Dim lights at idle on 68 - Vintage Mustang Forums
Vintage Mustang Forum
HomeForumGalleryClassifiedsAbout UsAdvertiseContact Us
» Auto Insurance
» Featured Product
Go Back   Vintage Mustang Forums > General Discussion > Vintage Mustang Forum
Vintage-Mustang.com is the premier Ford Mustang Forum on the internet. Registered Users do not see the above ads.
Reply
 
Thread Tools
Old 05-23-2003, 10:22 PM   #1 (permalink)
Senior Member
 
Cruzer's Avatar
 
Join Date: Mar 2001
Location: Lancaster, SC
Posts: 4,082
Default

With the headlights on & idling the headlights & dash lights are dim. As soon as I press the gas pedal they get bright. Is this the altenator or what?
Thanks in advance.
Cruzer is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 05-23-2003, 10:27 PM   #2 (permalink)
Senior Member
 
Join Date: Mar 2001
Location: St. Louis, Mo.
Posts: 786
Default

That's probably normal for a stock alternator. Their output is not what todays high output alternators are. Just make sure your belt is tight, but it probably, as said, is normal. I simply means that at idle speed, the alternator output is lower than the battery draw, thus the lights dim until the engine/alternator is sped up.
Tom
I wouldn't worry about it.

Tom
__________________
http://www.lagerdc.com/assets/images..._MVC-462S1.jpg

www.lagerdc.com/html/mustang.html (Click left for more pictures!)
[red]70 Coupe, 302, 2v. Purchased in May 99, paint & body work completed Sep 2001.[/red]
70_Coupe is offline   Reply With Quote Quick reply to this message
Old 05-23-2003, 11:10 PM   #3 (permalink)
Senior Member
 
Join Date: Mar 2003
Location: Texas
Posts: 282
Default

Yeah, just idle 'er up to 1,200rpm, problem solved, LOL.
You might try cleaning all the connectors sending volts to those lights though, might knock out enough resistance to make a difference.

__________________
'66 Coupe EFI T5, power Granada swap, homemade awesome power rack & pinion steering, great cruiser.
[color:"red"]Don't steal, the government hates competition!
[color:"blue"]Have you driven a Yugo lately?[/color]
http://pic13.picturetrail.com/VOL480...8/56907606.jpg
HughStonne is offline   Reply With Quote Quick reply to this message
Old 05-23-2003, 11:22 PM   #4 (permalink)
Senior Member
 
Join Date: May 2001
Posts: 6,911
Default

It's possible over time stop and go driving in conjunction with an old charging system could leave the battery a bit flat.....maybe you could trickle charge it for a while before driving it at night and see if it acts the same?
__________________
Ported vacuum IS manifold vacuum ANYTIME the throttle is open on a holley.
sharkmouth is offline   Reply With Quote Quick reply to this message
Old 05-24-2003, 12:52 AM   #5 (permalink)
Senior Member
 
Join Date: Nov 2002
Location: boise idaho
Posts: 466
Default

its normal if you ask me, mine has always done it since the day i got it and others do the same.
__________________
351w with 10.3 compression, .520 lift comp cam, edel rpm performer manifold, world 200 heads, 750 edel carb, block was hot tanked, bored .03 over, crank turned, balanced, put to the ground by a C4 and 3.55 8"with powertrax and expelled by all hooker headers
best run: 13.10 at 104.4 mph

[image]/image]
stang6992 is offline   Reply With Quote Quick reply to this message
Old 05-24-2003, 01:09 AM   #6 (permalink)
Senior Member
 
Pathfinder's Avatar
 
Join Date: Mar 2003
Location: Ontario, Canada
Posts: 1,614
Default

I changed my regulator for an electronic style and it helped a lot with the dimming of lights at idle.

Dave
Pathfinder is offline   Reply With Quote Quick reply to this message
Old 05-24-2003, 01:24 AM   #7 (permalink)
Guest
 
Posts: n/a
Default

The 68 alternators were designed to put out 40 amps. The 87-on up alternators put out anywhere from 75-130 depending of the year. Here is some info on how you might be able to get a more powerful alternator put on your 68.
http://www.ronmorrisperformance.com/...ess/altern.htm
  Reply With Quote Quick reply to this message
Old 05-24-2003, 01:36 AM   #8 (permalink)
Senior Member
 
Join Date: Mar 2003
Location: Monticello, New York
Posts: 1,707
Default

sounds normal upgrade the alternator
theokponycorrall is offline   Reply With Quote Quick reply to this message
Old 05-24-2003, 01:44 AM   #9 (permalink)
Guest
 
Posts: n/a
Default

wore out brushes
  Reply With Quote Quick reply to this message
Old 05-24-2003, 02:05 AM   #10 (permalink)
Senior Member
 
SacBill's Avatar
 
Join Date: Jul 2001
Location: Sack-a-tomatoes
Posts: 4,072
Send a message via AIM to SacBill
Default

Check this out. ::
SacBill is offline   Reply With Quote Quick reply to this message
Old 05-24-2003, 06:17 AM   #11 (permalink)
Guest
 
Posts: n/a
Default

Quote:
wore out brushes
Brushes Alteranators don't use brushes. Just generators. Jeez!
  Reply With Quote Quick reply to this message
Old 05-24-2003, 08:38 AM   #12 (permalink)
Senior Member
 
Join Date: Mar 2001
Location: Buffalo, NY
Posts: 3,628
Default

if you have a voltmeter measure voltage at battery terminals with engine running - should be 13.5 to 14.5 Vs. your fan belt might be loose or if you have special racing type alt it may give you that condition. do not overtighten alt belt or you will possibly damage alt or water pump bearings. PM me if questions.
__________________
'68 6-cyl coupe
Pertronix
Canadian Mustang "Big Kit"
Pony Carb
BillScott is offline   Reply With Quote Quick reply to this message
Old 05-24-2003, 08:42 AM   #13 (permalink)
Senior Member
 
Join Date: Jun 2002
Location: Eastern PA
Posts: 114
Default

That was a great site Sacbill led me to.
My '67's dash lights would dim then go out completely at idle. Then the headlights would dim, they would flicker at high beam, and the tail lights would dim.
I fixed both by new 100 amp alternator and new Optima battery. Now I can listen to the radio at red lights without the car running out of juice and stopping
I am going to check my voltage at the back of the lights to see If i need that relay from that red light as soon as I get my car back from the shop.
Gordy
__________________
Gordy
1967 'vert, 289 4v, t5 conversion, 3.55 auburn rear
gordy is offline   Reply With Quote Quick reply to this message
Old 05-24-2003, 11:55 AM   #14 (permalink)
Senior Member
 
Join Date: Mar 2003
Location: Texas
Posts: 282
Default

Quote:
Brushes Alteranators don't use brushes. Just generators. Jeez!
REALLY? Then how do you think the (rotating)field windings get engergized Take an alt. apart, yes you will find "brushes". They last a lot longer in an alt. because they only have to carry the light current to magnatize the field windings, instead of carrying the heavy output current as in a generator. So most people probably never have had to service them.
__________________
'66 Coupe EFI T5, power Granada swap, homemade awesome power rack & pinion steering, great cruiser.
[color:"red"]Don't steal, the government hates competition!
[color:"blue"]Have you driven a Yugo lately?[/color]
http://pic13.picturetrail.com/VOL480...8/56907606.jpg
HughStonne is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Vintage Mustang Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are Off


Powered by vBadvanced CMPS v3.2.2

All times are GMT -4. The time now is 01:38 AM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.3.2 ©2009, Crawlability, Inc.