My lights dim at idle on my valver...any ideas?

[AmirClio]

i was sat at the lights on the way home from work and was jus faffing about listening to my exhaust. i was looking at my rev counter at the time and as the revs drop and it sits idle the lights dim slightly inside and out????????
and when i rev it again they brighten up agen!

bad earth??? alternator????

any ideas folks??

cheers
Amir

 

[Da]

more than likely the alternator but I would firstly check all earthing connections along with battery terminals. Grease them up and if possible test the battery to see what voltage it is giving out.

 

[AcID ZeR0]

Do you have a sound system on or the blowers?

 

[AmirClio]

Do you have a sound system on or the blowers?

yeh blowers were on, and you could here them going slower wen the revs dropped. sounds were off tho
but if it was the alternator, wouldnt the battery warning light come up on the dash?

 

[Da]

the warning light would only come on if the alternator failed totally, the dim in your lights just shows that something (alt or battery) is not working 100% or as i said a connection is a bit dodgy.

 

[AmirClio]

the warning light would only come on if the alternator failed totally, the dim in your lights just shows that something (alt or battery) is not working 100% or as i said a connection is a bit dodgy.

rite, ok well i'll check all the earths do mean like all the earths on the loom?? or just one coming off the battery?

in the mean time if anybody else has an ideas just post!!!

cheers Daz!!

 

[bmh.01]

Would of though it was either the battery or alternator. If you've got another battery to test then i'd try that too.

 

[Da]

check the main ones, like from -ve of batt to chassis and the main earth to alternator etc.

 

[AmirClio]

all sorted!!!!
i swaped the engine coolant at the weekend, and hadnt put enuff back in!!! its amazing how much goes in there! lol well filled the expansion tank up let it run through and it was fine. lights stay bright now! strange resolution to it but it did the trick! hope i havent done any damage to my engine :S

thanks for ur input anyway!

Amir

 

[BRUN]

what voltage are you getting across the battery at idle, and then again with your lights and blowers on

 

[Daz]

Engine coolant?
Dimming lights?

:rasp:

 

[AmirClio]

Engine coolant?
Dimming lights?

:rasp:

thats right, strange as it sounds thats wot resolved the problem! ive never known anything like it but it worked!

very odd, i noticed it on the way home, then i went out to check the earths all seemed ok, confused i was jus checking everything else and the coolant bottle was more or less empty. filled it up ran it through with the heaters on full wack and then car idled very slightly higher and stopeed the lights from dimming!

ch-ching!
strange tho

 

[AmirClio]

what voltage are you getting across the battery at idle, and then again with your lights and blowers on

rite just checked it out and its way overcharging! its running at 16volts idle and 15volts with lights and blowers on!
gonna get it checked out 2day, asked one of techies at work he said could be an alternator fault! grrrr god dam cars!!! lol

 

[Scoop25]

15 volts isn't that high..although it's a 12v battery, it's not uncommon for under power to exceed 14-15v. Think my 16v sits about 15.5v under load. The lights dimming is again not uncommon, means the battery is a little low, but if they brighten up when revved slightly higher, means the alternator is doing it's job.. The fact that when you added coolent the reves increased (albeit v strange), this is what resolve the problem, not the collent directly. So battery is prob on it's way out.

 

[AmirClio]

Right cheers for that!

Its doing it again!!!!! and its nothing to do with the engine coolant this time! Battery? Alternator? one of the techies here at work said does it smell eggy after its been driven...which it does slighty. He then said this cood be the battery over charging??

any ideas please!!!
Amir

 

[bunzee]

I thought eggy smells were caused by catalytic convertors - if they smell eggy it's normal?

 

[danny1]

Its Normal happens on most cars,

When you try to draw current from the battery by using more electricity ie blowers, rear screen demister, lights etc

The alternator tries to create more charge on the battery which makes the alternator harder to turn at idle, when you rev the car it increases the revs and makes the alternator turn faster creating more charge and making the lights go brighter again.

It wont hurt but if you want to get rid of it get a high amp battery which can store more charge and not make the alternator work as hard to charge the battery when it is fully charged.

hope this helps

 

[BRUN]

yup, instead of the small 063 type battery you probably have, remove the rubber block on the battery tray and fit the larger and more powerful 065 type, thats whats on mine

instead of being about 400CCA, mines 565CCA some are 600CCA, with a better Ah energy reserve aswell

 

[AmirClio]

Its Normal happens on most cars,

When you try to draw current from the battery by using more electricity ie blowers, rear screen demister, lights etc

The alternator tries to create more charge on the battery which makes the alternator harder to turn at idle, when you rev the car it increases the revs and makes the alternator turn faster creating more charge and making the lights go brighter again.

It wont hurt but if you want to get rid of it get a high amp battery which can store more charge and not make the alternator work as hard to charge the battery when it is fully charged.

hope this helps

its not the standard battery, its a bigger battery off a van or something cus the fella who had it before me was running some serious ICE. this is y i think that battery could be the battery!
i Havent got a Cat so it aint that lol
Amir

 

[AmirClio]

ok well after a good faff ive found the problem. the lights only dim when there are main beam (second turn of the stalk for driving at night) when these are are the dash lights dim and the blowers slows. then wen i turn them off the dask lights brighten up and the blowers piks up agian. and still they brighten up as the revs go above idle.
im thinking its just a bad earth thats tapped off the lights??

Any ideas guys

 

[midge]

as other people have said mate thats normal on alot of cars, my valver has done this since ive had it, 4 months.