Charging/starting problem Mk2

Aerodynamica · Post by **Aerodynamica** » Mon Feb 09, 2009 4:16 pm

Hi all, I realise there are some threads that are asking about charging etc already so I don't want to hijack them.

Problem I got yesterday morning and this morning is that the battery seems to lose all will to work after initially bringing the starter to life pretty strongly.

I usually start up on LPG gas but at around zero degrees it seems to have found its limit of cold starting so it didn't catch right away then the starter went slow and didn't recover.

Got a jump start and the starter was initially slow but improved and it started on petrol.

This morning I started on petrol but at first the starter was fast and before the engine caught it slowed right down so I gave it a rest for 20 sec and restarted - fast at first then got slower - I thought it was going to be a repeat of the previous day but suddenly it caught and ran so I was lucky (the beauty of electronic ignition)

I don't have a multimeter and in the light of the fact that the starter runs quickly then slows down is there any obvious symptom there that anyone knows is 'battery' or 'starter' or something?

I've also noticed the battery light glows slightly at night - and pulses with the indicators

- any ideas? if it's some short circuit how do you go about tracing it?

DLM · Post by **DLM** » Wed Feb 11, 2009 6:44 pm

I've also noticed the battery light glows slightly at night - and pulses with the indicators - any ideas? if it's some short circuit how do you go about tracing it?

I'd discount these fiirst. Your battery is not being charged by the alternator when the battery is under load (lights), the battery is not accepting charge, or the charge from the alternator is marginal. I'd have a look at the alternator belt tightness first, then take voltages across the battery in the following conditions

(1) at rest (gives charge of battery only)
(2) with engine on (action of alternator should show as extra voltage across battery )
(3) engine still on, with lights (to show effect of load).

There is a possibility of poor earth somewhere: I had a similar problem because

(a) One alternator brush was so worn as to be ineffective
(b) Connections needed to be remade to counter the effects of corrosion on terminals etc.
(c) There was an earthing problem on the ignition switch

Fixing a and b restored function, while (c) got rid of the faint glow at night.

Vanny · Post by **Vanny** » Wed Feb 11, 2009 7:11 pm

DLM, can you expand on c) There was an earthing problem on the ignition switch ? Sounds interesting as i suffer similarly

Aerodynamica · Post by **Aerodynamica** » Thu Feb 12, 2009 8:24 pm

Thanks guys I'll find a man with a multimeter.

I'm also interested in point (c) - was the problem related to the ignition barrel as a unit or the wiring leading to and from it if you know?

DLM · Post by **DLM** » Fri Feb 13, 2009 5:21 pm

Hi Vanny. That earthing problem on the ign switch - well, I had some problems with an intermittent connection somewhere in the upper part of the ignition switch/loom assembly.

This really hit home round about MOT time in March last year when the ABS light was staying on after startup. After tracing most of the ABS wiring through and trying all the diagnostics I could, I eventually found that the problem related to the precise position of the switch loom under the column shroud. Pressed for time, I tie-wrapped it into a stable position and then replaced the switch later. Symptoms had included:

(1) Very occasional engine cut-out at low revs (this prompted me to look at the switch as sometimes restart was affected by minute changes in the position of the key)

(2) Very light glow of the battery light with the lights on - more noticeable at motorway speeds.

Tom, the previous owner of the car, had pointed me in the direction of the ignition switch after consulting the circuit diagram when I described the fault in (2) above

velosolex50 · Post by **velosolex50** » Fri Feb 13, 2009 10:47 pm

fixing a poor earth where the engine earth lead bolts to the battery holddown bolt worked wonders for my slow starter, despite no detectable voltage drop with a multimeter, surprisingly.

Way2go · Post by **Way2go** » Sat Feb 14, 2009 2:34 am

velosolex50 wrote:fixing a poor earth where the engine earth lead bolts to the battery holddown bolt worked wonders for my slow starter, despite no detectable voltage drop with a multimeter, surprisingly.

Not really surprisingly as a multimeter draws next to no current but the starter draws lots more for the poor connection to show up.

velosolex50 · Post by **velosolex50** » Mon Feb 16, 2009 7:51 pm

Voltage checked while cranking, so should have seen something.Probably a crap connection to the meter too. Still, problem solved by sorting the earth!