Faulty Alternator(overcharging)

[MarcKemp-sq]

On GMs I've had two alternator issues. Bad bearings and diode triads but I've heard of the occasional regulator issues on the modern type. On Ford I've only ever had one issue. But I've known of two. Voltage regulator and the occasional diode issues. I just remembered I did replace one alternator on a Lincoln for a bad bearing but just one out of umpteen. I'm not really a mechanic but it's always paid me to figure things out even if I had to watch a video a few times first. Two days ago I was in Joplin for a doc appt and I just kinda thought the car wasn't running just right, down on power, etc. So I plugged in with my live data scanner and looked it over. The LTFT caught my attention because it's usually running around 0.0-1-2 % either way. So it was adding fuel. So I stopped and looked at the grams per second on the MAF and that was ok. The IAT was slightly low by a couple deg and that indicated to me why it could be running lean. I thought since the car was warmed up there ought to be some under hood heat added to the ambient. But it kept showing a steady couple deg below the ambient and I knew that wasn't right. I looked at the fuel pressure (08 Grand Marquis has a fuel pressure sensor in the rail so that's very handy to know your psi). It was fine. Perfect. I looked at the O2 data and they were doing their thing. The MAP and BARO data checked out. 0-1000 feet should be about 29.9 in but I'm over a thousand feet so 29 is typical. You subtract the MAP from the Baro and that'll tell you the vacuum in the intake. Then I found something that I was like, well that shouldn't be that high since the car is warmed up and the battery voltage is fine. The alternator was overcharging and that can be a bad thing because it'll fry the sensors and then the computer and wiring too if it gets ignored too long. It was slightly overcharging but too much to ignore. So I ordered a new alternator and on a hunch the MAF because in those years the IAT is also part of it and it's the weakest link. Hitachi was the supplier for Motorcraft, I know they were. They also supplied a lot of GM vehicles. That's $50 delivered. The Motorcraft, $140 delivered. Same thing. The Hitachi will have the Ford numbers scratched off and their numbers over it. Motorcraft doesn't make anything. AC Delco doesn't make much either. They supply a spec and manufacturers bid on it. I don't buy Motorcraft plugs. NGK makes them. Sometimes you can see NGK on a Motorcraft plug. Sometimes you can see it on an AC Delco plug. Anyway Ford doesn't sell a new alternator so I ordered one from who supplies a lot of them for Ford and GM...Remy. Remy supplies for Delco. My box said, Delco but I can tell it's a Remy. They got split post bankruptcy. It's perfect now. I've got some spinal scoliosis and a sciatica nerve that bothers me and.. just several other compressed nerves in my lower back but I still do what I can because I don't have endless money. I could borrow it, but I hate paying interest. My Dad was my mechanic. I can mess around with putting something back together and take 3 times the time it takes a mechanic but he couldn't figure out feedback systems and I have that part figured out...or figure it out on a need basis. So now the alternator isn't overcharging and it's not frying sensors and it's back to running great. I knew something wasn't right a week ago because it was a little harder to start on really cold mornings and a bad IAT sensor usually makes them run slightly lean by default. I almost replaced the MAF thinking it was that because that'll make them a little harder to start too. But I kept seeing good grams per second. I just didn't look far enough.

[Daniel-gnuo]

Did you fix the problem? Was it the alternator regulator or the battery

[williamd]

If you can buy the voltage regulator just replace it.

[soekasnosolichin]

Maximalnya hnya 14, 8 volt. Klonlbih dr itu. Overcharging dn aki akan rusak

[tylergeorge]

So the alternator needs to be replaced?