Engine cutting out while driving

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martyn yates
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Engine cutting out while driving

Post by martyn yates »

Has any one any ideas as to what may be causing my 1957 948 moggie to cut out. While driving the engine will just cut out, if I switch off the ignition and turn it back on all is well again. Some days it wil happen and other times it will be ok. Any suggestions?
oliver90owner
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Re: Engine cutting out while driving

Post by oliver90owner »

First of all, determine whether it is ignition or fuel related (like check for sparks at the plugs in the exact condition of it cutting out. Does the fuel pump click multiple times on resetting the ignition keynto the run position?

Likely an electrical connection in the ignition system or pump circuit, but need at least some diagnostic input from you to offer realistic guesses or pointers for further diagnosis. Things like do the lights still work properly might be an important piece of info!.
martyn yates
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Re: Engine cutting out while driving

Post by martyn yates »

I have been wanting to pull over at the time when it happens to check the fuel pump, but you might know it's never in a quiet safe spot. All the electrics and lights are working when the engine cuts out.
simmitc
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Re: Engine cutting out while driving

Post by simmitc »

Is the cutting out related to a particular speed or load?

Some possible causes:
  • Loose connection in ignition system
  • Faulty ignition component *
  • Thin LT wire inside dizzy shorting out as vacuum advance operates
  • Blocked air vent in fuel cap
  • Fuel pump
  • Dirt in carb - sucked to block jet, engine stops, vacuum goes, debris falls away, fuel flows again

* Typically condenser or rotor arm, but it doesn't sound quite right for this. Change only one component at a time until problem solved so that you know which was the faulty item.
James k
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Re: Engine cutting out while driving

Post by James k »

It would also be useful to know if it cuts out instantly or sputters first. Also, are there any erratic noises from the fuel pump before it cuts out or, as Oliver asked, when you switch it back on?
martyn yates
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Re: Engine cutting out while driving

Post by martyn yates »

First symptom is it just misses then cuts out, it can be at any time on the level coming a hill, on the motorway or just pottering about. I have fitted a refurbished carb, and manifold as mine had a hole and was blowing, I was hoping that was the issue but no. It has a new coil, leads and just fitted a new dizzy with electronic ignition but alas the problem persists.
Today I was able to pull over when it cut out, left the ignition on. I have fitted a glass fuel filter, noticed that it was empty of fuel, so gave the pump a gentle nock it immediately began to pump fuel into the filter, so I think the pump needs a device. I do have another pump a German none points one (I no alot of folk don't rate them but I will see ) so fingers crossed may be problem solved.
James k
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Re: Engine cutting out while driving

Post by James k »

It sounds like you've solved the problem then! Your best bet is probably just to fit a new set of points and a new condenser to the pump.

People here usually recommend not to have in-line fuel filters as they are unnecessary and can be a source of problems, notably vapourisation.
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