Type 3 Won't Idle :*(

[nickdabs]

Hi,

I have a twin carb auto 69 fastback. Recently it stopped idling, it drives but the moment you take your foot off the accelerator it just dies.

The previous owner told me that someone had fitted an electric fuel pump to the car and I should consider changing that, so I did. it now has a new mechanical fuel pump. After fitting that the problem went a way for a while giving the car enough time to pass its MOT.

Now the problem has reappeared with avengeance and the car is basically undriveable. I tried running the car directly off a petrol to ensure that a blockage from the tank to the carbs is not the root cause to no avail.

Any thoughts please?

Cheers,
Nick.

[miketyp3]

Hi Nick,
Firstly, if the car drives but stalls on tick over then it can't be a problem the fuel pump. It has to deliver much more fuel when the car is under load so the effect would be totally opposite.
It sounds to me as if it might be either, a blockage in the air correction jet(carb), a vacumn leak in the induction circuit (the rubber hoses on the ends of the big balance pipe are the prime suspects) or a sticky distributor.

A quick check you can do on the distributor is to suck the end of vacumn pipe that feeds of the LH carb.
With the distributor cap off it should respond to the vacumn and then spring back. If it moves but then sticks then it more than likely just needs a bit of freeing off.

Don't forget to check that everything on the ignition (points gap, timing, leads, condensor and plugs) are as they should be.

Mike.

[nickdabs]

Hi Mike,

Thanks for your suggestions. I agree the fuel pump is a side issue and the fact that this issue came, went and reappeared when the pump was changed is probably a coincidence.

I will try the things you suggest.

Cheers,
Nick.

[Editor]

Have the carbs got their power supply to the electromagnetic idle cut-off jets? The black wires go from ignition coil + to the auto chokes and to the barrel-shaped devices on the sides.

They do 'just what they say on the tin' and would certainly cause this problem. Maybe a connection has fallen off. Sometimes just one carb connection is enough to stop it idling properly.

Occasionally, the ICO jet coils can fail. Test with ignition on, and remove connector then touch it on the contact - should hear and feel a click from the device.