Whenever I 1st start my 2004 Screw 5.4L, my battery guage stays a little on the low side, and then after about 5-7 seconds, it will slowly rise back up above 1/2 where it normally sits. If I look at my Edge box, at initial startup, my Volts read 11.2 (with the engine idling at startup)....then the numbers slowly climb within 5-7 seconds up to 13.8 or so where it should be. Has anyone else had this concern, and if so, what fixed it? I really cannot afford to put an alternator in this thing right now, but, my theory always was that if an alternator goes, it usually goes...why would it not charge at startup, then all of sudden charge good and be fine for the rest of the driving cycle?? Thanks!!

Mr86GT

 

I would say that you alternator is working fine. Since it brings your voltage back to
13.8. What are your volts before you start the truck? If it is below 12, then I would
take you battery to AutoZone or someplace like that and have the battery load tested.
Normal operation, would be that the battery will drop volts at start up, and quickly build back up with the alternator.

Good Luck

MC

 

Well, when I turn the key and hit the starter, the Volts drop to about 7 during cranking...but once the engine fires, it SHOULD jump right to 14...my ZX2 and Mustang both have AutoMeter Volt meters on them (yes, even the ZX2, ahhaa)...and they behave that way. However, according to my factory Volt meter in the truck....AND my Edge....it takes about 5-7 seconds AFTER the engine is fired....to slowly creep back up to 13.5-13.8. If the automatic headlamps are on at night....my dash lamps even are dim until that 5-7 seconds have elapsed....then once the factory Volt guage creeps back up to above 1/2 where it normally is....the dash lights go back to bright....the Edge reads 13.2-14 and everything is fine after that. I just find this strange...b/c my other cars jump INSTANTLY to 14 right after the engine fires. Ya know??

Mr86GT

 

It will jump back up if you have a good battery. It sounds like your battery is going south.

 

7V seems really low for cranking. I usually don't see anything below 10.5-11 on most vehicles I have looked at. Could be the battery or a high resistance
(corroded or loose) connection on one of the cables. If you have a DVM, you could measure the voltage at the actual battery terminals - not the cable ends. If the battery itself is going to 7V, I would say it has one foot in the grave and the other on a banana peel. If the battery itself turns out to be normal, then I'd start looking at the connections and cables.

 

Checking battery/starter cables goes without saying if you are experiencing a voltage prob. First thing to look at not matter what your electrical prob is when it is a starting/charging prob. Usually the battery is the culprit if the wires/cables are good. I have a cheap battery checker at home, and have found a bad battery before I have headed for the store. Even hooking up a charger to the battery and observing that all of the cells have bubbles in them will indicate a bad cell. (It is usually one of the post cells that go bad). Just dont hook it up with the caps off, or you could lose your eyebrows.

 

I was having similar problems with mine. It seemed to have difficulty turning over in the morning, and finally didn't start after I washed it and had the radio on for about 30 min yesterday. I went to autozone and got a 875 cca battery and it fit perfectly. I was even able to put the battery cover back in place. Cleaned the connectors and smothered them and the terminals with electric grease. It starts right up now and the volts don't drop past half when starting watching the voltage gauge .

 

The 5-7 second delay is probably do to the fact that these trucks have what they call "smart alternators". The PCM monitors the alt and controls the regulator.