Car won't start. Electrical problem.

[DUK13Y]

This sort of relates to my other thread here, but this is more focused on the car not starting issue as I'm guessing it has a lot to do with what's wrong.

Anyway, my problem, sometimes when I go to start the car, I'll turn the key but it'll either kick over once then nothing, or just do sod all, as if I hadn't turned the key. The way I get around it at the moment is just by taking the key out and trying again. When it first started, it just needed me to take the key out once. Today though I was at the RTA getting my bike P's and I needed to take the key out about 5 times before it worked. Even then, it cranked like the battery was flat. So turned over once slowly, then again and finally started. It's also happening more frequently. At first it would happen once a month at most, now it happens maybe 1/5 times I get in the car. Today being the worst where it happened nearly every time I tried to start it, and it requiring multiple attempts to get it working. There is a very high pitched sound coming from the engine bay too which I've noticed is louder now than it was about 2 weeks ago.

Dad thinks it could the starter motor solenoid or maybe a relay that's died. I just checked the battery voltages and it reads 12.4v with the engine off, and 14.1v with the engine on. So the alternator and battery are fine, so it must be something else electrically. Any ideas would be great. Would prefer not to take it to an auto-sparky as 1: it'll cost me money, and 2: dad's a sparky, just not in automotive. so he has a good understanding of how the electrics work, but might not know what to look for exactly.

Thanks for any help.

 

[SweetWagon]

Check to see when you turn the key to start if you get a +ve trigger to the starter relay . if not could be the keyhead, if ok then check connections to starter motor and battery terminals/earths etc.. at worst you may need to replace the starter motor

 

[DUK13Y]

I don't think it's the starter motor itself as when it doesn't have the issue, it starts as normal. It's just like it isn't getting power like it should. Key might have a flat battery though? not sending the immobilizer code so that's why it wont start? Only thing is that none of it explains the high pitched squeal coming from the engine bay. It's present when you turn the car into ignition and when the car's on. Harder to hear when the cars on though.

 

[SweetWagon]

squeal could be from the alternator

 

[DUK13Y]

That's what I thought. Been doing a bit of reading and maybe a diode has died. But apparently it's just easier to get a new alternator than it is to get a new diode cluster. And it's still charging properly so I'm not sure. Such a frustrating problem.

 

[SweetWagon]

diode pack should'nt be too much or hard to install, speak to a sparky

 

[mr031]

you need to change the rectifier in the alternator if a diode goes, give a sparkie a ring and ask for a price.

 

[TMM]

Got another car you can swap batteries with? My car had similar symptoms - would either crank over slowly, or crank once followed by the dash LCDs showing random pixels and then going blank.

The battery was just on the way out. Got a new Battery and it's been fine ever since.

 

[DUK13Y]

Well my battery is reading fine at 12.4v off and 14.1v on. Took it to a sparky however and he couldn't get the car to fault, of course. However, he did recommend just swapping keys to see if the other key had the same problem, backing up my thinking of maybe the keys battery was dead and not sending the immobilizer code. New key has had no problems so far.

 

[wortus]

you need to load test the battery and see if it's voltage drops too much when it's under a heavy load, an auto electrician can do this or you can put a volt meter on the battery while your cranking it.
Key will still start the car with a flat battery in it, the battery is just to open the doors.
The fact your having to take the key in and out several times could mean there is a problem with the contact around the ignition barrell that the key contacts with.