Strange 84 XN6 sedan fuel system problem/coincidence

Steve Leung (sleung@sikorsky.com)
Tue, 30 Jun 1998 10:12:29 -0500

I was chasing down a newly installed noisy in tank priming pump in the
84 505 sedan. I removed it to check if it was wired backwards and it
was not. As a test, I wired it backwards, ran the pump outlet into a
bottle and no fuel came out. I then re-wired the pump correctly,
installed, connect the fuel hoses and the engine wouldn't start
anymore! I checked the power to the priming and main pump and they were
OK. I then took the ring lugs off the main pump, cleaned the contacts
as they looked pretty corroded. Still won't start. I then opened the
fuel inlet at the fuel distributor, cranked the engine and no fuel came
out. So I pulled the main pump off, connect it to 12 volts and it was
stuck! Luckily I had a spare used pump, installed it and car started.
Was this a coincidence? Does strange things like this happen to
Peugeots only? (I've had my share of them believe me) Maybe not. The
previous owner bypassed the in tank pump, replaced it with an electronic
pump (really makes a racket! constant clack clack) outside tank between
main pump and tank, in doing so he replaced the fuel hose between the
tank and the main pump. He also cut the metal fuel outlet of the
priming pump assembly to make it fit the new fuel hose and I think this
is the cause of the problem. The metal burrs of the cut dislodged bits
of fuel hose material that eventually jammed the main pump. Murphy's
law would have it fail at that instant!
There is no filter between the priming pump and the main pump. The
moral of the story is: KEEP IT CLEAN! I've since cleaned the burrs
off. I intend to do a biobsy on the pump and see if my theory is
correct or if this was truly a coincidence.

Steve