General punto starting problems!

[Chris-blk2000punto]

Hey again guys, another question about the dam punto. Basically the car only starts sometimes and I have no reasons why. I Replaced the battery a while ago coz the old one was completely gone. I dont think its the alternator coz the battery is reading a constant 12.5 volts when the engine is off and 14.5 when on, when it does start i have disconected the battery and the engine keeps runnnig. what could this be? just the cold weather you reackon? any fixers to help it along or is there anything i need to check? thanks for the help punto mk2 2000 1.2 8v

 

[Punto.Power]

All the things you have said sounds normal, it could be anything to old spark plugs needing changed to a faulty sensor, maybe even the starter motor is acting up or the fuel pump.

 

[Chris-blk2000punto]

when i jumped it from my VW polo it started 1st time, what signs would i get it it was the starter motor and how do i exactly check it and also the alternator? i disconected the battery when the engine was on and it stayd on so does that mean the alternator is fine? thanks

 

[Punto.Power]

If its starting ok with the jump leads then i wouldint say its the starter motor, could be a faulty alternator not keeping a charge over night, but then again if you disconnected the battery and it still ran ok i wouldint think it be your alternator, your battery sounds healthy with the reading you got from it you could try reading it again and this time put your lights on full and heaters as well if it drops below 12v i would say your alternator is either nackerd or there is something else wrong.

 

[Chris-blk2000punto]

any1 know what that something else is?

 

[dan_in_darlo]

could be the fuel pump or starter motor when my went on my punto it was starting up ok sometimes then others was really hard to turn over but would start from bump start and jump leads try changing the starter see if that dose anythink

 

[The Sultan]

firstly you should never remove the battery terminals wile the engine is running

this will damage the alternator and can cause ecu failures due to power surges and the sparks near the battery that has just been charging will light hydrogen gas and blow up covering you in acid and cause you a great deal of personal injury

your very lucky to have gotten away with that

the readings you have are fairly good so the alternator is fine

a fully charged battery should be 12.76
a half charged battery will be 12.4

could be as someone has said a faulty starter motor does it turn over quickly or quite slowly if the starter is drawing to much power wile cranking it will cause the engine ecu to turn off

just check the voltage wile you start the car it should not drop below 9v