The line is presurised.
When mine died the same way yours did I just replaced it with a new one.
After about two months I had the same problem. The problem was that as these
pumps get old the diaphram either shrinks or is not as flexible. Both pumps
would pull on the diaphram to fill the valve chamber but did not pull the
rod far enough to flip the points back off. Hitting the pump helps it to
reset the points and the pump works until it hangs again in the same
position. You can adjust the points by unscrewing the flange like section of
the pump where the diaphram is and once appart, rotate the diaphram to
uncrew it a bit from the points mechanism. In my case, I only had to free
the diaphram from the mating surface. I could see that it was really
stretched across the mating surface. There is a bit of play available with
the hole alignment and I was able to just reassemble the flange with the
diaphram no longer stretched accross the mating surface.
New pumps have probably been sitting on someone's shelf for 10 years or were
not adjusted properly at the factory so I would check it before I installed
a new one. Try to fix your old one. This can be not only frustrating and
embarrasing but really dangerous. Mine liked to die right before I hit the
gas to make that left turn in front of an oncomming truck. Fix it right away
before you get hurt.
Chris Reichle
----------
From: mgs-owner
To: mgs
Subject: More fuel pump questions...
Date: Tuesday,September 10,1996 12:08AM
Okay, I know I already went through this, but I got a variety of
responses last time... I have a bit more info to provide to narrow this
down, now, too.
As you may recall, I have an intermittent fuel pump...I think.
Here's the sequence of events:
1) I get the car, drive it about 500 miles, it quits on the
highway. No response from the throttle (no "glug, glug" associated with
ignition problems as you press the accelerator); ignition light on. Try to
start it a few times; turns over, won't fire. Wait a few minutes, try
again, and it runs fine.
2) 500 miles later, same thing happens, but this time, I'm stuck
for about an hour. A couple times during this episode, it sputtered, but
didn't run. Finally, it started and ran fine.
3) 700 miles later, same thing. As soon as I get it to the side of
the road, it fires up. Drive about 2 miles, and it "boggs down" ie.
pressing the pedal results in a deep groan, and VERY little power. Mind
you, the engine is still running, but like it is being choked - literally
<g>. Then, all of a sudden, I'm back to normal power. The car never quit
running altogether. A few more miles down the road, it did quit. Tapping
the fuel pump a bit with the tyre iron fixed the situation, or seemed to
anyway.
It's been another hundred miles or so now, and all is well. I guess
I just want to confirm with this new information that it is, in fact, the
fuel pump before I go buying a new one. By the way, has anyone had any
experience with one of those "double-ended" fuel pumps? Are they worth the
extra cash?
Thanks for your patience,
J
________________________
[ JASON DUTT ]
[ simjason@ix.netcom.com ]
\----------------------/
\ 1972 MGB Roadster /
\__________________/
|