Diegopy94

92 f250, 351 zf5 4x4

This started a few days ago and has gotten really bad.. At first I thought it was a parasitic battery drain cause the battery was always dead when I went to start it. Driving home from work after a boost today I realized the volt gauge on the dash was far left and my battery was not charging. Drove around a little further hoping it would charge but it didn't. Then on my way back to my house it started wanting to stall every time I shifted, all electronics would die but it would keep driving. When I opened the door to get out (still running) it nearly stalled parked, same thing as when shifting all interior electronics die but it was simply opening the door. Plugged it into a drip charger.

it seems really obvious to be the alt but its got a new one a year ago, and a new battery. I'm gonna go test the alt after dinner.

wondering if its something that's not the alt cause I would rather believe the new one lasted longer than this.
thx

Steve83

"New" doesn't tell us much about these parts. Where did they come from? What brand & PN is each one? Who installed them? Why (for each)? Pics would help. Click this & read the caption:


(phone app link)

For any charging issues, always start with the BATTERY TERMINALS. Click this & read all the captions:


(phone app link)

Then check the OTHER end of each heavy cable:


(phone app link)

And even a good, new alternator can't work if its mounting surfaces are dirty:


(phone app link)


(phone app link)

Diegopy94

Thanks for those links. The alt is a motomaster, was all I could afford at the time. The batt is an optima red top. Connections to and from the batt and alt are all clean. Since I left it on the charger it seems the Batt hasn't been taking a charge, charger says its at 25% and voltmeter read 10.1V. Didn't try turning it on when I was checking the batt, gonna give it a bit longer and look again(didn't test alt).
belt had tension.
found in my fuse box the diode and a 5amp fuse didn't have continuity, doing some research into those. Don't know anything about the diode or if its even supposed to have continuity but I'm doing a quick search now.

Diegopy94

Forgot to mention I connected my ford obd1 reader to it when I was checking battery and fuses. No current codes or stored codes with key on engine off test. Didn't test it with engine on cause I figured I would give the batt a little longer to charge.

research on the fuse and diode I don't think those are my problems. Don't think my meter is strong enough to test diode (hence no continuity) but they both appear to be none related to the problem.

Diegopy94

Truck did not start as battery is not taking the charge. Didn't have anything to boost with so I will continue tomorrow.

Diegopy94

Boosted it to test alt. Right after boost the voltage reading from the batt terminals was 14.15V, under load test it was 13.9V. Ran fine wile parked but the dash volt meter stayed near the left and seldom moved. Tried to test wires off the voltage regulator but the backing of the connector didn't allow for my multimeter probs to go deep enough to get a reading.

after turning it off there was a hum noise from 2 relay looking things near the coil.
then through the gauge on my drip charger I watched the battery drop to dead. With the multi meter on the batt with the drip charger connected it still reads 12.5V.

It sounds like the voltage regulator but I couldn't get a reading off any of the wires on the back of the connector. Or could it have something to do with these relays that made the hum? (Left of coil below the hoses that used to pump air into the exhaust)

Diegopy94

What other ways are there to test the regulator?

Steve83

That's NOT a good one. I recommend MotorCraft TestedToughMax, Interstate MTP, or Sears DieHard Gold.WHICH voltmeter? The dash; the one on the charger; or some handheld one (brand/model)?Diodes are open (off, non-continuous) with one polarity, and nearly closed (short, continuous) with the opposite polarity. Reverse the meter probes on the diode's terminals.Scanners are UNreliable on these old EECs. Use a jumper wire:


(phone app link)I agree.High, or low? That suggests that NOT all the connections between the batt. & alt. are clean.
(phone app link)


(phone app link)Not at all. It sounds like a bad battery, or dirty terminals.


(phone app link)The way that's molded into the regulator case:


(phone app link)

Diegopy94

Sorry for my absence life has just been busy.
was busy with work and didn't touch the truck for a few days. When I went back to tinker with it, it was holding a charge and driving fine but I didn't believe anything I had done had fixed it.
i tested the voltage regulator and it passed. then on my next day off I finally pulled and cleaned every connection between batt, alt, starter, starter solenoid, and the motors ground.
wile everything was apart I tested all wires for continuity wile wiggling them around to find shorts but they all turned out fine. Now I had more faith that it ought to be running good instead of magically fixing itself over 2 days of not looking at it..

thanks for all the links Steve!!