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gdsqdcr
12-09-2011, 10:04 PM
I am running a Zack tune. UDP's were put on a out 8000 miles ago and I had. I issues with dimming lights. The original battery is still in the car.

Over the last few days, I have noticed at idle, lights dim, voltage gauge at 10.5. Once the revs are up, no dimming, and the Voltage gauge reads 13.


Thoughts?
Alternator
Battery
Tune ... Don't think so cause the issue just started.
fastblackmerc
12-10-2011, 05:21 AM
I am running a Zack tune. UDP's were put on a out 8000 miles ago and I had. I issues with dimming lights. The original battery is still in the car.

Over the last few days, I have noticed at idle, lights dim, voltage gauge at 10.5. Once the revs are up, no dimming, and the Voltage gauge reads 13.


Thoughts?
Alternator
Battery
Tune ... Don't think so cause the issue just started.

Does the tune compensate for the UDP's by increasing the idle RPM?

How old is the battery?
RF Overlord
12-10-2011, 07:40 AM
With U/D pulleys, you need to bump the idle in drive by 100-200 RPM. Your battery *could* be getting old, too, but raising the idle in drive will clear the dimming.
gdsqdcr
12-10-2011, 08:31 AM
Battery is original.

I read about bumping the tune up, but did not see any issues until earlier this week. That was why I was not convinced the tune was the problem.

How do I bump the idle up?
Krytin
12-10-2011, 08:36 AM
Original battery on an '03? Shoot the lock of your wallet and get a new one!! LOL
Seriously - a battery w/bad cell could fry the alternator and put a hurt on your starter!
ctrlraven
12-10-2011, 08:40 AM
Hook up your tuner to the car, follow through like you are going to upload a tune but where it asks about modifying or changing parameters you want to say yes, scroll down to where you see Idle Rpm or Drive Idle Rpm, it should be at 725-775, bump it up 800-850.

When the car is in drive gear and at rest the alternator is at it's lowest charging point. Mine was at 750 but if I turned on the rear defrost with the headlights on I went from 14.3 to 13.0, bumped my idle rpm up to 800 and all seems fine now.

You should probably go ahead and replace your battery as well before it gives out on you one day at bad time.
4drcbra
12-10-2011, 11:15 AM
Bump ur idle up about 200 rpm
SpartaPerformance
12-10-2011, 11:39 AM
I agree with Krytin, you're reading too much into this 99% your 8 year old battery is the issue.
Vortech347
12-16-2011, 03:46 PM
Your batt will take a **** soon. Time to get a new Motorcraft one and bump up your drive and idle RPMS.