Hey I'm really trying to learn mechanics and older cars like my polo, my polo was my first project car as well as the same car I learned to drive in. My polo now has an intermittent start and has recently had a new distributor cap + rotor arm, unless this has some relation to the distributor but I believe it was just a coincidence, I drive it and would fail to start after half a day and after a few days it starts fine and repeat. I'm not sure if my polo has an electric choke and if it could even be because of that? It all seems odd and doesnt directly link to one thing with my limited knowledge and experience.

To simplify & expect my issue:

• Intermittent start (works fine once, then wont work after half a day or so of rest and will work after a few days)

• Does my polo mk2f 1991 - 1L with carb likely have an electric choke and if so where would it be?

• Rarely it will start fine but dies after few mins of idle (3-5 mins) and wont turn back on again and repeats like previously

• Not 100% but distributor seems fine after replacement parts and I've also tested a spark from HT lead

• I can hear the fuel pump whirl when turned to ignition

• I only suspect something with the carb as I have not touched it and have yet to service it/take it apart

Any help and advance would be greatly appreciated and I wish you well on your own polo journeys. 👍

Edited Wednesday at 18:332 days by Alvin.32
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Do you mean it can manage a cold start, but not a warm engine start?

It has an autochoke if you don't need to pull a lever on the dashboard towards you, then gradually push it in as the engine warms.

Autochokes on the Weber TLA and the Pierburg 1b3 carbs used on 1l are a combination of electric bimetallic strip and coolant expansion.

If the flap is angled not fully opened it could be too rich at warm start. Fuel consumption would be bad too. Spark plug tips would be coked.

When cold the flap should be closed, then when engine fires vacuum from the descending pistons acts on the pulldown unit to crack the flap open a fraction to let air in. The gap needs to be just right.

As engine warms choke flap should move to fully vertical.

Might just need lubrication.

As engine cools the flap will close again, over several hours... typically over night.

Thanks for the response, and no it is intermittent in all sorts of conditions so I believe it isn't due to engine temp as far as I'm aware, usually works until after 8hr work shift.

Usually after a drive or two it might manage but afterwards it wont work when I come to try again after a few days. I've had the garage take a look and helped me assumably fully disconnect the rest of the immobilizer as it was faulty in the past anyways, assuming that has now been fully removed from the equation it is just air or fuel starvation.

In this case I do have an electric choke I was also curious how it might mix in with this problem.

As I already said, it wont start even after days but randomly it will and it seems fine when it gets going, usually drives somewhat well besides idling too long and sometimes when setting off depending on how long I let it warm up, I tend to give it between 2-4 mins. Most recently it started and died after idling for a few mins and hasn't started for two days, I've tried both pumping gas pedal and pull pedal down tricks and doesn't seem to work, my next try would be to check if it smells of fuel or not in carb and check flap.

I appreciate the help.

I wonder if the base mount of the carb has developed a fine vacuum leak.

It should be firm against the rubber, but insulated against vibrations. The rubber hardens over time. Can you wobble the carb left right or back and forth?

Will the engine fire with some Easy Start spray

(diethyl ether) or a small amount of fuel dribbled down the carb throat?