03 Micra K12 - Cranking but won't start when Engine Cold - Garp242

[Garp242]

Sun 10 Jan 2021 12:59 03 Micra K12 - Cranking but won't start when Engine Cold - Garp242

This car just won't start when Engine is cold !! It will start if I spray petrol into Air Filter ... but that's not something I'm comfortable with !! I think it is down to a faulty sensor that is sending incorrect or NO signal to ECU. I've replaced the Coolant Temp Sensor but that made No difference. I THINK there is only one on the K12 - maybe someone on the Forum can confirm that ?? I now suspect the MAF Sensor ( the one on top of the Air Box, 4 terminals & 1 bolt ) may be faulty. If I disconnect it with the engine running - the engine continues to run. I'm informed that the engine should cut out when this is disconnected ?? Again, maybe someone can confirm or dispute that. I'm also pretty sure that it's a "cold start enrichment" issue - but what's causing it , I'm not so sure of !! At ALL other times it runs & starts perfectly !! All suggestions welcome ...

 

[Mach1]

Start by cranking the engine and if it does not start remove the spark plugs (as I am guessing it's a petrol model) and check the plugs for petrol residue, whilst you have got the plugs out crank the engine and check for good arching of the 4 plugs! this will check then, that either you have a fuel supply issue or a electrical issue, or if the plugs are in poor condition?

 

[Garp242]

Start by cranking the engine and if it does not start remove the spark plugs (as I am guessing it's a petrol model) and check the plugs for petrol residue, whilst you have got the plugs out crank the engine and check for good arching of the 4 plugs! this will check then, that either you have a fuel supply issue or a electrical issue, or if the plugs are in poor condition?

Since the end of the cold nights & heavy frosts, about a week ago, the car has started every morning without any trouble. I think it is a "fuel enrichment" issue possibly caused by a faulty MAF sensor. The engine runs even with the MAF disconnected - I'm advised it should cut out. Gonna replace that first and see if it is cured. Have new set of plugs ready to fit either way ...