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Voltage Dropping/lights Dim

lench

By lench,
in Car Audio & Electrical

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lench Contributor

lench

Posted
Posted

Hi all

Just after some advice on something thats been an intermittant problem on my 34 GTT

out of nowhere (meaning i havnt touched anything) the power seems to drop when the brakes are applied, or even more obvious when the indicators are used.

in some cases im just sitting at the lights and everything goes dead

i know theres a short somewhere.. but where do i begin?

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lench Contributor

lench

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just did then. the car has been sitting still overnight so nothing could have shifted around (loose wiring) and it seemed fine when it came to test it.

the voltage when started was at 14.5v

only thing i can think of is when it happens again, pull over and give the alt a whack

Carbon 34 Grand Master

Carbon 34

Posted
Posted

Hi all

Just after some advice on something thats been an intermittant problem on my 34 GTT

out of nowhere (meaning i havnt touched anything) the power seems to drop when the brakes are applied, or even more obvious when the indicators are used.

in some cases im just sitting at the lights and everything goes dead

i know theres a short somewhere.. but where do i begin?

if its showing 14.4 running and stays that high, your battery is farked most likely , the current holding on the battery is gone.( interenal corrsion of the plates ) your battery might say 12v off, but when you crank it it's dead, NO AMPS (Current )

or corrsion on the terminals ?

loose bolts at the terminals?

if you still have one of those little ass battery from japan , bin it and buy a real one . DO NOT WHACK YOUR ALTERNATOR, it could only just damage it !!!! the old school hitting the starter fix doesn't work on it

you can spray it out with electronics cleaner IF its oiled up like hell, but beware , some cleaners can melt plastic /paint or ruin the alternator is used wrong or while running.

ground your battery with an additional 4ga cable to the bracket bolts holding the alternator and zip tie the wires to keep them from hitting anything, your car will thank you and charging will be much better.

power electrons goes from negative to positive, not the otherway around like common thinking sugguests.

the grounds for 90% of everything in the rear of the GTT are behind the rear seat back on both sides connected in a star fashion. doubt its a ground unless at the battery or something new installed wrong ?

t_revz Grand Master

t_revz

Posted
Posted

if its showing 14.4 running and stays that high, your battery is farked most likely , the current holding on the battery is gone.( interenal corrsion of the plates ) your battery might say 12v off, but when you crank it it's dead, NO AMPS (Current )

or corrsion on the terminals ?

loose bolts at the terminals?

if you still have one of those little ass battery from japan , bin it and buy a real one . DO NOT WHACK YOUR ALTERNATOR, it could only just damage it !!!! the old school hitting the starter fix doesn't work on it

you can spray it out with electronics cleaner IF its oiled up like hell, but beware , some cleaners can melt plastic /paint or ruin the alternator is used wrong or while running.

ground your battery with an additional 4ga cable to the bracket bolts holding the alternator and zip tie the wires to keep them from hitting anything, your car will thank you and charging will be much better.

power electrons goes from negative to positive, not the otherway around like common thinking sugguests.

the grounds for 90% of everything in the rear of the GTT are behind the rear seat back on both sides connected in a star fashion. doubt its a ground unless at the battery or something new installed wrong ?

agree with most but not this bit, if the engine starts ok and the problem is only intermittent i wouldnt think battery. the alterator should be able to supply those sorts of power levels without voltage dips due to indicators or lights even if the battery was stuffed. i would be turning a/c fan on max, all lights on etc then check the voltage at battery and alternator. should be 13.5- 14.4ish and less than 0.5v difference. and yes do NOT whack the alternator.

Chris Rogers Grand Master

Chris Rogers

Posted
Posted

a farked battery will do that. doesn't matter what the charge voltage is. if it has a collapsed cell (IE short) then it will take an alternator with it.

don't belt the alternator...

Carbon 34 Grand Master

Carbon 34

Posted
Posted

yes my money is on dead cell or weak one,

and or corrosion on the terminals, loose bolts holding clamps.

voltage regulators fry when the cell shorts, or jump starts gone wrong.

they can go the other way too, and overvoltage the car as well, which kills the ecu, battery, fuseable links, relays, etc. and other lovely items. high rpm tends to do that one, my bridgeport RX7 killed off many alternators some lasted 1 rev to redline before death . just a good thing it was a weber not fuel injected car.

t_revz Grand Master

t_revz

Posted
Posted

i still stick by my comment, not saying your wrong about the battery as wierd things happen and we are only diagnosing over the interwebz but i think if there isnt any shortage of power starting the car, then i would imagine indicators should be piece of cake. dead cell batteries usually have a standby voltage around 10v so will start but sound sad.

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