Engine suddenly quits, then starts up and runs well again.

[rbtrader]

My E9 has been running great! I have a Weber carb and a Pertronix ignition, and everything seems crimp to have been dialed in well.
Yesterday I was driving along and the engine started to “drag” a little, and then suddenly die. I pulled over to the side of the road, and turned the key and it started and ran great again. About 10-20 miles later, the same scenario. I was trying to get somewhere so I persisted, and had it fail every 10-20 miles, but then start right up and run great.
I am not a great technician, but I have heard that fuel lines can delaminate and crimp on the inside cutting off the fuel supply. Then they open up again when the car shuts off.
Could this be happening to my car, or should I look in a different direction?
Any suggestions are welcome!
Rich

 

[sfdon]

Take your gas cap off...

 

[aearch]

what about fuel vent return

 

[Honolulu]

What sfdon is saying, is that the tank has to be vented so that fuel drawn by the fuel pump, is replaced by air entering the tank. If not replaced, the fuel pump can't pull much vacuum, and the car starves for fuel.

I've experienced this on my 2002 when I 'cleaned up' the engine compartment and removed the charcoal canister from under the battery, and the hose connection to it. The car stalled on the next uphill. Fortunately I remembered the possibility and restored venting to the tank. This all happened when I was young and dumb. It seems like only yesterday...

Look at the fuel cap, it may say "ohne luftung" which basically means "without venting". Those with such caps must ensure the tank is vented by another means. If you still have the charcoal canister, tank venting can be accomplished through the hose connecting to the fuel filler neck (as long as the charcoal canister isn't plugged). I think there is also a vented cap which will not have "ohne luftung" on it. Others may chime in to clarify which versions use either cap.

 

[HB Chris]

How old is the coil and does it have a ballast resistor?

 

[rbtrader]

Thanks for the great suggestions! The vacuum sounds exactly what is happening. I will check for that issue. My coil is an almost brand new Flamethower, and I will also look into the ballast resistor.

Rich

 

[sfdon]

Make sure your key is not sloppy.

 

[rbtrader]

Thanks for all the input, all good ideas that I will monitor. To start with a potentially easy fix, I pulled up the trunk floor boards and checked the fuel filter. It was totally full of black particles!
I bought another fuel filter at the NAPA store, and installed it. I have driven the car for about 20 miles and it continues to run well and the filter is still clear. I am not sure if I got a bad tank of gas or my gas tank is beginning to deteriorate. Needless to say, I have an extra fuel filter in the trunk and I will continue to check it.
The help provided by this site is much appreciated!

 

[Stevehose]

Remove the tank sender unit and have a look inside with a flashlight. Might need to renew it with por-15 system to remove the scale etc.

 

[Honolulu]

Well, you can continue to use filters to strain out cr*p in the tank, or inspect the tank by removing the gage assembly. It just so happens I have a salvaged tank that was cleaned and coated with POR-15, inside and out. Give a shout if you're interested.

 

[adawil2002]

Had that exact scenario when I ran a Pertronix. Remove the Pertronix unit and either return to points and condenser or buy a 123 distributor. What is happening is the Pertronix is overheating and cutting out. The longer you run the car the shorter the interval between times the engine will die.