[swolke]

I have an 89 XLT 5.8. I have been experiencing issues with my accessories (blower motor, wiper blades, power windows) killing my charging while the beast is running. After short trips even with the accesories off, the car does not really want to turn over, however if you leave it for an hour or so, it fires up like a champ. With-out running any accessories I am charging at 14.3. Just put in another 75 amp alternator {internal voltage regulator(old one was fine but from Autozone so tired the Napa alt)}. Even after installing the new alt i am still seeing a charge drop from 14.3 to between 10 and 11.5 volts. Once the accessories are turned off, the needle goes back to 14.3. I have already replaced main ground wire, main power cable, pulled all fuses one at a time to test each system for a bad ground or bad drain, new alt and new heavy duty batt. Any ideas?
THNX

 

[sewiv]

Bad starter?

 

[swolke]

Its more like it does not have the juice to turn the starter over, ussually it fires but just struggles a bit.

 

[sewiv]

That's what a bad starter acts like. Pull it, take it in for testing.

 

[Streetgang]

Put a 160A 3G alt on that bad boy ASAP!

 

[k1w1t1m]

I am going to go with everyone else. Do a new starter first and then upgrade your alternator. I have noticed my blower motor drags the voltage badly. BTW Fords are known for their hot start issues with the starter.

 

[swolke]

ALrighty. Replaced the starter. No more restarting issues when the truck is hot. However, blower motor, turn signals, lights (basically any accesory) is dropping the voltage down 1 to 1.5 volts. Any new ideas?

 

[kf4amu]

I think thats about normal drop for the crappy 2G alternator you have on there. Just because it says 75 amps doesnt really mean its 75 amps.

Do the 3G upgrade. You'll be glad you did.

 

[Steve83]

Amperage to run the truck doesn't necessarily come from the alt - the battery is capable of putting out 200-1,100A. So even with a 20A alt, a 100A draw won't necessarily drop the voltage that much.

But high resistance in either battery cable will cause it to drop, because the VR relies on them to get an accurate reading of the battery voltage, which is the basis for what it does.

Exactly where & under what conditions did you measure this 1-1.5V drop?

 

[swolke]

I am seeing the drop on the in dash gauge.

 

[kf4amu]

Oh well dont worry about it. Dash gauges suck.

 

[Steve83]

Until you start checking with a DMM, don't worry about it. There are no numbers across the factory gauge for a reason: it's not calibrated. It's just a "gauge".