Car will start and occasionally drive a few miles, then splutters and stops!

[DavidAH]

1966 two door saloon with a 1098cc engine and standard carb.

When this first happened I removed the fuel hose from the carburettor and turned the ignition on….there was no clicking sound from the pump and no fuel came out of the hose.
When I tapped the fuel pump it started clicking and pumped fuel out of the hose.
Thankfully this got me home and I ordered and fitted a brand new SU pump AUA66.
Next time I went out in the car it spluttered after a mile or so then stopped running again. I thought it could be fuel vapourising, as the original fuel hose ran across the top of the hot exhaust manifold, so I fitted a longer hose and re-routed it around the side, avoiding the manifold.
Ignition seems fine and car starts first time, but it won’t run for anything more than about five minutes, suggesting it’s running on the fuel initially pumped into the carb, then stopping.
I have a locking petrol cap fitted. I tried starting and running the car without the cap fitted, but it was no better.

I cleaned the fuel pump points with a bit of card then removed the fuel hose from the carburettor and turned ignition on….again there was no clicking sound from the new pump and no fuel came out of the hose.
When I tapped the fuel pump it started clicking and pumped fuel out of the hose.
It did this several times and I had to tap it before it would produce a steady stream of fuel.
It seems like a dodgy new fuel pump, but wondered if anyone else had any ideas?

[svenedin]

First clean the pump points again.

I’d suggest checking the electrical connections to the pump as a bad connection might respond to your thump! There should be 2x earth connections, 1 on the side and another on one of the pump securing bolts. Both are required. Then a live connection on the cap. Check the connectors are bright, clean and tight. It would also be useful to test the resistance of the Earth connections between pump earth and the battery Earth terminal. 12 volt stuff will not tolerate dirty connections.

You may have a lot of crud in your fuel tank which the new pump happily sucked in. Remove and clean the filter in the fuel pump. IF there is a lot of debris consider draining the fuel tank (drain plug underneath).

Finally, you might have a needle valve that is sticking in the float chamber. Remove float lid (have a new gasket to hand), clean float chamber then remove the pin that holds the float and remove the needle valve. Clean out with carb cleaner or petrol and blow through with air. Check the float is correctly adjusted so that the correct level of fuel in float chamber is maintained

If it is a faulty pump consider getting the electronic version (positive and negative earth versions not interchangeable). This has no points and is better suited to infrequently used cars. The fuel pump points are to some extent self-cleaning but this relies on regular use. Alternatively you can buy a kit to convert a points pump to electronic

My guess is a bad electrical connection

Stephen

[DavidAH]

Thanks for the advice Stephen…..will give those suggestions a try

[svenedin]

You're welcome David. Please let us know how you get on.

Stephen

[Nickol]

After its winter hibernation, I went for a short drive and got the same symptoms which is new to me as since the 10 years I have had the car, this has never happened before. Engine cuts out, wait a few minutes and it starts again , then stops and repeat the whole procedure.
The fuel pump has always been a bit suspect so I thought this would be a good time to replace it. Decided for the top of the range modern SU which is not available in Germany and thanks to Brexit takes at least 10 days to arrive from UK instead of the previous 3 or 4 days. I even had to collect it from DHL in order to pay the customs, but that is by the way.
Fitted it, went for a test run and the same symptoms prevail - motor stops- wait a few minutes, it starts again.

Now what did occur to me is that the engine always has stopped going uphill. Could this be a clue? Anyway I will have a look at the float chamber now to check it for cleanliness etc.

[mowogg]

Do you have a spare coil you can swap over too -they can fail in funny ways.

[ManyMinors]

Easy to check the pump. When the car stops, just check to see if it is pumping fuel from the outlet pipe.....
The symptoms you have are more likely the coil - as mentioned already - or the condenser.
Another possibility especially as you mention going uphill (when you're using more fuel) is perhaps the car is fitted with an extra fuel filter? If so, could that be partially blocked??
Also, you do have the correct fuel cap fitted? with a vent??

[oliver90owner]

If you have to wait a few minutes before it will restart, you have plenty of time to check whetheror not the ignition system is at fault. That would be my first simple check, immediately after it stops.

