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Discussion Starter · #1 ·
As it was raining today I parked up under cover and thought it looked like the lights were flickering slightly. Leaving the engine running I got out to check and noticed that all the lights (Head, Tail, No. Plate, and as I had the door open, Interior) were flickering slightly, not going out completely but pulsing enough to notice.

The bulbs are of a normal type (not HID or LED) and the only upgrades are Osram Night Breakers for the dipped beam and Osram Diadems for the number plates.

Aside from the radio and the fan at 1 there were no other accessories running and the car had been running for about 40mins.

With the engine off the lights (Tail and No. Plate as the headlights go off with the engine off) stay constant.

Does this sound like normal behavior?
 

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Do they steady out with a touch of revs? The alternator may not be kicking out enough voltage at idle causing the 'flickering' or maybe an earth connection isn't good?

Maybe check what voltage the alternator is producing at idle.
 

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Discussion Starter · #3 ·
Do they steady out with a touch of revs? The alternator may not be kicking out enough voltage at idle causing the 'flickering' or maybe an earth connection isn't good?

Maybe check what voltage the alternator is producing at idle.
Haven't checked, I'll see if the interior light smooths out at all with revs tonight (for the exterior lights I'll need another pair of feet).

Googling flickering lights all seems to point to alternator/battery problems. I can understand a battery going on a 3 year old car but an alternator at such an early age low mileage (24k) surely not?

It may be unrelated, but yesterday I'd left the car running to defrost with the heated screens on and after a while I noticed the revs hunting a little (I put it down to the extra load and the engine warming up and dropping down to a regular idle). They setted down as soon as I turned off the rear heated screen.
 

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Discussion Starter · #5 ·
Perhaps, though I haven't noticed any squeals to suggest a belt, when I had a bad belt on my Skyline it squealed like a bitch (it also had a volt gauge which showed a drop to around 8.5v when slipping).
 

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Discussion Starter · #7 ·
I had a better look this evening when I finished work, here's few observations:

In the car park:

- No flicker when the lights come on when you unlock the car.

- No apparent flicker from a cold start and engine is still at high idle.

At home after a 40min commute:

- Lights flicker with engine note.

- Lights flicker more with front and rear fogs on.

- Lights flicker less (almost not at all) with just side lights on.

Sat inside:

- Interior light flickers at idle (less so with foot on clutch).

- No apparent flicker from the Interior light when holding the revs slightly higher.

I'd say it all points to not enough voltage at idle. I imagine it's probably considered normal and without spending money investigating (I don't have a volt meter unfortunately), I think it may have to go in the 'Keep an eye on it and wait for more severe symptoms' book.

The flicker its very subtle, more like momentary dips or spikes in the brightness. I tried to capture it on my phone but it's so subtle it didn't really show up (no more so that the way lights/screens tend to flicker a bit on a camera.

As I say, you don't often stand outside the car with the engine running and lights on so it could be something that more cars exhibit but no one notices. As these cars have LED driven dash lighting there's less sign of it happening inside (traditional bulb lit dashes would flicker with the lights, my Civic's dash for example would dim in time with the indicators).
 

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(I don't have a volt meter unfortunately),
Definitely go and get yourself one, only cost a few quid for a basic one and they are really useful.

You can even get cigarette socket plug in ones so you can see what's happening while you're driving. You may only need them now and again but great to rule out issues with electrical stuff.
 

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@Bumgrape finally took some readings today as follows:

Battery after unlocking - 12.2V
Battery after being left for 10-15 mins - 12.55V (I'm guessing the stereo and other components draw some voltage when unlocked and go off after a while?)
After a 40min drive, with lights on and blower at 1 - 14.97-14.99V (lights off - 14.90-14.92V)

So I would safely say it's not under powering at idle, if anything it seems to be running a tad high? (Highest I've seen in cars before was 14.5V, and my Civic used to run happily at 14.3V).

Can anyone advise further?
 

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I assume the first voltage (after unlocking) is engine off? but what is the 12.55?? is that engine off or on

14+ I would certainly say is the alternator charging the battery.... and indicates IMO the charge system is working fine.
 

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Battery after unlocking - 12.2V
Battery after being left for 10-15 mins - 12.55V (I'm guessing the stereo and other components draw some voltage when unlocked and go off after a while?)
After a 40min drive, with lights on and blower at 1 - 14.97-14.99V (lights off - 14.90-14.92V)

So I would safely say it's not under powering at idle, if anything it seems to be running a tad high?
All looks fine as you say.

Yeah on unlocking the car will fire up some systems and draw some amps, so it's usual for the voltage to be a tad lower. When running mine was just below 15V too, I also thought this was a bit high but it seems ST's have a high output from the alternator so is normal.

If that values at tickover then you definitely dont have a problem with the alternator/current, so hard to know what the issue is. Seems odd if the voltage is not an issue that they would flicker at idle only though. I was wondering if it could be a dodgy earth somewhere, but again I doubt it would show just at tickover if the voltages are good and it's fine at normal revs.

I'm afraid I've run out of ideas fella.
 

