1uz flattening battery extremely fast. Drop from 14.5 V to 12v in 10 minutes.

[desty]

Hey guys my car has developed an electrical gremlin. From a full charge it reads 13.1 volts, increasing to 14.5 volts when the engine is started. ( I assumed this meant the alternator was working) after about 10 minutes of driving the car develops mad hunting idle and eventually just stops. On one trip I was able to limp and sputter the last few hundred meters home by keeping the revs high, dropping the revs resulted in immediate engine stop. It's got adaptronic ecu and microtech ignition if that helps.

Theories?

Thanks.

[RA35GT]

Check for any shorts in wiring?
Do you have a multimeter to check for current drain in the wiring?
Does it still drop charge with ignition off?

[desty]

Electrics aren't my strong point. I don't know how to check for shorts, yes I have a multimeter, no it doesn't drop voltage with the ignition off.

thanks.

[dori81]

if you near an auto electrical work shop take your battery out charge it over night take it to them and ask them to load test it, if that's ok put the battery back in the car and check at the alternator to see if your alternator is charging so the black lead to earth and the red lead to the positive terminal on the alternator and you'll get a more accurate reading then putting it on either terminal of the battery if its not charging at 13.9-14.5 then your alternator is more than likely at fault and will have to be either replaced of overhauled and a auto electrical workshop. also while the batteries fully charged pop your bonnet make sure all your doors are shut and the keys are out of the ignition and do a current draw check set your multimeter to read amps then swap your positive lead in the multimeter into the A (amps) set it to 10 then take your negative terminal off and put one of the multimeter leads on the battery terminal and one on the negative lead its you want a reading not much higher than 0.02 amps (its important nothing else is running like interior lights cause doors are open ect cause it will increase the reading leading you to a false diagnostic

[desty]

Also just remembered that the battery had really bad deposits built up on the earth terminal when I got the car, but it's never skipped a beat until now.

[rxbenny]

get your battery tested/buy a new battery and clean the terminals with hot water and bicarb.

[4th surf]

Does it still have the stock ignition coils on it?

[desty]

Thanks guys I'll try out some of this stuff as soon as I work out how to use a multimeter beyond measuring voltage.

I cleaned the terminals and treated them months ago, there's no visible deposits anymore

I believe it still has the stock coils.

[4th surf]

Replace them and your problems should end. Particularly the one that is mounted on the L/H cyl head above the A/C compressor

[desty]

Really? It drives normally and has no A/C. I was following that other thread with your coil issues and don't recall any mention of drained batteries? Though I was only skimming it.

[4th surf]

Automotive batteries only last for about 24 months at the best of times so the battery is probably a bit sad with a crook cell causing the corrosion on you neg terminal. That happens on any car. Now the battery drain will be nothing to do with your engine conversion or what engine management system you have. What else do you have in there? Big stereo? Super duper alarm?. I have one in the shop ATM that we converted 2 years ago that keeps killing batteries. I unplugged all of our wiring (wired 1U into the same loom as original engine harness, copied pinouts if you will) And battery still drained. Disconnected the amp in the big arse stereo system that got fitted by Alberts after and the problem has gone away. The stutter in your engine will be that coil A/C hooked up or not as it is the one that soaks the most heat. Veales stock them and they aint expensive, but like your socks change both

[DazbaVBz]

Hey man, sounds more like a alternator is on the way out, brushes could be starting to get low, or a reg is playing up, if its starting up ok id say the battery is ok, with a multi meter on cranking you should see around 10V at the battery or more, when its idling you will have low alternator charge around 13.2V under throttle you will see 13.7V to 14.5V this, is only a indication, if your alternator not charging while being driven with fuel pumps, thermos etc, it will quickly drop your battery voltage down, is there a red battery light on the dash - was this hooked up in the conversion proper ally, if the brushes are on there way out or a reg issue, is where i would be starting.

[stradlater]

The reg played up in my 1uz alternator - they are easy as hell to replace because the regs are the same as in a bunch of other cars.

Give it a crack?