[ROVERNET - UK] Loss of power problem again

[Gavin.Walker at csiro.au]

Hi Everyone,
  The loss of power problem in my SD1 has resurfaced.  So far I've done
about 280km on this tank of fuel and I didn't have any hint of the
problem until about 250km.

First showed up again last night.  Running along at 100km/h then power
loss with faint surges that eventually recovered as I slowed down.  At
that point I got stuck behind a car doing 90km and didn't have a problem
for the rest of the night.  Despite another 10-15km.

This morning I get 4 km at 60-80km/h, no problem.  After 30sec at
100km/h I lost power for long enough to have to pull off the road.
After some idling I have a go getting back on the freeway. Get up to
3000rpm in second and lose power again.  The tacho registers about
1000rpm but that's just the torque converter spinning down.  If I hold
the throttle open during power losses it will eventually stall, but if I
stop it will idle contently.

After limping to an exit I was able to drive around at 70km/h for a bit
and then at 60km/h up a hill I loose power again and had to pull over
and idle.  No more problems after than but the rest of the trip is
around campus at 40km/h.

I suspect a failing fuel pump.  I have twin strombergs on my SD1 but the
system has a return line (legacy of a previous EFI setup).  I fitted a
restrictor to the return but it doesn't seem to have solved the
problems.  Next step is clamp off the return line.  The car if fitted
with a repco electric fuel pump (loud) outside the tank and I suspect
that when the tank gets down the pressure differential between the tank
level and the engine is too great and the float bowls slowly wind down.
Idling helpd refill the float bowls and gives a burst of power.

Gavin Walker
1982 SD1
Canberra, Australia