car wont start

helpimcrap

helpimcrap

helpimcrap

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Joined
13 Jan 2004
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Leicestershire
mates car wont start.

renault megane 1.6 petrol on about an R plate. has an immobiliser/coded key i think.

basically when turning the key the lights on the dash flicker, the clock resets to 00:00 and the radio loses its tune.

battery is good, 12.4v turned off, 14.4v when running. we can get it running first time every time when its jumpstarted.

i'm guessing its the ignition barrel playing up as it drops to 0.1v when the key is turned and it doesnt even click on the starter. when jumpstarting it, it goes down to 1.0v which shouldnt make any difference unless its because my car was pumping extra volts in? 14.3 v 12.4v no his car....

what you guys reckon?
 
It could still be the battery. Have you swapped it out? The drain on a battery during cranking is immense and if a cell has dropped it, during cranking it may just not have enough juice.
 
Try measuring the voltage across the battery with some load on, eg lights/main beam, or just trying to start it,

fairly sure you'll find that the voltage will drop from a seemingly fine 12.4v to sub 5-6v, basically battery is dead, can't remember the exact term but it happens...

EDIT: Reading again sounds like that's whats happening, new battery will almost definately fix it :)
 
helpimcrap said:
mates car wont start.

renault megane 1.6 petrol on about an R plate. has an immobiliser/coded key i think.

basically when turning the key the lights on the dash flicker, the clock resets to 00:00 and the radio loses its tune.

battery is good, 12.4v turned off, 14.4v when running. we can get it running first time every time when its jumpstarted.

i'm guessing its the ignition barrel playing up as it drops to 0.1v when the key is turned and it doesnt even click on the starter. when jumpstarting it, it goes down to 1.0v which shouldnt make any difference unless its because my car was pumping extra volts in? 14.3 v 12.4v no his car....

what you guys reckon?
Click to expand...

batterys had it or needs a good charging.

Fog
 
The battery sounds fine to me, voltage looks good.

Short somewhere? Good luck trying to sort it as electrical problems are usually a bitch to sort!
 
Battery's probably been drained too low, can cause damage if it's lead acid, also check the battery level and the earth strap.

Symptoms (Vdroop) also match a bad connection somewhere.
 
Could very easily be the battery. As suggested, swap it out, or put a load across it and see what happens to the voltage.
 
Yea, internal short in the battery. Exact same thing with my Dad's Merc now and then - completely refuses to start, although everything else is fine. Jump it and off it goes.
 
something like this happened to a friend's clio the other day. it drove the 30 miles to work, got there, parked and then he went to put it in another space. turned the key and the starter would only click. everything else seemed fine (voltagewise)

not sure what hes done with it since (we've been using my car to get into work) my bet is that the starter motor had popped its clogs and was draining the battery when you tried to crank it
 
Exactly the same thing had happened to my car about 3 weeks ago. Turned out a cell had died inside it.
 
Are you measuring the voltage directly accross the two battery posts? If so then it certainly sounds like a dead battery.

If not then you could have a poor connection on one side of the battery, and it's usualy the ground cable. Carefully check the earth cable where it clamps to the battery and at the other end were it will bolt onto the body. Move the cable around to make sure it is tightly bolted down and the crimped terminations are sound. If nothing have a good look at the positive cable.
 
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