Stalling while driving

[goldie]

Hello,

My '71 Bavaria is stalling out while driving. What will happen is that the car will quit accelerating despite the fact that I'm giving it more gas. It's not at all gradual -- the car lurches and bucks. Then it will stall out, although the electricity will stay on. Sometimes it starts back up right away, sometimes I have to wait a few minutes.

There's something about the way the car gets hung up that *feels* like an electrical problem. In my experience something like a bad coil or voltage regulator causes such unpredictable behavior. However, swapping in a new coil did not resolve the problem and the alternator is an internally regulated unit (installed 5/14). For laughs I swapped in a spare fuel pump I carry in my trunk, but the problem persists.

The issue may be temperature related since it seems as though the problem occurs when the engine is warm.

Any ideas? All of my connections in the engine compartment appear tight.

Many thanks,

daniel

 

[JimV]

Daniel,

I would suggest that the first thing to check is your points. Check their condition, set the dwell (35 - 41 degrees) if you have that capability or use a feeler gauge - .014 to .016. Condensors are cheap, so I'd say replace it. Same with the distributor cap.

Good Luck,

Jim

 

[goldie]

I should have mentioned that I replaced the points 11 years ago with a Crane XR700 electronic ignition.

Cap is about a year old, rotor is new. The external resistor has been there since before I owned the car, and, come to think of it, I don't think there's ever been a condenser on there.

daniel

 

[jmackro]

The issue may be temperature related since it seems as though the problem occurs when the engine is warm.

Vapor lock. I assume your Bavaria is carburated. Do you have thick, phenolic heat isolators between the manifold and carbs? Might there be vapor lock in the fuel line between the tank and fuel pump?

Do the symptoms persist in the morning/evening when temperatures are cooler?

I don't think there's ever been a condenser on there.

No, there wouldn't be if you have a Crane XR700 electronic ignition.

 

[goldie]

The car has dual Weber 32/36 DGEVs and the isolators are present.

Vapor locking is a possibility, but consider:

- It happened once at night (approx. 70 degrees F); and,

- One time today when it happened I sprayed starter fluid into the carbs. The engine did not spring to life for even an instant.

Many thanks,

daniel

 

[Stevehose]

ignition switch failing?

 

[bavbob]

FWIW: I had an 82 320i that did this exact thing. It turned out to be a crack in the copper wire within the distributor. I would have never know, some old time BMW technician mentioned it. The crack is too small to see, happened when the car was warm. I still vote ignition switch first.

 

[goldie]

Believe it or not, I replaced the ignition switch within the past year! I do recall having to whip out my soldering gun and to make a slight modification to the wiring, so perhaps my handiwork isn't all it's cracked up to be.

I'd prefer vapor lock.

daniel

 

[amg5872]

I had a very similar problem last year. Although I had loud backfiring, which I don't think you mentioned. For what it's worth, mine turned out to be an issue with the points. Good luck.

 

[bavbob]

Guys read above/below. Coil swapped, electronic ignition installed.

 

[goldie]

Today the ambient temperature plunged 20 degrees and it was raining. After a long, long drive, the Bavaria ran flawlessly. Unless there's something I've overlooked, it must have been a simple case of vapor locking between Wednesday and Sunday.

Many thanks,

daniel

 

[Sven]

Have you checked the wire from the coil to the distributor? I had one with a badly corroded connection once. It was not easily visible until you pulled the rubber boot back. It could explain the sudden drop out.

 

[73tiiguy]

Goldie, a previous bav I had displayed a similar running problem. The motor would quit at random times. I thought it was fuel related, but it turned out to be some failed wiring up by the drivers side head lamp. Follow the wires from the coil into the loom which traverses the headlamp/radiator bulk head. I found my fault where the loom makes a turn at the headlight area.