Fuel Accumulator 1981 240DL Wagon

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Hello All,

Am restoring a 1981 Volvo 240DL Wagon. Replaced a failed in-tank pump,
and the main pump under the car. The fuel accumulator sits right next
to the pump. When i installed the new pump i noticed that some fuel
leaked from the vent nipple that is connected to the fuel tank with a
small rubber hose. Am i correct in assuming that the diaphragm in the
accumulator must have a hole in it and that it should be replaced? Or
is it normal to see some fuel at the vent nipple? The system delivery
pressure is steady at 70 psi right after the filter in the engine bay.

Regards / John

 

Yes, time for a new accumulator. There should be no fuel there.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

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Thanks, Mike. I was afraid of that. A friend, who has a DeLorean
sports car with a 6 cyl Volvo engine, gave me his old accumulator. The
engine uses an eCIS, which is virtually identical to mine, but has a
constant idle speed motor and ECU. The accumulator is bigger in
diameter, and a bit longer. I will try that one and assume that the
pressure delivered to the filter will be the same. Once i put the gauge
on it, and i read the 70 psi i get now or higher, i will be happy.

/ John

 

The accumulator is just a "shock absorber" for fuel pump pulses.
Pressure is set by the regulator, and the pumps ability to meet that
pressure. Having an accumulator too big won't hurt anything, having one
too small might, but I doubt it. As long as the fuel connections are
good (don't leak) and you can properly mount it physically (so it's
supported and the fuel lines don't break) then you won't have any
problems.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

The function of the accumulator is to provide enough pressure on the
fuel coming from the pump to force any air bubbles to dissolve in the
fuel and to maintain a small pressurized reservoir of fuel to keep the
lines charged all the way to the injector nozzles so if the car stalls
there is enough residual pressure to allow it to start right back up. If
the weather is very hot it keeps the fuel from boiling in the injector
lines. If the diaphragm is ruptured, i.e. if there there is even a hint
of fuel smell from the rubber pipe that returns to the tank, then the
car most likely will require an extended cranking time to start (but may
start fine) and create no power for a good 60 seconds before you can
pull off, even though the engine seems to react normally to accelerator
pedal pressure.

The newer style accumulators have no vent nipple on the back. A retrofit
requires that the vent tube from the tank be capped or fuel will siphon
out when the tank is filled and the fuel expands while sitting parked in
hot weather.

Bob