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As @Bumgrape says voltages look fine and difficult to se the problem, have you checked side by side against other cars incase its just your eyes being hypersensitive? The only possible other thing I can think of is that the car (assuming it has one in these modern "smart charge" microprocessor auto cut-off when not required) regulator is not working 100%. I say this because the alternator is obviously working well and producing more than enough power but (IMO) 14.9v is a tad high (I would expect 14.2 - 14.6V) though I am not an auto electrician and do not know for certain what ST's definitively run at just general battery info from years playing with 12V systems. May be worth a visit to a auto electrician or at worst case ford!!

Actually just seen this which may help on a ford site:

http://www.fordownersclub.com/forums/topic/69546-alternator-voltage/

The last bit talks about disconnecting a wire to test the smart charge me thinks...
 

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I was convinced my ST was doing this a few weeks back after I had piggybacked a dash cam from a permanent live fuse to a power magic pro but haven't noticed lately, usually when I was locking up at work with everything on, heated seats, dash cams, headlights radio etc, just an idea!
 

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Check the regulator on the alternator hasn't gone - this happened on my mate's Sierra. You'll need assistance to check this.

Put the volt meter across the battery terminals & get the base value (should be about the 12.2 you've identified). Fire the engine up & check it rises to your 14 or so. Put the dips on to give it a bit of load.

Get a mate to gently increase the revs to 2000, then 3000, then finally 4000rpm. The volt meter should hold at your 14v figure, plus or minus about 0.2 or so volts.

On that Sierra, it got to 16 volts & 2500rpm & I told him to shut it off. It was also obvious that the dips were getting significantly brighter as the revs increased.

If there's more than a few tenths of a volt of movement when you do this test then the alternator regulator needs replaced. An auto electrician should be able to do this without replacing the alternator, though worst case you might need an exchange alternator.
 

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Didn't see any reference to checking if the alternator was overcharging the battery.
Do they steady out with a touch of revs? The alternator may not be kicking out enough voltage at idle causing the 'flickering' or maybe an earth connection isn't good?

Maybe check what voltage the alternator is producing at idle.
Thread goes on to show voltage is just under 15V with engine running and load on, so alternator is fine.

Anyway, I did put a wink at the end just to show it was tongue in cheek and a bit of fun :)
 

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All looks fine as you say.

Yeah on unlocking the car will fire up some systems and draw some amps, so it's usual for the voltage to be a tad lower. When running mine was just below 15V too, I also thought this was a bit high but it seems ST's have a high output from the alternator so is normal.

If that values at tickover then you definitely dont have a problem with the alternator/current, so hard to know what the issue is. Seems odd if the voltage is not an issue that they would flicker at idle only though. I was wondering if it could be a dodgy earth somewhere, but again I doubt it would show just at tickover if the voltages are good and it's fine at normal revs.

I'm afraid I've run out of ideas fella.
Yeah its a strange one. The fact it seems to dip with the engine note/burble, it's almost like something on the engine itself is drawing too much load. I know on diesels its common for the lights to dip in cold weather as the glow plugs come on alot more, but on a petrol aside from the fan and the sparkplugs there can't be alot of extra electrical load?!
As @Bumgrape says voltages look fine and difficult to se the problem, have you checked side by side against other cars incase its just your eyes being hypersensitive? The only possible other thing I can think of is that the car (assuming it has one in these modern "smart charge" microprocessor auto cut-off when not required) regulator is not working 100%. I say this because the alternator is obviously working well and producing more than enough power but (IMO) 14.9v is a tad high (I would expect 14.2 - 14.6V) though I am not an auto electrician and do not know for certain what ST's definitively run at just general battery info from years playing with 12V systems. May be worth a visit to a auto electrician or at worst case ford!!

Actually just seen this which may help on a ford site:

http://www.fordownersclub.com/forums/topic/69546-alternator-voltage/

The last bit talks about disconnecting a wire to test the smart charge me thinks...
On most cars 14.3-14.6 seems the ideal range but I've seen numerous reports that Ford's with the smart charge it's 14.6-14.9 with peaks of 15.2 if the battery's really dead.
Check the regulator on the alternator hasn't gone - this happened on my mate's Sierra. You'll need assistance to check this.

Put the volt meter across the battery terminals & get the base value (should be about the 12.2 you've identified). Fire the engine up & check it rises to your 14 or so. Put the dips on to give it a bit of load.
Get a mate to gently increase the revs to 2000, then 3000, then finally 4000rpm. The volt meter should hold at your 14v figure, plus or minus about 0.2 or so volts.
On that Sierra, it got to 16 volts & 2500rpm & I told him to shut it off. It was also obvious that the dips were getting significantly brighter as the revs increased.

If there's more than a few tenths of a volt of movement when you do this test then the alternator regulator needs replaced. An auto electrician should be able to do this without replacing the alternator, though worst case you might need an exchange alternator.
I know it's not 100% accurate, but I ran my car with the dash in test mode which shows battery voltage and whilst driving it seemed to run at 14.5-14.9V at various loads. In the short drive I didn't anything higher or lower.
 
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