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My sister has a nice first generation Nissan Micra 4-speed automatic (I think it's the naturally aspirated, non-electronic carburetor version) . However, when starting it from a cold start (not necessarily cold weather, just when it's not used for a couple of hours), it has a problem with keeping the engine running.

It sometimes does not start until you 'pump' the accelerator before ignition. Whether that's necessary or not, it will have a very low RPM after ignition, and will cut out the moment you touch the accelerator, also in neutral. This problem will go away after maybe a minute, after which the car will function as normal, and it's genuinely fun to drive (don't judge...). What could be the cause? Is there an economical fix available for possible causes?

Perhaps related or unrelated: when filling it up, you can only do so very gently, for else it will 'block' just like when the tank would be full - reportedly it's due to a blocked air tube.

  • The first thing I would do is check if the coolant temperature sensor is functioning well. You can check it's resistance when cold, often you can find tables of correct resistance values matched to temperatures in service manuals to compare. – I have no idea what I'm doing Apr 15 '16 at 12:21
  • Its non-electronic carb, so it likely will not have a CTS, just a sender for the gauge. – rpmerf Apr 15 '16 at 13:23
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Not familiar with your vehicle/engine specifically, but familiar with carbed engines in general.

I would think the #1 thing to look at would be the choke. Pumping before starting a carb vehicle is normal. It gives it a squirt of fuel and sets the choke. The low RPM indicates that the high idle is not set, which likely means the choke is not set also. There should be a spring on the side of the carb that sets the fast idle and choke when cold.

  • Thanks. I was dimly aware that pumping the accelerator was normal for carbed engines, but I figured that I might as well include it for completeness. I will look into the choke then and see what I can do :) – Sanchises Apr 15 '16 at 15:18
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initially press the accelerator slowly to the floor. Then wait a few seconds before cranking. Pressing the accelerator slowly uncocks the auto choke without injecting fuel via the accelerator pump circuit, (this gives the rich mixture during slow cranking required for starting, without flooding) . Then next, fire up the engine, let the car idle, and don't try to drive for about two minutes. If this does not work, get someone to check the operation of the automatic choke, because it is not working as advertised. Your sisters engine is a carburetted engine, therefore the mixture and idle speed are set manually by a good mechanic, and if a smooth idle and transition is unobtainable by a qualified mechanic,this generally require a carburettor tune up kit due to wear over time. After this, if your engine is in reasonable mechanical condition the car will run fine.

Cheers, Hutch

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