Volvo Maintenance Hints for 7xx/9xx - Bill Garland's Nuclear ...

Noisy Fuel Pump: FPR Faulty. [Tip from Jeff] I have been fighting a noisy fuel pump, rough
idling, and poor performance for the past 3 months and finally solved the problem. It may not be
a faulty fuel pump. In my case it was not. I replaced pump and the new one was just as noisy. I
checked the in-tank pump and it worked fine. Then I disconnected the outlet or return line from
fuel pressure regulator and attached a piece of fuel line to it and stuck it in a bucket. Nothing
came out with engine running. The fuel should have been gushing out. I replaced the regulator
and I have a totally new car. It runs like a top with no pump noise. So before ruling out pump
problems check the regulator output first it is easy and takes about 3 minutes to test.
Fuel Pressure Test Tool. See the FAQ file for a description. See also the above notes from Art
Benstein, who used a tire gauge to test his system.
Failed Check Valve. [Symptom:] My '84 244GLE is equipped with
B23F engine and LH Jetronic 2 fuel injection, she doesn't want to
start (read run) the first time -though cranks fine- when it has been
sitting at least 6 hours. The car will start without hesitation on the
second try. [Diagnosis:] It sounds like a classic case of failed fuel Fuel Pump Check Valve
pump check valve, on the main pump under the car, left side,
beneath the driver's seat (in LHD cars). The check valve keeps
the fuel rail under pressure after shutting down. Under pressure
the fuel cannot vaporize and cause a "vapor lock". This will
usually only happen under very hot conditions. On fuel injected
cars vapor in the line would only delay a start, not prevent it. The
check valve also allows fuel pressure to build faster resulting in faster starts. They cost about
$14 at the dealer and are fairly easy to install. Just go buy one at the dealer and they'll show
you in the parts book where it goes.
Volvo Maintenance FAQ for 7xx/9xx/90
Cars Top of Page