Help, 1970 250c stalling

[magnumrick]

My always reliable W114 250c died on me several times yesterday. A couple of weeks ago the car cut out while driving, but restarted and seemed to work fine. We had had some rain so I thought maybe it was water in the fuel so I added gas dryer and everything seemed OK. Yesterday I stopped for gas and when I went to leave the station the car died. I added another bottle of gas dryer and after a few minutes was able to get it running and then it died a block later, of course in an intersection. A few minutes later started up and took me about a mile and died again. Added more dryer and limped it home with several more stops along the way. I checked the gas filter and it was clear and full of fuel.(the car has webers) I'm wondering now if it might be electrical? Could it be the coil? The car also has a CRANE system. Logically everything points to a fuel problem but the car does not studder or cough when it dies it just cuts out. While I'm rolling to a stop I noticed that if the car is still in gear the alternator light is off till I push in the clutch so I know the ignition is still on. Any one have any ideas?

[JimFreeh]

We had this same problem with our 250C.

Turned out to be a plugged fuel filter.

Jim

[250 Coupe]

Mine was a plugged filter also.

There may be a filter as part of the fuel pump. If there is a bolt in the center of the dome on the fuel pump, you have an internal filter.

Michael

[ctaylor738]

There's a strainer in the tank that could be plugged.

And if you have one of the really old fuel pumps with the bolts that hold the two halves together, there's a brass filter in the inlet.

[magnumrick]

Thanks for the quick response. I will check the fuel pump tonight to see if it has a strainer. I'm more inclined to think it is the tank strainer just because of the timing of the fillup. Can I access the tank strainer from in the trunk? Does it require any special tools? Do I need to drain the tank? Just as a point of information, what symptoms does a bad coil give?

[ctaylor738]

You access the strainer from under the car. You do need to drain the tank. You need a giant hex key to get it out. If you do a search, you will see how others (inlcuding myself) have improvised tools to remove it. I used a combination of a 13/16 spark plug socket, a 5/8 sparkplug socket and a 5/8 joining nut, then a 5/8 socket on my ratchet.

It's a terrible job on your back.

[Blue 72 250]

Not to mention that it poses a little excitement and danger. Be sure to do the work outside. I would recommend buying a fuel filter with a replaceable screen unit. I have the rust issues which causes me to replace the filter about every 5 tanks. That way I can clean it on the side of the road and I am good to go. One thing to note: I think that a plugged filter after the pump will cause an increase in pressure at the pump diaphragm resulting in a premature pump failure. It may be possible to place the filter before the pump.

[barry123400]

As soon as it quits if you get out open the hood and pull on the linkage. See the acellorator pumps squirt? You have fuel. No squirt no fuel. You may have to drive around with it a little or let it idle in your driveway. Until it quits.
Best way I can think of to eliminate fuel from electrical on this model. Oops maybe webers do not have a visable gas stream on their accelorator pumps. You may have to look. I wonder why I was thinking zeniths when I started this?

[magnumrick]

Thanks again for all the great info. I happen to have a 7/8" allen so will pump out the tank and clean up or replace the strainer.

[JimFreeh]

It's a lot easier to replace the line filter than clean the tank strainer.

Do the easy fix first.

Jim

[ggenovez]

I ran into a similar problem a few months back.

I would be driving on the highway without a problem get off and the first stop she would stall. Tried raising the RPM. nothing. Would also occasionally stall or try to when I would start from a dead stop. Turned out to be the manifold gasket.

I would bring the idle down to under 700 and start spring the vac lines, around those wonderful Zenith carbs (never change them. they run great), the intake manifold... and listen for any changes in RPM.

If you hear anything that's where your leak is.

Another thing you can probably check is the vacuum you should be close to 17 " on each of the carbs at idle (under 800 RPM)

[magnumrick]

Last week I finally drained the tank and replaced the strainer. The original looked clean but I put the new one in any way and also replaced the small filter by the carbs. I also replaced the plugs and checked the cap, rotor, etc. Yesterday I filled the tank with premium and drove to work without any issues. When I left work in the afternoon I had a stop to make and when I got back into the car it started right up and then cut out and died as soon as I got into the street. There was no studdering or anything, it just died while driving. After about 5 minutes with the hood open and many tries it started up and no more problems. This morning I drove it to work with several stops and no problems. I can't wait to see how my ride home is going to be. Any ideas? The car has webers and a Crane ignition unit. Could it be the coil, fuel pump?

[barry123400]

Pull on the linkage when the car is capable of running. If you see a spray on the webbers do the same test as soon as it quits. You will then know if it is fuel or electrical. You may have already saved the filter job if you had checked. I do not know if it is fuel or electrical at this point.
Another easy check to differentiate between the two is to tape a neon bulb to one of the plug wires. It should light with each firing pulse. In fact leave it on for future refference . A 69c part if you cannot find one free. Or sometimes found in cheap household electrical testers. No connection to the ignition wire is required just in close proximity.
If the engine quits just look at the neon to see if spark is still present when cranking. You may find the second test easier to perform.
Another quick test is to spray some flamable liquid into the carbs as soon as engine quits. If it instantly restarts you again know it's fuel related even if it quits again right away. I could go on and on but when I was a young fellow with little experience I had to develop simple tests. Tests beat guessing and wasting time hands down almost everytime.

[Blue 72 250]

I vote for an intermitant electrical connection. Look for frayed or loose wires. I doubt that the coil is the problem. There is never any shame in cleaning out fuel filters on old cars.

[JMela]

Sounds electrical - dirty ignition switch perhaps?