NeilPuddy

2010 fortwo cdi starting intermittently

7 posts in this topic

Hi all. I hope someone can give me a bit of advice or has seen this fault before. Just after Christmas the car failed to start after we had been using it and we had to be recovered to my garage. With the key inserted everything appeared normal with the cluster display normal and various relays clicking as usual. All appeared normal just no start up. The garage found a fault code related to the immobiliser which they cleared and the car started no problem. Then about 10 days ago the car was in the garage for a drive belt replacement and wouldn’t start when I went to collect it. The garage did a bit more fault finding and there was no voltage at the starter motor. There was an immobiliser fault code again which was cleared and subsequently the car started- 12volts was then at the starter motor as expected. Tried to start and stop the car a few more times and didn’t fail so I took the car home. Used it at the weekend and ended up getting recovered home again as the car would not start and wouldn’t bump start either. At the moment the car is on my drive not doing anything. All the lights and relays appear to be normal? Has anyone seen this before or had similar. Am now awaiting an auto electrician to come and look but any ideas would be greatfully received! 

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Is it damp inside? Feel under the carpets or lift the carpet over the battery and look.

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No damp at all! Appears to be very dry around the battery and Sam unit is in very good condition.

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Hmm.

When you say no voltage at the starter do you mean no start signal or no voltage? Thick wire or thin wire.

 

On the right side of the engine under where you pour oil in there is an earth cable between the tridion and the engine. Check that. I don't mean just look at it, pull it and rive it and possibly take it off and replace it anyway because they are proper shite.

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I’m taking it that the garage means no voltage on the thin wire as that comes from the Sam unit? I can’t get under the car myself as don’t have access so am relying on them. I should be able to check the earth though so will have a look at it. Thanks for your help.

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That earth wire is a braided garbage wire as mentioned above, usually they disintergrate in your hands when touched or pulled.  The signal wire for the starter is another bad connection wire that is a spade style that does come loose and the spade requires simply squeezing tight again and maybe the spade connector cleaning up and add some grease to it to slow the corrosion down next time. 
Did you take your SAM down or just peek at it?  IF you didn't take it down do so and then open it up to peek very carefully at the circuit board for cracked cold solder joints. It's a common problem due to over heating of the pins  for whatever reason. The SAM can also get water damage on the board creating white corrosion that can be tooth brushed off using vinegar and then resealing the board after carefully checking  the pins etc.
I don't have the pin out in front of me but you should be able to figure out which wire from the connectors is the signal for the starter solenoid to check to make sure it's sending 12 V to the starter, then if you get under vehicle or in through the righthand side wheel well to get at the starter....good luck with that, it's a real pain to see let alone test. IF you are skilled with a long rod or wire or coat hanger you can reach the spade connector to test from the top looking down into the engine bay. Just wrap some electrical tape around rod or wire etc so you do not short it out trying to test for 12V.   All this is suggested knowing that you could make things worse than they are now if you short somthing out. These cars are very sensitive electronically speaking.  Be careful 

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So fingers crossed it looks like the car is fixed. Mjolinor mentioned checking the earth on the engine and I had a look and wasn’t overly pleased with it. Looks like it had been stretched and crushed slightly which I am putting down to having the water pump replaced before Christmas. The garage told me they had to drop the engine on one side to get access and the timeline for the issue ties up with this. Have fitted a universal part from Halfords today and it has started on the button since. Not overly pleased with the quality of the new earthstrap but for a fiver I wanted to see if it would fix the issue. Have just received a Smartmod kit to replace both the battery and engine earth and these are much more substantial so will fit these Monday. Would just like to say thanks for the advice all! Will definetly be looking on here again for any future issues!

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