Fuel starved?

americium

americium

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In my 69 E3 I have replaced the fuel pump, fuel filter, fuel lines any yet when I drive for an extended period it will start cutting out while driving. I thought I fixed it with aforementioned items but yesterday I took my wife out for a spin and it was cutting out again. (Wife won’t get in it again until I certify it’s fixed). So, on the way back I stopped to get gas and the tank made a whoosh when I took the cap off. I don’t know if it was positive or negative pressure. I would think it’s negative. I thought it would be a plugged tank vent so I pulled the trunk mats out and I don’t see a vent tube anywhere. RealOEM shows tanks with and without vents for this car. If there is no vent then wouldn’t the cap need to be vented? Here are some pics

side question, how do I find the month of manufacture? It’s not on any tags that I can find.

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4CF2DB71-23A8-4F72-B9B4-C221F75F7242.jpeg


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edit: I cleaned the cap and this was hidden by dirt. Looks like it’s an attachment point for a lanyard.
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Edit#2: while cleaning further the “attachment point” came out. Is this a vented cap and someone put that cotter pin in it for some unknown reason, then grime built up and created a seal around it?
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Conclusion: taped a hose to the cap and blew through it, sure enough it’s vented. Must have been plugged (inexplicably) by the pin. Another one for the records. Thanks for watching!

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americium said:
I thought I fixed it with aforementioned items but yesterday I took my wife out for a spin and it was cutting out again. (Wife won’t get in it again until I certify it’s fixed).
Click to expand...

For the sake of efficiency, we agreed combine a mechanical test drive with a planned Trader Joe's errand. The Webers were newly rebuilt and tuned well. I had just finished making some simple change (possibly the fuel filter) but I had kinked the fuel hose to the front carburetor inadvertently. The car took us to the grocery store parking lot dutifully, sipping on the supply of fuel in the front bowls. However, on the return trip the engine became fuel starved the same way you describe, as three cylinders had begun breathing air with no gasoline in it. Husband, wife, E9, and five different styles of cheese crept off the main road and into a sleeping office complex parking lot using the starter alone for forward motion.

I said something very reassuring. Just take my word for it; I have a soothing demeanor in the face of difficulty, especially when I am the likely culprit. My wife was unreassured. After checking inside the air cleaner I found and straightened the kink, obscured as it was by some coolant hose. Before closing everything up I started the engine just to be certain. The front carburetor belched a vertical fireball which is still spoken of to this day in the otherwise serene moments. Anyway, that it meant the fuel was back or the fact that everything felt pretty fine and peppy all the rest of the way home somehow wasn't the memorable part to both of us.

I intend to use this as an example of why converting to fuel injection is a good use of household funds.
 
HB Chris said:
If cap says ohne luftung it is not vented.
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Well that’s interesting. It does say that, which means without ventilation (thanks to translate). Then I’m back to how is this tank supposed to be vented? And why does the cap that’s says that have a hole that flows air?
I drove around for an hour and it was mostly ok. It idles better but did have a very brief loss of power but it didn’t repeat.
 
That hole was drilled in a non vented cap when the prior owner couldn't find a vented cap. Be careful that it doesn't slosh fuel out of the hole with a full tank, accelerating, or going up hill.
 
Blinkling said:
For the sake of efficiency, we agreed combine a mechanical test drive with a planned Trader Joe's errand. The Webers were newly rebuilt and tuned well. I had just finished making some simple change (possibly the fuel filter) but I had kinked the fuel hose to the front carburetor inadvertently. The car took us to the grocery store parking lot dutifully, sipping on the supply of fuel in the front bowls. However, on the return trip the engine became fuel starved the same way you describe, as three cylinders had begun breathing air with no gasoline in it. Husband, wife, E9, and five different styles of cheese crept off the main road and into a sleeping office complex parking lot using the starter alone for forward motion.

I said something very reassuring. Just take my word for it; I have a soothing demeanor in the face of difficulty, especially when I am the likely culprit. My wife was unreassured. After checking inside the air cleaner I found and straightened the kink, obscured as it was by some coolant hose. Before closing everything up I started the engine just to be certain. The front carburetor belched a vertical fireball which is still spoken of to this day in the otherwise serene moments. Anyway, that it meant the fuel was back or the fact that everything felt pretty fine and peppy all the rest of the way home somehow wasn't the memorable part to both of us.

I intend to use this as an example of why converting to fuel injection is a good use of household funds.
Click to expand...

That’s turning lemons into lemonade. I might need to follow your lead on that.
 
W&N only sells one type of cap for this car, except it can be lockable or not. It looks like the ohne luftung variety.

and it says it’s for all E3
 
Dick Steinkamp said:
That hole was drilled in a non vented cap when the prior owner couldn't find a vented cap. Be careful that it doesn't slosh fuel out of the hole with a full tank, accelerating, or going up hill.
Click to expand...

maybe they drilled the hole and put the cotter pin in to reduce fuel escaping. Then as it got dirty it sealed up and caused the issue I was having
 
Hmm, my 72 E3 has a vent in the neck of the tank with that fragile blue plastic hose. I am wrong to think this is the vent and I actually have a vented cap too? I learn something new each day.
 
bavbob said:
Hmm, my 72 E3 has a vent in the neck of the tank with that fragile blue plastic hose. I am wrong to think this is the vent and I actually have a vented cap too? I learn something new each day.
Click to expand...
When the vents were introduced the cap became ohne luftung, without venting.
 
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