'81 240 won't start

I just picked up an '81 240, and it's been sitting for three years. He parked
it when it started having an intermittent starting problem.

I turns over, then catches as if it's going to start, but only idles roughly
for a second or two before it dies. Immediate attempts to restart don't even
cause it to try and start, but waiting 10 or 15 seconds will cause it to try
and start, stumble and die. I can hear the fuel pump running for a few seconds
after it dies.

I've heard about this 25-amp fuse. The one in the fuse block looks okay, but I
read somewhere about one under the hood, but I can't find it.

KennyH

Horsepower is cheaper than therapy.

 

Is your '81 a K-jet? If so, it won't have the 25-amp fuse under the hood.

Check the fuses for corrosion and check your fuel pump relay.

 

Check for vacuum hoses that may have come off under the hood or that may
have dried out and cracked, very often this occurred on our older 240 series
and in a matter of seconds was repaired and car was running flawlessly....

 

Is your '81 a K-jet? If so, it won't have the 25-amp fuse under the hood.

Right. I discovered this belatedly.

I did that, and in fact removed the fuel filter to replace it, but the elbow
won't come out. It broke the brass threads loose and just spins in the old
filter. I'll have to find a new elbow--actually, I'm planning on installing a
T-fitting so I can easily do a pressure check.

While the filter was off, I ran the starter to see if both pumps were doing
anything, and the in-tank pump won't move any fuel, but the main pump really
moves a bunch.
At first the fuel is clear, but then becomes aerated, with lots of bubbles. I
don't know if this is normal when there's no restriction to build pressure. If
not, there may be a hole upstream of the pump that pulls air in.

Thanks!

KennyH

Horsepower is cheaper than therapy.

 

Check for vacuum hoses that may have come off under the hood or that may

Will do! Thanks.
KennyH

Horsepower is cheaper than therapy.

 

There's a hose between the sender and the tank pump. This hose cracks,
and when the fuel level is low and the tank pump is dead, then air gets
sucked into the fuel. Fix the tank pump and hose and the problem will
probably go away. You'll also find the car will probably run fine on
all but the hottest days if you just keep the tank more that half full
without fixing anything.

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

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

 

There's a hose between the sender and the tank pump. This hose cracks,

That makes sense and would explain the symptoms. At first, the fuel in the
line downstream from the pump is not aerated, and it starts and idles just a
couple of seconds, long enough for the aerated fuel to reach the injectors
(fuel being diverted to the tank via the return line allows aerated fuel to
reach injectors quickly) causing it to die. I will definitely check this and
replace the hose. Thanks! Cheaper than a pump.

The in-tank pump is easy to swap, isn't it? I've heard there's an access hatch
on the rear floor, and those pumps are less expensive than the main one. I'm a
little worried about vapor-lock because I live at 5,000 ft. and climbing
mountains creates havoc with vehicles that vapor-lock easily.

Thanks for the info!
KennyH

Horsepower is cheaper than therapy.

 

Yeah it's really not too bad, you remove the access panel, vacuum out the
crud on top of the bung, then remove the nut. You have to get under the car
to disconnect one of the hoses, it's not obvious from looking in the access
hole but there's no coupling you can reach.

 

Today I talked to a Volvo mechanic who said the aeration could be coming from
the tube in the tank that connects the in-tank pump to the fuel line, and if
the tank is less than half full, it can suck air. So I pulled it to the station
and filled that sucker up.

Still no luck, but I did get it running on one cylinder, #1. I pulled the plug
on #2 and it was dry, has good compression, and all plugs are getting spark.

That tells me that the fuel injectors are either plugged or the fuel
distributor is plugged or there's not enough pressure because of a faulty pump.
But then why would the one injector work fine?

I haven't pulled the line off the filter to see if the fuel is still aerated
yet, and if it is, I'll be under the car looking for a cracked line.

I hate to spend the money on a new pump without knowing whether that's the
problem or not. I know I can build a test gauge setup, and may have to resort
to doing that, or I could take the time & money and apply it to installing a
new pump.
KennyH

Horsepower is cheaper than therapy.

 

Keep in mind as you're doing the following that the fuel pressure in
this car is around 70 psi. Be careful where you're directing fuel, have
jars to catch the fuel, and plenty of rags to make sure it doesn't shoot
all over the place.

Remove the injectors from the head, have new outer, thin orings to seal
the injector holders to the head handy, you need to replace them
anyway. (Replacing the fat orings that seal and hold the injectors in
the holders is a good idea at this time.) Pull the hose off that
connects the air flow meter to the air filter. Pull the fuel pump relay
(6 pin relay near the hood release cable handle) and jump the terminals
marked 30 and 87 (on the car harness) which will start the fuel pumps.
Now there should be no fuel coming out of the injectors, but you should
hear fuel rushing in the pipes. Reach in through the hole where the
hose to the air filter was and push up on the air flow sensor plate.
This should start fuel flowing out the injectors, the more you lift the
plate, the more fuel. There will be some resistance to raising the
plate, be careful that you don't bend any of the mechanical linkage. If
you want to see what you're doing, remove the rubber boot between
throttle body and air flow meter. Check the spray pattern and whether
fuel's coming out. If you see no fuel, remove the injector and repeat.

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

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

 

I could take the time & money and apply it to >installing a new pump
I have just finished changing the in-tank pump. I debated to long with myself
about whether to drop the tank. I'm glad I removed the tank to install the
pump. Much better control over dirt etc. and it was only held in place by four
bolts after removing the filler hose which was the most difficult job of
all.While I removed the tank with a jack I installed it by holding it in place
with one hand and setting the bolts with the other. The tank is very light when
empty.