Charging and starting problems-please read my voltage numbers.

[Explorer_PL]

Few weeks ago, I had to jump my 06 v8 twice in the morning when it got really cold. I had an Interstate good quality battery that was installed 20 months earlier. I went back to the shop where I bought it and they warrantied it and just gave me a new one. I thought I was good to go, but the next day the car hesitated and eventually started but something was not right. Since I drive every day it starts every morning but there is that hesitation and it cranks for few seconds lately.
I went back to the shop to do load test, but instead they disconnected the positive cable and put a light probe between the + cable and + post and the probe lit. They closed the doors, shut down the car and expected that the light would go off or dim down but it stayed lit. They concluded that I have a short somewhere and it's draining the battery. The voltage whit engine running was slightly over 14v so they concluded that the alternator is OK. Since they were closing for the day, I took the car home to see if I can trace the short.

With the light probe in line and lit, I removed every fuse and relay one by one under the hood and under the dash, but the light never went off, and the current read slightly under 1A . Since I have another explorer 07 v6 i decided to do the same on the 07 and it read slightly under 2A with the key off and doors closed. That makes me think that the draw is normal and I do not have a short.
I started both cars on and the 07 v6 that has no problems starting read 14.5 v on the battery, while the "problem" v8 read 13.69 v with the engine running, and sometimes 13.1
This is still the original alternator that came with the car in August 2005, 257k miles ago.
Is the mid 13v readings too low and that may be my problem ?

 

[boominXplorer]

What kind of condition are your terminals at the battery in? Corrosion can cause weak battery symptoms.

 

[Explorer_PL]

Very clean, no corrosion.

Thanks.

 

[shucker1]

If I am not mistaken there is a "Keep Alive Relay" involved.

Basically once you take the keys out and close the door a timer starts and after about 10 minutes it makes sure to kill power to stuff like dome lights and things you may have accidentally left on.

1 Amp draw seems on the high side to me.

You may want to try and test again by taking and initial reading and then doing it again about 10-15 minutes after the first.

Using a multimeter in series with the battery connection is the best way to check for current draw.

 

[boominXplorer]

^^^^ He is right, have to wait 10 or 15 min. Max normal draw Ford spec is either .6A or .8A (can't remember). 05+ Mustangs have a draw issue that comes from the interior fuse block, it's super common and saw it a few times over the years I worked in the stealership.

 

[Explorer_PL]

Thanks, great tips.

That would explain why I see over 1 amp initially on the "good" 07 and it starts normally.

Is 13.7 low for the alternator ?

 

[boominXplorer]

Above 13.5 is good. I haven't had the best luck with interstate batteries.

 

[Explorer_PL]

Are the units on the 4.6 130A or 200A ?

 

[MotorCityFats13]

Are the units on the 4.6 130A or 200A ?

from my looking into HO after market alts all explorers between 06-09 are 130amp units stock and 2010 were 95amp...... my 07 likes to charge around 14.4 cold and drops down to 14 and with acc's running sometimes reads 13.5, I don't like this one bit but never a problem starting even though the resting voltage of my AGM always reads 12vdc and I for sure would be more happy with 13vdc........... I put a trickle charger on it one day for 24hrs and didn't drive it for a day and it did keep a standing charge at 13vdc but after I started it the charge brought it back down.... I feel the charging systems on these explorers are complete junk and cant stand PCM controlled alts

 

[michael loibl]

PL... I just finally replaced my original 2006 alternator last month on my V6. It had been weak at idle for 2 years dipping into the low 12’s and even high 11’s with lights on, but never a charging system warning on display, which always surprised me. It always came up to acceptable levels around 1,300 RPM, and into the 14 volt range by 1,500 RPM even with lights and blower on.
With the winter season upon us (lights, heat, rear defroster, wipers, and stop&go traffic thru Bergen County) I came to my senses and replaced it. 100% operation now even with all accessories on at idle.

 

[Explorer_PL]

Almost ashamed to post an update but .......

I traced the issues to the positive lead on the starter. Somehow the 13 mm nut worked itself loose on the constant + post on the starter, I tightened it back and it was great for few days.....

Now I have no crank no start situation....

See my new post.

 

[07EddyB]

I was like - What new post? - I couldn't find it! Then I realized you made this post 6 minutes ago.

 

[Butch-Explorer]

My 06 V8 did the exact same thing, but i kept getting the P0620. I replaced the battery and right after that, the alternator stopped charging only 12 volts. Replaced the alternator with a tested reman unit at 173 amps for less the stock 130 amp. All good now even with these 10 degree temperatures here now.

 

[Butch-Explorer]

My 06 V8 did the exact same thing, but i kept getting the P0620. I replaced the battery and right after that, the alternator stopped charging only 12 volts. Replaced the alternator with a tested reman unit at 173 amps for less the stock 130 amp. All good now even with these 10 degree temperatures here now.