Hello everyone, I'm new to the forum and know pretty much zip about auto repair. I just bought an '84 240 dl from a friend for like $300. It's got 165,000 miles on it. I deliver pizzas to get me through college, so I need help ASAP! Here's the problem:

-The car began acting like it's running out of gas about one month ago.
-The carused to start fine and idle rough, but now it won't even stay running unless I keep giving it gas.
-While driving, the gas cuts out.The car stays onbut the gas problem has gotten progressively worse over the past few weeks.
-Sometimes it'll only cut out for a second, but other times it'll completely cut out for a few moments. If I give it a bunch of gas it'll usually kick in and get going again. I've been able to "coast" from place to place this way, just to get by.
-The gas almost never cuts out if I'm going fast enough on the highway. But once I get down around 40 mph or so, it'll cut out again.

I've looked around in these forums and have seen a number of potential problems, such as the fuel pump relay, fuel pump, etc...but I wanted to describe my problem more specifically so I can hopefully avoid a bunch of wasted time and money. If someone can guide me through the process I might be able to fix it on my own--I want to avoid spending $$ on a mechanic.

Please help me ASAP if you can! I need to deliver pizzas for $$ tomorrow but I don't know if this car will make it through the weekend...

 

How long ago was the fuel filter replaced? If nobody knows, it's probably due and I would start with that.

It's acting like the in-tank pump or sock filter should be checked out.

Post back.

 

Not sure when the fuel filter was last replaced, so that might be it. Where is that located and how easy is it to replace? Also, what andwhere are the sock filter and in-tank pump? And yeah, I'm aware how stupid these questions all sound...

 

Not sure where the main fuel filter is on the '84. On mine it's under the left side of the car just in front of the rear wheel. The fuel filter and fuel pump are together in a mounting bracket. Earlier 240s had the fuel filter on the firewall in the engine compartment.

The main fuel filter can be tricky because of the banjo bolts. If you change it be sure to use new copper crush washers. It's easy to get a fuel leak.

The sock filter is attached to the in-tank fuel pump and float assembly for the gas gauge -- a pre-pump. It's accessible from the top of the fuel tank through the floor of the trunk. Remove an access plate.

 

Thanks to everyone who's responded so far--I have now replaced the fuel filter and prepump/intank filter, and theinline pump seems to be working fine (if unplugged, I can't give it any gas--if plugged in, the pedal can keep it running if I feather the gas). I alsochecked the fuel pressure regulator "symptoms" suggested above by swederacer, and everything looked fine there. But still, no luck.It still won't stay running without my foot onthe gas, and even then it keeps "missing".

On the advice of a friend, I unplugged the air mass meter to see what would happen. When I started the car with the AMM unplugged, it stayed running (without me having to keep giving it gas) but it repeatedly idled high-then-low-then-high-then-low on its own.

I don't think it's anelectrical problembecause it got progressively worse over the course of a few months, but I don't know what I should check next. Any ideas?

 

Ok so here's an update if anyone can help:

-Both fuel pumps are working and I replaced the fuel filter.
-I recently cleaned a large rat's nest outfrom the air filter.
-The air mass meter is not working properly: when unplugged, the car stays running (but runs rough and sputters when I let off the gas).
-When the air mass meter was switched with a newer (1990-91) one, the car stays running (rough)--but does not run any differently whether the new one is plugged in or not.
-In other words, plugging in my air mass meter causes the car to die, and a newer version does not. However, whether I'm using a new one or just unplugging my old one, the car runs very rough.

-I don't know if I should replace my air mass meter or just leave it unplugged. Replacing it with a newer (but similar) model didn't make it run any differently than just unplugging my old one. Could this be a difference in the type of air mass meter?

-What else could be causing these problems??? Somebody please help!

 

Car is supposed to run with air mass meter unplugged. This puts computer in "limp home mode" It is not supposed to run great unplugged, it is just supposed to get you home or to the dealer.Do not use air mass meter with a different bosch #. If it won't idle then check to see if throttle position sensor just makes an audible click when you close the throttle completely.There are instructions on how to adjust thisswitch if it is not making click in manual or in the garage section.There is a microswitch there to tell the computer to light up the idle air motor. Then there is the idle air motor itself located under the intake. Two rubber hoses, one electrical connection. you can use carb cleaner to clean and I would lightly lubricate. Since you are having trouble idleing start with the idle circuit. If the hose going to the fuel pressure regulator is cracked or has fallen off car will stall at stop lights/ signs.

 

Ok, I still need help, buthere's another update:

-I replaced the air filter (which had a rat's nest in it)and theair mass meter (with the correct model number), and now the car idles relatively okay. There is still a veryslight high-low "shift" in the idle, but it stays runningwithout any problem.
-The car still hesitates when RPMs are low, and often the gas cuts out, usuallywhen the RPMs shift between high and low. The car doesn't evercompletely stall--the gas kicks in after a second or sometimes after afew moments.
-I checked the fuel pressure regulator for any leaks or gas smells (by unhooking the hose), and didn't detect any problems.
-I also checked the air hose coming from the mass meter, and re-taped a small crack that had been sealed a long time ago.
-I replaced all the spark plugs, which were significantly fried. The fourth one had some gas (still wet)on plug.
-The spark plug wires aren't all that great--there is some wear on the wire coating where the clips are--but there is spark on all the plugs.
-The main fuel pump seems to be working, at least in some way(it doesn't work at all if the wires are unplugged) but it doesn't make any noise when the ignition is in the "on" position.
-It is difficult to check for any noises when the car is running, because I need to repair my exhaust (broken near the catalytic converter, loud as hell.)
-Today, I put some fuel injector cleaner in and filled the gas tank.

Anybody have any other ideas? I don't know much about this stuff, but a couplesmartbuddies of mine work on their volvos all the time and still can't figure out what the problem is. I don't think it's electrical because the problem got progressively worse over time, but I could be wrong. Please help--I have a lot offaith in this car if I could just figure out this problem...

 

Just a few more questions/issues (thanks in advance to any help!):

-The fuel pump relay(s): I've found two relays under the passenger side glove compartment (both are about 1" x 1" x 1"...one is white and the other is silver.) The white one clicks when I turn the ignition on, but thesilver one does nothing. If I switch the relays, the silver one clicks but the white one does nothing. If either relay is unplugged when the car is running, the engine dies. So it seems like each relay works fine, at least when it's plugged into one of thesockets but not the other. My question is this: are both relays supposed to click when I turn on the ignition?

-Also, regarding the fuel pump: When I turn the ignition on, the fuel pump does not turn on or make any noise. However, the pump seems to be working when the car is running, because the pedal feeds the engine with gas if the pump's plugged in, and does not if it's unplugged. The pump also seems to make some weird noises when I rev the engine and/or when the RPMs come back down. What could be causing these problems? I've read on these forums that the fuel pump supposedly "works or it doesn't", but it seems like mine is not following this rule...

Any suggestions??? Any quick replies would be GREATLY appreciated... Thanks!