Fuel pump problems 1992 740 wagon. Help needed?

I'm at a loss what to do. I've got a 92 Volvo 740 wagon. My
repairman (not a Volvo man) replaced the fuel pump 5 weeks ago. Two
days later, the car wouldn't start and had to be towed back. He
claimed the pump was defective and replaced it. The day after I took it
home, the car stalled about 3 blocks from my house and had to be towed
again. The repairman claimed the hose to or from the fuel pump was
leaking. In the three weeks since then, the car has stalled out about
every 3rd or 4th day while driving. It's failed to start once after
filling with gas and this morning, stalled at a stop sign. In all of
these cases, I've been able to re-start it.

Does anyone have any idea what may be wrong? I have a sense my mechanic
doesn't have a clue. Each time he's taken it in to replace the
pump, it's taken at least three days to get a new pump and replace
it. MY 16 year-old son is learning to drive with this car and is
already complaining that I should get a new one.

 

It could be that the in-tank pre-pump is clogged or failed. That will
burn out the main pump. You really need a mechanic who knows what they
are doing with Volvos. The worst thing you can do with these cars is to
expect a general purpose mechanic to get things right. You need someone
who spends their days working on European cars with a heavy dose of Volvos.

John

 

Has he replaced or resoldered the fuel pump relay? That's the usual
cause of this problem, the pumps normally last at least 150K and usually
longer, I've never heard of a new one being bad.

I agree with the other person who replied, find a Volvo specialist,
these are good solid cars and not difficult to work on but they're quite
different from the typical domestic or Japanese car, you need someone
familiar with European stuff if not Volvos in specific.

 

_____
I concur. In-tank pump failure is likely. Electrical circuit is
usually ok, but do check fuses and tachimetric relay as well. If
in-tank pump fails or does not deliver enough fuel to main pump, then
main pump will _not_ provide enough pressure at fuel pressure regulator
at the fuel rail. Pressure spec is about 50 - 65 psig for LH-jetronic
injection. Easy to check. Replacing in-tank pump is not difficult.
See FCP Groton LLC for parts.

 

Not so sure about the Groton in-tank pumps. I just installed one on our
'93 240 and it is very noisy. I don't like that it was an unbranded
part in a clear plastic bag without even a country of origin. Come to
think of it, I think that US law requires everything to be labeled with
country of origin.

John

 

I'm pretty good with a soldering iron. Is it easy to find and re-solder
the relay?

 

Yeah it's in the fuse panel, in my '87 that's behind the ash tray under
the radio, I'm not sure if a '92 is the same.

Resoldering it is a simple matter of popping the cover off and flowing a
bit of fresh solder on the big joints, it'll be obvious when you get in it.

 

Another possibility, that a good Volvo mechanic would be aware of, is
the rpm sensor mounted on top of the bell housing. When they go
'blinky', they will cause the problems that you describe.

The ECU has to have a signal from the rpm sensor, before it will turn
on the fuel pumps. No signal, no pumps.

 

Good point.

Sometimes the sensor is OK, but the connection to the wiring harness
gets dirty.

Plug and unplug the connection (near firewall, at end of sensor wire) a
few times.

You never know...