mini needs jump starting every time
Discussion
Hi All,
I'm new here as I've just bought a Rover Mini Sprite 1995
I've just driven it home and had great fun on the country roads, bouncing around hitting my head on the ceiling.
However, it needs jump starting every time, which is a bit inconvenient. When I turn the key it makes absolutely no sound (or sometimes I hear the relay clicking in and out as the battery voltage is just too low to hold the relay on), but when connected to another car it starts no problem, so the starter motor is clearly fine. Apparently the battery is new, so that shouldn't be the issue, and when the engine is running the lights and other electrics work no problem, so I think the alternator is working. But that's as far as my technical knowledge goes and I don't know how to diagnose it further... any suggestions?
Cheers
Stu
I'm new here as I've just bought a Rover Mini Sprite 1995
I've just driven it home and had great fun on the country roads, bouncing around hitting my head on the ceiling.However, it needs jump starting every time, which is a bit inconvenient. When I turn the key it makes absolutely no sound (or sometimes I hear the relay clicking in and out as the battery voltage is just too low to hold the relay on), but when connected to another car it starts no problem, so the starter motor is clearly fine. Apparently the battery is new, so that shouldn't be the issue, and when the engine is running the lights and other electrics work no problem, so I think the alternator is working. But that's as far as my technical knowledge goes and I don't know how to diagnose it further... any suggestions?
Cheers
Stu
See what the battery voltige is with the engine off should be 11-12V. Then start the car and see what you get (13V+). If you do not see a jump 1 or 2 volts the alternater or cabling is duff. If it is ok then disconnect the battery when you stop. Reconect the battery when you go to start. If it starts ok then you have a drain on the battery when the ignition is off. If this is the case check the cables from the battery to the front, connections and earth pints. If the battery is dead it could be just a duff new battery. Hop this helps
Just to confirm what has been said really.
1. Check the battery voltage which should be c.12 V after charging and check the charging voltage which should be around 14.5 V at around 2000 rpm.
2. If that comes up OK, check the battery earth and the engine-to-body earth. In fact, if in doubt, run a jump lead from the cylinder block, say a head stud, straight to the battery negative terminal as a way of checking for a bad earth.
3. If the earths are OK check the starter motor +ve connection. I had a loose +ve connection recently and that prevented it from starting/turning over properly.
4. Finally, if all else fails, check for a current drain when everything is switched off by taking the earth right off and putting an ammeter across from the negative battery to the body. Some cars do drain down and fitting a master cut-off switch in the earth line near the battery can be a good solution if the drain-down can't be identified.
I hope this helps.
1. Check the battery voltage which should be c.12 V after charging and check the charging voltage which should be around 14.5 V at around 2000 rpm.
2. If that comes up OK, check the battery earth and the engine-to-body earth. In fact, if in doubt, run a jump lead from the cylinder block, say a head stud, straight to the battery negative terminal as a way of checking for a bad earth.
3. If the earths are OK check the starter motor +ve connection. I had a loose +ve connection recently and that prevented it from starting/turning over properly.
4. Finally, if all else fails, check for a current drain when everything is switched off by taking the earth right off and putting an ammeter across from the negative battery to the body. Some cars do drain down and fitting a master cut-off switch in the earth line near the battery can be a good solution if the drain-down can't be identified.
I hope this helps.
So... it started (twice) last night after charging for 4 hours and then again this morning and afternoon without any subsequent charge, so it's retaining its charge ok.
I still don't have a multimeter so couldn't check the voltage, but I did a basic test of turning the headlights on with the engine idle, then revving to see if they brightened... they didn't change brightness. So I presume that means that it's an alternator problem? What powers the spark plugs... is it the alternator or a higher-voltage coil?
Thanks for the input guys
I still don't have a multimeter so couldn't check the voltage, but I did a basic test of turning the headlights on with the engine idle, then revving to see if they brightened... they didn't change brightness. So I presume that means that it's an alternator problem? What powers the spark plugs... is it the alternator or a higher-voltage coil?
Thanks for the input guys
Sounds like the alternator not charging, but why has the charge warning light not come one?
You need to measure the charge before buying a new alternator.
Plugs are driven from the coil, coil is driven from the ignition, ignition is powered from the battery and battery is charged by the alternator.
You need to measure the charge before buying a new alternator.
Plugs are driven from the coil, coil is driven from the ignition, ignition is powered from the battery and battery is charged by the alternator.
stu
does the red alternator charge light come on when you turn the ignition on?
it should then go out once the car is started and reving above 500-1000 rpm.
it may flicker/glow below 500 rpm if there is a lot of electrical demand.
if the red light does not come on when you turn the ignition on, then you need to check the bulb and the feed as this will be causing your problem - the alternator needs a 12v feed to excite it to start charging.
if you search back, there is a thread about alternators and checking them.
does the red alternator charge light come on when you turn the ignition on?
it should then go out once the car is started and reving above 500-1000 rpm.
it may flicker/glow below 500 rpm if there is a lot of electrical demand.
if the red light does not come on when you turn the ignition on, then you need to check the bulb and the feed as this will be causing your problem - the alternator needs a 12v feed to excite it to start charging.
if you search back, there is a thread about alternators and checking them.
It could just be that the fan belt needs tightening. I had this recently on the way to the Sunday service in my classic mini - we ran out of electricity in Kent!
The charge light didn't come on (what I mean is that it came on when I turned on the ignition, and went out when the engine started, but the battery still went flat). Tightening the fan belt (plus a jump start with the spare battery I had with me) got us going, and the problem has not come back.
The charge light didn't come on (what I mean is that it came on when I turned on the ignition, and went out when the engine started, but the battery still went flat). Tightening the fan belt (plus a jump start with the spare battery I had with me) got us going, and the problem has not come back.
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