Problems with car - Suzuki Jimny (1997)?

Recently, my car has been having problems. It's a fairly old vehicle but has been well maintained over the years and never had problems until now. Here goes........

About a month ago, I left the lights on while parked, the battery was flat and the car wouldn't start. A friend of mine gave me a jump start and the car worked fine for a month or so. Then one day on my way to work, the car started to shake and rattle as if it was stalling with not enough revs, but this was whilst doing 30mph approx on a main road. I down shifted to a lower gear but this had no effect, the car conked out. It would not start, as if the battery was once again flat. A friend of mine gave me a jump start and the car worked fine for another week or so. I bought a new battery as I thought this may be the issue, but didn't fit it, just left it in the car with me fully charged.
I then took it to the garage for MOT and service, they found an issue with the front exhaust system and replaced, but did not identify any further problems. 8 days later, after a 20 minute journey, the car stalled and when I went to start up again, it was as if the battery was flat... again. I left the car in a lay-by and walked to work. when I returned to the car at lunch-time, the car started first time and worked without problems for a further 2 days. In which time, I filled up the oil, radiator water, antifreeze, as I thought the issue may be the engine overheating rather than a self charging battery problem.

Until this morning when the car (as before) started to shake and rattle as if it was stalling with not enough revs, but this was whilst doing 30mph approx on a main road. I down shifted to a lower gear but this had no effect, the car conked out. It would not start, as if the battery was once again flat. Once again, I jump started the car from the new battery which I bought and the car started and I made it to work.

Now i'm really confused and have no idea what the problem is. The car conks out whilst driving and then won't start again as if the battery is flat, but I always thought that the battery wasn't necessary once the engine is started so don't see why the car stops.
I need a mechanic like Sherlock Holmes or the equivalent of Dr House in the car industry to give me some advice.

Notes**
-The engine temperature gauge on the dash showed at half level when the car cut out (between cold and hot). Over the past couple of weeks, I have noticed some quite erratic temperature levels whilst driving, on one journey the needle went above "hot" and was off the scale. It's currently freezing where I live and snow everywhere.
-On one of the days when a jump start was required, I drove home that evening and connected a battery charger. The battery charged for about 30 seconds and then said it was fully charged.
-There is no hot air coming from the heating vents within the vehicle for the past couple of weeks, cold air blows fine.
-Sometimes, there are large plumes of thick white smoke coming from the exhaust, this has been for the past couple of months now before any problems were experienced otherwise. This is also intermittent and has occurred before and after the front exhaust system was replaced by the garage.

Please help

replace the battery and check the altanator , also check the plugs
if the problem comes back it could be an ecu fault caused by jump starting

What your problem is mate is a fault with the charging circuit. More than likely it will be the alternator. Whats happening is the alternator is intermittently not charging, you car will run fine depending on electrical load for 5 min or so, until the battery voltage drops below around 8 volts. At this point your ECU will fail to recive and send signals to certain components like the coils an crank sensor, therefore it will cut and stall like you have described. When you try and restart the car you get a flat battery symptom. Cause that is what you have. But as you battery is In Obvious good condition it is what you call 'recovering'. Basically because the drain is at a such a rapid rate, when electrical load is switched off the battery will recover back to 12 volts again when rested.

Eg, when you crank your car in a none start condition you battery voltage will drop down to 10 ish volt and then down to 9 ish. When you stop cranking after a few seconds it will be back up to 12 volts again. (recover) good battery !

I have seen this many times on different vehicle matey,

Intermittent alternator fault.


Steve.

My guess would be a dodgy earth...
Check all your earth straps, take them off clean them up and reconnect. Easy and free!

Otherwsie charging fault, just to check you say large plumes of white smoke, are you loosing any coolant?

My 04 Jimny is puffing a bit of white smoke (steam) lately, this is due to the cold weather and sudden drop In temp.

The charging fault I described will also effect all your gauges, dials etc, will make the car do strange things.

If its that intermittent wire a multi meter upto the battery and into the car temporally for testing purposes. You will see the meter dropping voltage from battery when the fault accrues from 14.5 down to about 8v and that when dials and gauges will start to go haywire !

Steve.

Hi everyone, many thanks for all the responses so far

The car broke down again twice on the way to work this morning, wouldn't start again via ignition. Luckily, both times, the car was still rolling at the time so I stuck it in 2nd gear and hit the accelerator pedal and it kept going (bump start).

I guess my best bet from the sound of things is to replace the alternator. I myself am not a mechanic, but quite handy when it comes to tools and building, etc.
What do you think? Should I buy the alternator and try to fit myself or just take it to a garage and pay their extortionate fees? (there are plenty of youtube guides how to do so)

I have been looking around and found a few used ones on ebay such as tinyurl.com/6p7c6vl , not sure this is definately the right part. Mine is a 2000 model Jimny JLX.
This is ofcourse with fingers crossed that it is the alternator at fault :S

Please let me know your thoughts gurus