1956 P4 Stalls At Speed


New Member
I'm wondering if I can get a little technical help?
My P4 has taken to stalling while at speed. Usually at higher revs and on an incline.
Does anyone have any ideas as to where I should be looking to fix this?

I cleaned out the fuel tank about 6 months ago which made a great difference but I'm wondering if the inside of the tank is rusting again.

Many thanks!
Have you checked your induction system for blockages? I don't know the 6 cylinder units very well, but stalling at speed under load can just be down to a dirty air filter. Other easy checks to start with would be distributor (Shaft loose, weights seized, vacuum not working), blocked breather pipes.
Does the engine recover if you ease up on the throttle? You're on the right lines with dirt in the tank restricting flow, so the next thing is a partially blocked or weak fuel pump. You could also try a sedimenter bowl between the tank and the pump to see if there's any dirt coming from the tank.

Sedimenter bowl..jpg

There are also left to right ones to aid mounting, they also separate water as well if any.

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Thanks so much!
I've checked the air filter, distributer, fuel tank intake and they all look good.
Yes the engine sometimes recovers if I ease up on the throttle especially now I have a new battery.
I've emptied/cleaned the sediment bowl before the carburetor and I'm seriously considering installing some kind of filter between the fuel tank and the fuel pump.
I'll be able to take it out for a test run in the next few days and I will report back.
Does the car have an electric or mechanical petrol pump? The diaphragms in mechanical pumps often have problems with modern petrol and then the flow rate is no longer sufficient at higher engine speeds.
Greetings Bernd
The 90s have an electric pump in the corner of the boot. Ideally the sedimenter should be between the tank and the pump to take out the larger crud and water, a filter goes between the pump and the carb to take out the fines. As the engine recovers it means it is getting insufficient flow, so as said blocked or weak pump.