[les]

I would suspect it’s on the fuel side, with ignition, personally can’t see how it would just stop functioning if it initially started and run.
Having said that, I did once have a dodgy rotor arm that run briefly then stopped. Interesting to know what you find.

[Nickol]

It is always nice to have feedback from problems when they are solved.

I Removed the cover of the float chamber which in itself made for a new problem in that one of the cover bolts was a bit stiff and sheared off. For the moment I have drilled and tapped into the embedded bolt M3 and secured it back that way. There was a bit of dirt in the chamber but not excessively so and the float valve seemed free enough.
Then on replacing the fuel line to the carb I noticed the hose clip was slipping so I replaced it with a new one and was able to tighten this up probably better than before.

Then the test run. Drove uphill for 2km and stopped at the T junction - motor cut out and even after the normal wait, did not want to start. Opened the bonnet to have a look.

It is never the coil but..........one of the low tension wires had come off! I slipped it back on noticing how loose a fit it was . Engine started no problem. Back home I was able to press the spade connector so it was a tighter fit. Then a new test run just now in the sunshine - all ok! Perhaps the clue of uphill was relevant in that gravity had pulled the wire off? It was indeed a very loose slide fit.

A success methinks.

Also noticed a water leak at the heater control valve coming from the hose. Cut the end off and refixed it . Seems ok as well.

You get good days sometimes. To quote Henning Wehn " In Germany we do not swear at all - the reason being, things work".
No swearing today anyway.

[mowogg]

It's really good to hear your have made progress.

I remember my sister had a mini many years ago. I got home to be told it was broken down. There was lots of people looking at it when I arrived but I found thr low tension lead to thr coil had broken off. Thr aa recovery man had missed it too.



I

[oliver90owner]

It is never the coil but..........one of the low tension wires had come off! I slipped it back on noticing how loose a fit it was . Engine started no problem. Back home I was able to press the spade connector so it was a tighter fit. Then a new test run just now in the sunshine - all ok! Perhaps the clue of uphill was relevant in that gravity had pulled the wire off? It was indeed a very loose slide fit.


There you go! A simple check when it showed the fault (by checking for a spark at the plug(s)) would have immediately shown it to be an ignition fault. Would have saved aggravation with parts which were, to all intents and purposes, operating correctly.

Simple steps in diagnosis virtually always pays off, before taking things apart.

[myoldjalopy]

So really - its never the coil, but it may be one of the connections to the coil!

[geoberni]

Generally speaking, if the description of 'Splutters and Stops' is correct, I would be looking at a fuel related matter.
Ignition faults don't splutter.
They can run rough, i.e. if a plug/lead related problem, so perhaps not sparking correctly or just stop stone cold dead if coil related.

[DavidAH]

Following advice, I rechecked and cleaned the pump points.
I also cleaned up one of the mounting point holes to ensure there was a good earth.
Checked pump power supply ….no problem.
Checked earth resistance….no problem.
Then checked the carburettor float bowl….empty!
Blew through the delivery hose to carb…no blockage (new hose).
Blew through the float bowl …..no blockage and float working correctly.
Replaced condenser, rotor arm, distributor cap and the coil (as the clamp had been over tightened and had crushed the original coil)…no change.
Decided that it must be the replacement pump, so contacted ESM who sent me another and I returned this one. I asked them to send an electronic one rather than one with points.
Pump fitted, car starts and continues to run! Took it for a couple of test drives and all seems well.
Happy days!
Thanks very much everyone for your help and advice

[Nickol]

It is never the coil but..........one of the low tension wires had come off! I slipped it back on noticing how loose a fit it was . Engine started no problem. Back home I was able to press the spade connector so it was a tighter fit. Then a new test run just now in the sunshine - all ok! Perhaps the clue of uphill was relevant in that gravity had pulled the wire off? It was indeed a very loose slide fit.


There you go! A simple check when it showed the fault (by checking for a spark at the plug(s)) would have immediately shown it to be an ignition fault. Would have saved aggravation with parts which were, to all intents and purposes, operating correctly.

Simple steps in diagnosis virtually always pays off, before taking things apart.

Very true - I am a bit intrigued though as to why the car did restart before- I can only suppose that the LT wire was loose and had a wobbly contact which temporarily gave a good connection allowing me to do the few km to get home. Whatever - all well now.