Engine cutting out

[JacD]

I have a 1966 minor fitted with a 1275 Marina engine, HS4 carb, a water heated inlet from a Mini and a lager bore exhaust system. It also has a 23d Accuspark electronic distributor and sports coil (both new in sept 16) and it has been running on this system for the last 10 years.

The car keeps dying on me as if it has run out of fuel but if I turn the ignition of and back on again the engine fires up strait away. I can go for another 15 odd miles and it will do it again. I have taken the top of the float bowl off when the engine died last time and it was full of fuel. This leads me to think it is an electrical problem ?

Earth leads, solenoid connections, all electrical that I can think of cleaned.

I have had the car for 30 years and do approx 10,000 miles per year.

[SteveClem]

Drill a hole in the filler cap?

[RobThomas]

Fuel pump points?

[oliver90owner]

When you turn the ignition switch back on, does the fuel pump tick more than usual (at a normal enine stop and restart). That may help you diagnose the fault.

It may be a partial vacuum being built up in the tank or it could be some thing restricting he fuel pickup in the tank. Checking the pump delivery rate would be good, as it may only just be pumping sufficiently most o the time.

Any particular time the fault occurs? High speed, heavy pulling, driving sedately, idling along?

What do you call ‘straight away’? Instantly, or within a few seconds of turning on the ignition?

If electical, it icould be a loose joint, which disconnects due to vibration and then reconnects when the vibration stops. Unlikely much else as failing coils (or electronics) usually fail completely or need to cool before struggling on.

[JacD]

Tends to cut out when I am doing about 50mph not necessarily under heavy acceleration and so far never when I am doing short trips. Engine cuts out, foot on clutch ignition off, ignition back on after a few secs clutch out and away we go again. If I do nothing and don't put foot on clutch the engine will sometimes fire up again
Did not notice the pump ticking when it happened today! looked at pump at weekend and points look ok not pitted or burnt.

[myoldjalopy]

You say it "keeps dying on me as if it has run out of fuel". Do you mean it splutters and staggers on for a bit before stopping, or does it just suddenly stop dead without warning?

[JacD]

Stops dead without warning no splutter or misfire and ignition light does not come on. pump filter clean.

[simmitc]

If the ignition light does not come on when the engine stops then that suggests that there's no power, and that would certainly cause the engine to stop dead. Check all wires and connections, including on the back of the ignition switch. Is the switch OK? Do other elctrical items such as indicators and wipers continue to work immediately after the engine stops?

[JacD]

have replaced ignition switch as that was original and very sloppy. All other electrical items work. wipers kept going when it was raining as well as indicators lights, radio etc Going to replace coil next!!!

[oliver90owner]

Send the old one to me, please. Pretty sure I could use it!

Has it only done this since changing the ignition switch?

The ignition light will/should only come on if the engine comes to rest - when the dynamo stops turning. If it is not coming on when the engine has stopped turning, definitely send me your old coil!

Seems like a poor connection somewhere, probably in or around your new switch.

[1000179]

I had a vey similar sounding problem with our traveller which was the coil.. helped by a faulty electronic ignition.

[myoldjalopy]

This really is a bit puzzling........in all probability we haven’t got all the necessary facts available.
As has been pointed out, if the engine cuts out and then stops turning (when you depress the clutch) so that the dynamo stops generating, then the ignition light should come on. But you say it doesn’t, which would suggest a fault either in the switch itself, its internal wiring, incorrect/poor connections at the switch, or a fault in the wiring between the battery and the switch. If this is all correct, I would not suspect the coil, as this is ‘downstream’ from the ignition switch - which is Oliver 90's point. Therefore my first question would be the same as Oliver 90 – did the problem arise before or after fitting the new switch?
On the other hand, if the ignition light goes out when the engine stops, I wouldn’t expect the wipers or indicators to work either, unless things are wired incorrectly, or the ignition light bulb is blown or poorly conected . Does the ignition light come on normally when you turn on the ignition from first getting into the car?

[JacD]

Fitted new switch after problem started as i thought this might be the culprit. Ignition light comes on and then goes out when engine starts. As I said before when engine cuts out ignition light does not come on and all electrical devices work. Could there be a problem with the wiring between the switch and solenoid? how do I check?

[simmitc]

The solenoid is only effective in starting the engine - it switches the high current required by the starter motor, but is irrelevant for normal running. If the problem occurs frequently and you are happy to fiddle under bonnet, then:
a) Remove the white wire from the coil (leave the white/black wire in place to connect to the point).
b) When ready to start, run a wire direct from the non-earthed battery terminal to the coil where you removed the white wire
c) Start the engine and drive normally
d) When you need to switch off the engine, remove the wire from the battery and the coil

NB whilst this will completely bypass the wiring and the ignition switch, you will not be able to switch off the engine without opening the bonnet. A refinement would be to run the wire into the cabin with a toggle switch that you could use to control the circuit. Do not leave the wire connected without the engine running as it will flatten the battery and possibly burn out the coil. Take appropriate precautions to ensure that the wire is secure and insulated, and cannot short out anywhere.

This test will prove whether the issue is switch/harness related - if you have not problems then then that's where the issue lies, if you still have problems then it could be other ignition components; bit it will not explain why the ignition light is behaving incorrectly.

[myoldjalopy]

Good thinking! That test will, indeed, rule in or out any wiring issues 'upstream' of the coil. Just to clarify further, the white wire to be removed should be from the SW connection on the coil (assuming the coil is wired up correctly in the first place). Of course, the coil connections may be marked -ive and +ive, rather than SW and CB, in which case it will be the -ive connection, if your car is positive earth (and vice-versa if it is negative earth). I only mention this because some cars (like mine!) have had their wiring meddled with at some point in the past and the colours don't always match the coding.
As a precaution, I would make sure the battery connections and earthing point are scrupulously clean and secure before commencing this test. The car may need to be run like this for a number of journeys to reach a conclusion - if the problem is intermittent - but if there are no problems then you can focus on the wiring/connections/switch from the coil back to the battery.

[Chipper]

Also check the engine-to-body earth strap - a cause of many a breakdown in cars, if it's loose or badly frayed!

[JacD]

Started again ! systematically went through all electrical connections including the engine to body earth strap (not done before) and the car seems to be running fine time will tell as have only done about 80 miles but not missed a beat yet. So many thanks to all who replied to my post.

[myoldjalopy]

Sounds promising but, as you say, time will tell. Fingers crossed then that it was a dodgy (loose or corroded) electrical connection somewhere that you have rectified. Not uncommon on an old car...........

[oliver90owner]

D**n, I could have done with another spare coil!