Quick question needs quick answer

[Rigbyy]

A week ago my car failed to start, which ofcourse drained the battery but I got a bump start, got it home and checked out the battery and if the alternater was doing anything, gave it a charge overnight and it started straight away and has been as normal since then untill today after work. Try to start it and it does one pathetic attempt at turning over and then the fuel gauge and temp gauge fly to the top and back down and the trip resets, although the radio doesnt. Got home, 30ish miles, got the multi meter out again and its showing 12.6V with everything on and then 12.4V with the car off, the last time it was showing 13.2 with everything running once I charged it for a bit.

My hunch is that the alternator is charging the battery but the battery cant hold its charge?

[Paul Drawmer]

what's the rush?

[mybrainhurts]

Earth...?

[Jonnas]

Quick! Get a new battery!

[carmonk]

I think it's the -

doh, too late

[Rigbyy]

Had a small feeling it could be a dodgy earth or a short somewhere.

Ill have a quick look at the main ones.

[the_bear]

last time i had the same thing happen to me it was the alternator. 12.6v with everything on doesnt sound right, it should be around 14 (i think)

[base]

my guess on information provided is alternator is faulty.

[Flintstone]

i don't noe wot the problim mate bee but why not check the batree flooid lvl and wile ur their check the terma.....turmenu........termanellls.........connections and also the fanbelt it mite bee lose or sliping is it sqeelin or making a noise are the lites workin and are you startin it with everthing switched on like fan and radio and lites are the leccy windows wurkin okay and im runnin out of stuff to tipe how the hell do ppl rite in txt and without punctuation all the time i dunno how they do it innit.

[Rigbyy]

Started the car with the battery at 13.2V, started fine, turned all the lights, heater, rear screen etc on and the reading was steadily inscreasing, took it for a little drive and its started fine after. Just like it did last week.

[Jimmyarm]

base said:

my guess on information provided is alternator is faulty.

This, your alternator is knackered.

Charging your battery up out of the car will give it enough power to drive for a while and start a couple of times.

At idle, the reading across the battery terminals should be >14v

[Rigbyy]

mybrainhurts said:

Earth...?

Seems to be this.

Theres now a load more symptoms with my car, including heavy jolting while accelerating, possibly from a different issue, revs fluctuating when the peddle is held constant. Although now when the ignition is turned on the battery light flashes, the speedo jumps up to 10mph and down repeatedly and a ticking noise which sounds as though its coming from the ECU. Going to try another ECU reset and see what happens.

[thewhooshparrot]

Battery should read 12v /1.5v at rest,and 14.4v with engine running after a rev,no load,when load applied it should drop a tiny bit if at all,id replace alternator,with no charge it will act up,and as said above when you charge the batery it will be ok for a while until the low charge gets the battery down again.

[Rigbyy]

A quick video to show my problem.



Click to view.

[john2443]

Go to a decent car spares place (ie not a chain shed type) or your friendly local garage and ask them to check - they'll have a meter that puts load on the battery and will tell you in 2 mins if it's batt or alt. You can't tell using a standard multimeter.

Yes, voltage whould be nearer 14 than 12 when it's at full charge.

[FreeLitres]

I liked the bit in the video when you went beyond the red line!

Very quiet engine though.

[Rigbyy]

FreeLitres said:

I liked the bit in the video when you went beyond the red line!

Very quiet engine though.

Stunned even myself I must admit!

[Rigbyy]

Just thought Id update to say its fixed and being dropped off later, the cause was the starter motor and earth cable which have both been replaced.