'93 240 won't start

My wife went to work n our 240. She came out at the end of the day and
it spun but wouldn't start. I went there and tried to start it with
the same result. It was raining heavily so we went home.

The next day I went to the car and found the battery dead. The battery
was SEVEN years old so I wasn't surprised to find it didn't work.

Had the car towed to my mechanic. They replaced the battery and then
hooked up their diagnostic stuff. It started. They disconnected their
diagnostic stuff and put everything back in place and no go.

So far they have replaced the crankshaft sensor but now find that the
external fuel pump is getting power and ground and doesn't run.

Ideas?

TIA.

Chuck Fiedler
Nothing but Volvo since 1974

 

If the fuel pump is getting power but isn't running, I'd say the problem is
obvious.

 

O
Hmmmm, I'm going to go out on a limb here.

Tell them to check the fuel pump.

 

So why would it run with the test equipment connected but not without?

 

So why would it run with the test equipment connected but not without?

 

Chuck,

As suggested by other replies:-
Presence or absence of connected diagnostic equipment notwithstanding,
if the main fuel pump is getting proper power (ground and +ve) properly
delivered to its input terminals when it ought to be getting power, but,
is not running, then the main fuel pump has an issue that means it needs
to be substituted, even if only temporarily, before any further
diagnostics can be carried out.

I have to confess to some bafflement as to why with the diagnostic
equipment and new battery connected, the pump runs (it's obviously
getting a 12v supply), but, with diagnostic stuff removed (pump
allegedly still getting a 12v supply when it should), it doesn't run,
that makes no sense at all.

Clutching at straws mode on

Did the garage reinstall your battery as well? Are all the fuses
properly seated and the ends clean, perhaps the new battery they tried
was managing somehow to get a bit more current to the pump during engine
cranking, enabling it to start and run, whereas your battery can't?

Clutching at straws mode off

Best wishes, Ken Phillips

 

Something bad in the wiring harness that the test equipment bridged?
Incorrect reassembly after removing the testing equipment?

 

I just talked to the mechanics. Seems there's an undocumented relay up
behind the glovebox that is fried. This might account for my wife
having smelled something burning (a point I hadn't mentioned here
earlier).

They're waiting for the relay to arrive and will see if that fixes the
problem.

 

Ken, your bafflement is shared.

See my earlier post regarding the discovery of the shop manual
undocumented relay. Methinks we're on the right trail here.

I had previously checked all the fuses, especially the #6. I long ago
replaced those bloody ceramic units with Buss AGPs, glass fuses with
stainless (?) ends. End of the corrosion problems. BTW, I heard those
are no longer available. Go see your local auto store. I got some last
week.

I suspect a Bosch relay is a LOT cheaper than a genuwine Bosch fuel
pump.

Keep tuned to this station for further developments. Film at 11:00.

 

Well now, I just got the car back. Turns out there was a genuwine
Volvo relay, #898151 which was fried. That's the one up behind the
glovebox. The spark coil had also arced somewhere along the way and
needed replaced.

Damages?

1. Relay: $64 plus $63 labor;
2. Spark coil: $81 plus $27 to change it;
3. New 75 month battery: $75
4. Tow in: $91;
5. Two days of trying to figure out what the hell was going on: $267.

All told, I'm satisfied. I sure could never have figured that out
myself. To those who responded to my earlier posts, thanks.

Chuck Fiedler
Nothing but Volvo since 1974

 

I question whether the pump was actually recieving 12V *under load* or if
there was simply 12V measured at the wires to the pump with the pump
disconnected. Connect a car battery to a multimeter through a 1 megohm
resistor and you'll measure 12V, but apply any sort of load to it and the
voltage will drop to zero because of the high resistance.

 

Relay is about 50 bucks, or free to resolder which is usually all it needs.
Fuel pump was around $260 last time I bought one.