Electrical Issue: Drop In Voltage On Startup

[rawd]

hi all,

have an issue that has been pissing me off ever since i bought the car - hope there's someone out there that might have an idea of how to fix it cos i can't afford to see an auto-elec right now.

on start-up when i go to reds, sometimes it will go straight to 12v and crank first go (most of the time needs a bit of gas but i think that's cos my car is running rich)

other times when i go to reds, voltage will drop < 10, lights dim, fuel pump will struggle to prime and starter motor struggles with clicking noise and i have to get on the gas or keep turning it over to get it started. usually if i keep trying to turn it over a few times with the key the volts will eventually rise back to around 12 and it will start. each time i turn the key i hear a single click - not sure what this sound could be but it strangely sounds like its coming from the door.

alternator is pretty new - charges at 14.2 when running. battery has been tested by the place i bought it and it's fine. could be my alarm and the clicking sound is the keyless entry? bad ground somewhere? battery is actually screwed? i have no idea but would like some ideas on how to diagnose so i can either take to auto elec for a quick fix or fix it myself.

thanks in advance.

rod

[rawd]

more info: voltage drop doesn't just happen on start-up. sometimes when i get out of the car and press the keyless entry the car won't even have enough volts to lock all the doors. i usually have to either keep trying or put the key in the ignition and crank to bring the volts back up.

shit - i know this could be one of a million things but i appreciate any input

[Wacky Dee]

to me it sounds like an issue with the alarm .. bad ground or something like that. Who installed it for you? If you know who installed the alarm take it back to them to fix it.

[danielr34]

To me it still sounds like a battery issue, even if a battery shows 12V on a multimeter doesn't mean it is a good battery, does it give you the most problems in the morning? because that is when batteries are at their lowest, try to jump start the car off another car to see how it goes. If the problem is still there, I would be looking at the starter circuit and would suspect excessive current draw somewhere there. Sometimes starter motor solonoids get sticky and don't always throw (causing a clicking noise).

Before anything else I would be looking at the battery. The average battery should be change every 2 - 3 years and the number one cause for car starting problems is battery power. What size is the battery? check the Cold Cranking Amps (CCA) on the label. The higher the better. Check the battery voltage with engine off, a good battery should read about 13.8V and watch the multimeter while starting the car to see what it drops down to.

As for the alarm it sounds like it is struggling to get power, now alarms either have power or they don't, if it is struggling to lock the doors then this leads me back to battery power or lack of power. It wont be a bad investment if you bought a new battery because this will benefit all electrical components in you car from ecu to sound system (especially if running subwoofer/s).

Based on what you have said these are my thoughts from my experience.

[Carbon 34]

To me it still sounds like a battery issue, even if a battery shows 12V on a multimeter doesn't mean it is a good battery, does it give you the most problems in the morning? because that is when batteries are at their lowest, try to jump start the car off another car to see how it goes. If the problem is still there, I would be looking at the starter circuit and would suspect excessive current draw somewhere there. Sometimes starter motor solonoids get sticky and don't always throw (causing a clicking noise).

Before anything else I would be looking at the battery. The average battery should be change every 2 - 3 years and the number one cause for car starting problems is battery power. What size is the battery? check the Cold Cranking Amps (CCA) on the label. The higher the better. Check the battery voltage with engine off, a good battery should read about 13.8V and watch the multimeter while starting the car to see what it drops down to.

As for the alarm it sounds like it is struggling to get power, now alarms either have power or they don't, if it is struggling to lock the doors then this leads me back to battery power or lack of power. It wont be a bad investment if you bought a new battery because this will benefit all electrical components in you car from ecu to sound system (especially if running subwoofer/s).

Based on what you have said these are my thoughts from my experience.

agree with above, check the battery current holding ? bet its rooted

it will show 12v but wont start the car for crap, also check the grounds and positive terminals, remove them, clean with battery cleaner wire brush thingy. try it again. also voltage at the alternator doesnt mean the current is getting to the battery, just replaced one on a R31 last week, same issues, new battery ... stuffed alternator but showing 12-14 volts running

the alarm will get flaky as hell if it sees low voltage, doors will do weird things, siren on and off, etc,,,,plus the battery backup in the siren will die too if its not fixed soon...

[rawd]

awesome. thanks fellas, this is exactly what i needed to start my mission.

actually the battery is quite new (3-4 months maybe) and it still has warranty so i'll get them to check it out for me.

when i watch my volt gauge during start-up i can see it drop to 10, sometimes 8 so it definitely could be that. it never sees above 12 when the engine is off.

i will try cleaning the contacts as well cos i've never actually done that.

alarm is old and shit. siren doesn't go off ever but the pager does so that's why i've kept it.

thanks again all.

[Sloupos]

battery shouldnt drop below 10V on cranking

is it a sealed battery (maintenance free)... or has it got the cells you can top up?

you might wanna load test the battery...thats your best bet.

maybe run it past an auto elec and have a chat to them, usually they are nice enough to do a free quick battery check...

cos if its rooted, chances are you'll buy a battery off them so its in their intrests to help you out

[rawd]

battery shouldnt drop below 10V on cranking

is it a sealed battery (maintenance free)... or has it got the cells you can top up?

you might wanna load test the battery...thats your best bet.

maybe run it past an auto elec and have a chat to them, usually they are nice enough to do a free quick battery check...

cos if its rooted, chances are you'll buy a battery off them so its in their intrests to help you out

hey sloupos, yeah pretty sure i can pop off the caps and top them up. going to check out a few places tomorrow. thanks mate.

[rawd]

i just spoke to a friend that had a similar problem - only low volts when the engine was not running - and he said that it could be a starter motor issue. is this logical?

[Jmaac]

clean ground and power terminals to starter. clean battery to ground terminal

[Carbon 34]

i just spoke to a friend that had a similar problem - only low volts when the engine was not running - and he said that it could be a starter motor issue. is this logical?

at rest the battery should be 12-13 volts roughly

when you turn it over the thing will drop to 10ish if the starter is getting ready for a clean up. drawing too much current, or motor mistuned

skyline starters rarely fail, you can pull them off and clean the goop out of them, take off the end cap and shine the rotor(communicator- bronze shaft)

and clean off the laminated coils, slap it back in for another 5 years. worse case , put in new brushes. but rare

yes, new batterys do fail, my Odessy PCA 1200 failed the first week of having it, DEAD cell, wouldnt charge above 10volts

you should use some of this stuff if your battery isnt sealed, works a treat , just hard to find...lol BIG W had it I think for about 7 bucks

[rawd]

quick update - cleaned and tightened all ground contacts i could find around the car

battery is now sitting between 12-13v on standstill which hasn't happened since i've owned the car

starter motor still doesn't turn over first time/every time, but it's definitely doesn't f**k up as much.

thanks again for your help folks. saved me a lot of money i don't have.

[skygo2xs]

I have a quiet chirp from my alarm siren every time I turn the car ignition on, the siren also has the same noise when I select the silent arm/disarm option from the remote. I thought this was caused by a voltage drop, I have heard this on other cars but installers advise some cars do this and some dont, unknown why? The alarm and car dont miss a beat so not a big problem but if there is a way to fix I would like to do, any ideas appreciated....

[MUZZA450]

my s15 did that chirp after changing to an oddessy, i think you have to get the alarm key and turn it off for a while and then switch it back on.

[MUZZA450]

Another thing we did was to switch the ignition on and off quite a few times.

[skygo2xs]

thanks for the input muzza, I will have a play and see how I go. My autowatch siren doesnt have a key but Its not a big prob anyway, ill try the ignition on/off a few times and see if it does everytime though.