'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.

Reply to
KHanawalt
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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.

--

-don

'81 242t '89 744ti

Reply to
don hodgdon

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....

Reply to
Adam Wilner

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.

Reply to
KHanawalt

Will do! Thanks. KennyH

Horsepower is cheaper than therapy.

Reply to
KHanawalt

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.

Reply to
Mike F

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.

Reply to
KHanawalt

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.

Reply to
James Sweet

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.

Reply to
KHanawalt

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.

Reply to
Mike F

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.

Reply to
Rojo2G

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