View Full Version : 88 5.0 Electrical / Alternator Problem
Rolling along in my 88 5.0 last night and the battery started to discharge. The battery was completely dead by the time I got home (within a half hour).
Obviously my alternator was not charging the battery. I left a trickle charger on the battery over-night and recaharged the battery for testing the next day.
With the battery fully charged and the engine off my volt meter reads 12.7 volts at the battery. With the engine running (no other electrical load). At 1500 rpm the volt meter reads 14.5. At 2000 rpm with headlights on and A/C running on high the volt meter reads 14.4.
So everything is telling me the Alternator is working fine. Why would it stop charging last night while driving and now be working? I did notice while driving that the battery indicator flickered. Could this point to a short in a circuit? I've checked the fuse link between the Alternator and the Battery. I suppose it could be a faulty starter relay. Battery cables look good. Belt tension is fine. Maybe the 5.0 fairy fixed it while I slept.
Jacostang
11-01-09, 09:13 PM
I believe you need to take the battery in and test it first.. It could have short inside it..
If its an Optima battery Id replace it. Optima is not the battery it used to be since selling out to Interstate. I was havin tons of electrical issues with my Firebird, because my Optima was nearly new I never considered it to be the problem, so my stereo guy says Optima batteries are not good as they used to be. So he trades out my optima with a Delco battery to see if it fixed the issue. Sure enough not one problem since.
Im sure others will still swear by Optima, I used to as well. But after the issues I went thru Im no longer a believer. :laughing:
let the car warm up for a while, then test the alternator, it may be overheating
Mr. Austin
11-01-09, 10:52 PM
I actually just has that issue with my 69 mustang with a 302. battery dies on me while idling at a sonic. I took my car to checkers (right next door) and they tested with my amps and extra fog lights and electric fan on and the alternator was perfect. Did the whole trickle charged tried again and found out what it was was my ground to the battery. It was touching like it should but unless someone did it i must have accidentally cut a small piece of the rubber around the wire off. I tightened the wire so it connected better and wrapped the inch whole in the vinyl tape. it held a better charge but played with my wires and tightened everything down and she has been fine since. All in all check you wires before you go pulling hair out. you will never know if they are all connecting correctly even if they look to be.
Thanks for the quick replys ... I believe I have an Interstate battery (green), I've been wanting to replace it with a Motorcraft anyway, now is as good a time as any. I'll give the wires another good look and also check the overheating possibility. Thanks guys!
Changed the battery. The problem has not returned ... yet.
Jacostang
11-16-09, 11:11 PM
Good News!!
Mr. Austin
11-17-09, 12:39 AM
great!
The Problem is back ... Driving tonight the volt gauge was bouncing around from 14 to 12 to 10 and then back to 14. So I pulled the alternator out and removed the voltage regulator. The brushes in the regulator are certainly worn down. I'm sure I could replace the regulator and not have any problems for a long time. BUT, with the alternator out from under the hood I figure I will go ahead and have the whole thing rebuilt. Anyone know a good place to have it rebuilt?
HanksGT
12-02-09, 12:56 AM
I have used Phoenix Genrator Exchange with good results.
The Problem is back ... Driving tonight the volt gauge was bouncing around from 14 to 12 to 10 and then back to 14. So I pulled the alternator out and removed the voltage regulator. The brushes in the regulator are certainly worn down. I'm sure I could replace the regulator and not have any problems for a long time. BUT, with the alternator out from under the hood I figure I will go ahead and have the whole thing rebuilt. Anyone know a good place to have it rebuilt?
scottman70
12-04-09, 11:05 PM
Hey there if that there Mustang of yours is annoying you I would be happy to give you $1500 cash for it today! :biglaugh:
Replaced the alternator, but problem is back ... Headlights were flashing on and off last night, voltage meter was randomly dropping. Frustrating.
Found this link... there was actually a Ford service bulletin about the headlight / foglamp flashing problem. http://www.corral.net/tech/maintenance/foglights.html
Jacostang
12-27-09, 06:58 PM
If you are running both the headlights and the "GT" lights and do not have it retrofitted it will throw the relay alot, it over loads it. The retro fix is easy and I have done it on both of my Foxes. Once fitted with the extra relay you can run your GT lights with your brights on also, its very nice and you wont have that problem anymore, I thought it was mainly a charging issue..
Yes, it is a charging issue... and a retrofit problem on top of that. Pulled the brand new alternator out and had Autozone bench test it ... it failed all tests. Drove to Sanderson and replaced it with another. Installed the replacement and will have Power Ford run an electrical diagnostic in the morning.
Jacostang
12-28-09, 11:14 PM
Very cool, and let me know if you want help with the retro fit. I would be glad to help you out with that.
Dave
Thanks, I definitely want to do the retrofit ... once this charging issue out of the way.
Hopefully this is the last post on this topic. Took the 5.0 to Power Ford, they traced the problem back to a short in the ignition switch... replaced the switch, problem gone!
Jacostang
01-03-10, 12:42 AM
Great! I hope...
Torchmach
01-03-10, 09:21 AM
Hopefully this is the last post on this topic. Took the 5.0 to Power Ford, they traced the problem back to a short in the ignition switch... replaced the switch, problem gone!
The Electronics are one of the three trouble causing systems in Fox Mustangs (Cooling, and manual transmissons the other two). You got to love them anyway. Good to hear your problem is resolved.
Interesting you should mention cooling. While the 5.0 was at Power they diagnosed a water pump leak.... so I spent a few evenings hunched over the front-end replacing the water pump, hoses, and thermostat. It's all buttoned up now. Took it for an extended ride last night and all looks well. Waiting for a replacement coolant tank I ordered from 50Resto... my original is cracked.
So, what should I expect to go wrong with my manual transmission (I'm at 39K miles now)?
scottman70
01-03-10, 04:19 PM
Interesting you should mention cooling. While the 5.0 was at Power they diagnosed a water pump leak.... so I spent a few evenings hunched over the front-end replacing the water pump, hoses, and thermostat. It's all buttoned up now. Took it for an extended ride last night and all looks well. Waiting for a replacement coolant tank I ordered from 50Resto... my original is cracked.
So, what should I expect to go wrong with my manual transmission (I'm at 39K miles now)?
Well if you install a set of FLowmasters that should help your transmission from failing!:biglaugh:
Dear Forum Manager ... how do we kick a user off this forum?
scottman70
01-03-10, 05:21 PM
Dear Forum Manager ... how do we kick a user off this forum?
Ha Ha your funny!:biglaugh: You know your car would sound better with some Flowmasters!!
scottman70
01-06-10, 07:57 PM
Hey, hows the starter replacement going man?:popcorn:
Do ya need any help under that 5.0? :hide1:
Let me know me and Bill can come over and get
the 5.0 rolling strong again! After all we have to drag
race our cars man!
Dear Forum Manager ... how do we kick a user off this forum?
clickity click click click
scottman70
01-06-10, 09:46 PM
clickity click click click
Actually Mr. Ford is a good friend of mine! :beerchug:
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