Engine cuts out

[Neilo]

Hello all. I have a standard 1.6 pinto and after a couple of miles it coughs and splutters back fires a couple of times and stops. Leave it til the next day and it starts first time but when driven it’s stops again.  The car only passed IVA last October so I haven’t been far at all. Since this started I have: Changed the manual fuel pump for another. Filled the tank with new petrol (super) and put in an additive. Removed the old distributor and replaced with Bestek ignition system. Set the timing to 10 degrees as per Bestek instructions. New NGK spark plugs. New HT leads. Re Plumbed the fuel lines and taken out any sharp bends. Checked the diaphragm in the carb to see if it had a hole and was pulling air in. All to no avail! Next step is to swap the carb and after that I’m stumped. Has anyone had the same problem and or any clue what it is I can do to put this right? Many Thanks
 

[Darren Knowles]

Try ignition coil may be failing when hot ? 
 

[Neilo]

It’s brand new from Bestek and the same was happening with the old coil but thanks for the reply. 

[IanS]

Auto choke stuck on??

[Neilo]

Ian. It has a manual choke which is fully working. Thanks for your input though.

[alantoon]

is your carb a weber 32/36 if so it has a small gauze filter where the fuel binlet joins the carb-unbolt the pipeand the filter is pushed into the carb body, wash it out and rebuild.

another thing you didn't use silicon whehn you fitted the sender unit in the tank as that could be blocking the pick up in the tank.

Edited June 5, 2023 by alantoon

[nelmo]

Obviously not electrical as it starts and runs for a while. Almost sounds like it's filling the carbs with petrol on startup but no more, so the engine runs on the fuel in the carb and then runs out?

What's a manual fuel pump? You don't actually have to manually pump it as you're driving along? 

[IanS]

Are the valve clearances correct?

As valves heat up the get longer and if clearance is tight they do not close fully. All sort of strange things occour.

[Sparepart]

The pickup pipe in the tank has filter on the end. Could be a layer of crap in the bottom of the tank made up of reatively heavy bits, when the pump sucks the petrol up the bits are gradually picked up on the outside of the filter mesh until no more petrol flows. Then, left idle, the bits drop off under their own weight. You could run the engine until it stops and then as quick as you can pull out the gauge/pickup pipe to examine the filter.

[Neilo]

On 6/5/2023 at 8:10 PM, nelmo said:

Obviously not electrical as it starts and runs for a while. Almost sounds like it's filling the carbs with petrol on startup but no more, so the engine runs on the fuel in the carb and then runs out?

What's a manual fuel pump? You don't actually have to manually pump it as you're driving along? 

I meant Mechanical pump as in not electrical 

[Neilo]

23 hours ago, Sparepart said:

The pickup pipe in the tank has filter on the end. Could be a layer of crap in the bottom of the tank made up of reatively heavy bits, when the pump sucks the petrol up the bits are gradually picked up on the outside of the filter mesh until no more petrol flows. Then, left idle, the bits drop off under their own weight. You could run the engine until it stops and then as quick as you can pull out the gauge/pickup pipe to examine the filter.

There isn’t a filter on the pick up pipe but I dio have an inline filter which I have changed 

[Neilo]

On 6/5/2023 at 8:09 PM, alantoon said:

is your carb a weber 32/36 if so it has a small gauze filter where the fuel binlet joins the carb-unbolt the pipeand the filter is pushed into the carb body, wash it out and rebuild.

another thing you didn't use silicon whehn you fitted the sender unit in the tank as that could be blocking the pick up in the tank.

I’ll give it a go thanks. No silicone was used but there was some dirt in the old filter when I removed it. 

Edited June 10, 2023 by Neilo

[Sparepart]

Possibly a frivolous comment, but perhaps there is no air getting into the petrol tank, so after a while the pump is not able to extract any liquid petrol. I would have thought that if the tank is sealed, at some point the partial pressure would mean that when the pump sucks, the petrol starts to vapourise and either the pump pumps vapour or the petrol just moves back and fore in the pipe. I suppose you would hear a hiss when taking the filler cap off, if this were the case.

[Neilo]

On 6/10/2023 at 6:28 PM, Sparepart said:

Possibly a frivolous comment, but perhaps there is no air getting into the petrol tank, so after a while the pump is not able to extract any liquid petrol. I would have thought that if the tank is sealed, at some point the partial pressure would mean that when the pump sucks, the petrol starts to vapourise and either the pump pumps vapour or the petrol just moves back and fore in the pipe. I suppose you would hear a hiss when taking the filler cap off, if this were the case.

Thanks for your advise. There is a vent on the fuel filler so wouldn't cause the vacuum in the tank. 

[Longboarder]

And the vent is working for sure.? Try a drive with the filler cap off. If it still happens then you need to confirm your pump is still working when the car comes to a stop. Still with the fuel cap off, whip the fuel line off the carb (not anywhere else) and lead it to a bottle/jar. Turn over the engine on the starter. You should have good spurts of fuel. (This tests the whole fuel supply line from tank pickup to carb including each component along the way)