Car Electrics Die When Turning The Ignition

[The_Silver_Slipper]

Jumped into the car yesterday and everything was looking fine. All dash lights, radio started, etc. When I tried to start it, all the electrics died. As soon as key returns to the on position, everything is back to normal... except for no engine running.

Got wifey to try to start it whilst I had my head under the bonnet and the starter does try to turn the engine, but managed about 1/100th of a turn!

Checked thw Battery and that seemed a little low at 11.8v, so I gave it a good charge. Tried again later, exactly the same.

This time I checked the voltage over the Battery and got wifey to turn the key. The voltage dropped to zero!

So I start thinking maybe the starter motor is shorting out. Spend ages disassembling everything and remove the starter. When it was removed, I thought I'd see what happens when I turn the key. Exactly the same thing! Power completely cuts out.

Next port of call is trying to find the relay for the starter. Could this have gone bad?

[crofter]

I would first have the Battery "drop tested" professionaly as a starting point, this will prove if it can manage the drain put on it by the starter

Not sure if the current fed from the start switch needs a relay as it only applies a small one to the starter solonoid which is in a way a heavy duty relay between the Battery and the starter,so if it tried to start the car then it must be working and the Battery is unable to cope

Just my two penn'oth

Del

[avensis57tr]

How old is the Battery? Sound more like the Battery needs changing think 11.8v is a bit on the low side.

[Raistlin]

It does sound like a duff Battery, you can get a voltage reading but if a cell is damaged the as soon as your draw a large current such as starting it kills it.

Can you try a replacement Battery to help in diagnostics...

[t-spiritpete]

Quote:- This time I checked the voltage over the Battery and got wifey to turn the key. The voltage dropped to zero!

Sounds like a classic case of one of the Battery cells going open circuit meaning complete failure, OR simply a loose Battery terminal. You could try jump leads (after checking the battery connections first to make sure they are secure) if the car starts ok with jump leads then you will be sure the battery has failed. Like avensis57tr says a high discharge test will also be conclusive but this means taking the battery off and taking it to be tested. I have sorted my mates Ford Transit connect van out today with the exact same problem due to a dead battery, the amazing part of this case was the battery was original and 11YEARS old!!

Another simple way to load/high discharge test a battery without a multimeter is to switch the headlights on, get someone to try to start the car whilst you see if the headlights go very dim or off completely OR you have one put the voltmeter on the battery whilst someone tries to start the engine, as in your case you will see the volts drop off to zero, battery failed!

Pete.

Edit ..... Raistlin you just beat me to it mate, I didn't see your reply until I had replied :-))

[Raistlin]

Edit ..... Raistlin you just beat me to it mate, I didn't see your reply until I had replied ;)

It's all good... :)

[The_Silver_Slipper]

Hadn't even considered it to be a failed Battery because it didn't behave like a normal Battery (headlights would go on, radio was on, dash was looking normal, etc.) on its way out, but a dead cell might explain that.

And I do have a spare Battery. Just wished I'd waited for a forum response before I removed the airbox, throttle body, inlet manifold and starter motor! :-)

All is not lost though, as I've been meaning to replace the rocker cover gasket for ages and it was one of those jobs that I was never going to get round do. I might also replace the starter whilst I'm at it, as sometimes it made a grinding noise briefly after the engine would start.

Thanks for the help guys, will let you know how it goes.

[Raistlin]

You may get away with cleaning the starter...

Why spend if you don't have to

[MikeSh]

Hadn't even considered it to be a failed battery because it didn't behave like a normal battery (headlights would go on, radio was on, dash was looking normal, etc.) on its way out, but a dead cell might explain that.

It can also be a cracked connection inside the Battery - possibly just under a terminal post if the post has been abused (eg. by excessive spanner force when tightening the clamp). The touching parts will still conduct enough for auxiliaries (headlights plus ignition is only about 10A) but present massive resistance to starting currents (probably 100...200A on a small engine) which manifests as very low Battery volts while trying to crank.

[Mike169]

Totally agree with all the diagnoses on this thread, dead cell on Battery and cleaning the shaft end of the starter motor with WD40 or similar as it probably just had a bit of dirt or just needs lubricating as the cog retracts.

Your radio and the like will work on 11.8v as of course all your accessories only require minimal current but cranking is different. I suggest you clean the starter, put the car back together changing any gaskets that you feel you want to and fitting a new decent Battery.

Regards Mike169

[crofter]

To use your own words Mike, totally agree with your last post except for the lubrication bit.

This I have done in the past on breakdowns as a quick fix at the roadside but always stressed that was all it was and would need attention as soon as possible.

This would usually be on the old type starter where the pinion was engaged by the inertia force of the starter motor

When bench testing the type that has the pinion thrown in ,with great force, by the solonoid I would then again question the need for oil if the pinion shaft is cleaned.

This is,of course, only my personal o-pinion (get it) and in no way suggests that other info is wrong

Del

[t-spiritpete]

Plus 1 on that one Crofter,

any lube except for maybe dry silicon spray (which isn't really needed) will just attract dust etc and lead to more problems.

I got your little pun, very good ...... is that just a starter for ten .

Pete.

[Phil01]

Just fit a new Battery, end of