First off, 2007 F-250 6.0L 63K

On to the problem:

Today (and maybe yesterday), each time I cranked the truck, it sounded like the batteries were getting weaker. This is after driving at highway speeds for some time. Finally after spending the evening catching redfish, the truck barely cranked at the launch and wont crank now (or even attempt to crank). Battery voltage is 9.5 on the dash (holding the two buttons and turning the key on). I plan to pull the alternator and batteries for testing tomorrow, but wanted ya'lls opinion due to the fact it will be at oriley's (brother works there). Im suspecting the alternator, but never got any warning lights, indicators or anything else. After searching the forums, it appears you normally get some kinf of idiot light. Truck ran great on the way home with no apparent problems and all connections seem good. Any idea's?

 

I'd suspect the batteries. Load testing will tell the story.

 

Belt tension driving the alternator??

 

same thing happened to me. turns out alternator was only putting out like 10v and drained batteries down. went to leave work and truck was dead so i drove company truck all weekend. but worst thing about mine was it took the ficm with it.

but if your going to pull them both there is no need to waste time debating what caused it.

 

I would say batteries not taking charge. If the alt is bad the truck would die while running (in most cases any ways). The alt maybe putting out enough to run the truck, but the batteries not taking the charge.

 

Batteries can be frustrating. If a bit aged they can sulphate. Even when new they can be defective. I had to put two new batteries in two motorcycles this year and in each case the first new battery was defective (sulphated in weeks).
My new mustang had a bad alternator so they can go bad even new.
Check the grounding, poor / bad grounding can be source of all electrical evil.

 

There is no way to claim it is battery, alternator, or something else without systematically testing / eliminating issues.

Pigtail / wiring is very high on the failure list.

More than once, I saw alternators / batteries tossed out multiple times because of that issue.

Do the homework --- which include a through test of everything, not just the battery and alternator.

Unless you like doing the job several times!

 

sure there is ,, no light on the dash indicates it's charging while running ,, low voltage as He tested while not running points to batteries
not definitive but thats my bet also

 

The key to troubleshooting is prioritiztaion!

Being that it is a 2007, batteries seem the most likely. Unless it has had a hard life in 3 years, things like harnesses, connecters, etc. are much less likely. Many people have the OEM batteries fail right at the end of the warranty period.

Load test the batteries individually, check each cell w/ a hydrometer (if you have one, if not EZ Red makes a cheap one) and go from there. People should test their batteries once a year (minimum) anyway. While you are disconnecting the batteries - inspect the things miner999r & gearloose mentioned (grounds, wire chaffing, corrosion, loose pigtails, etc).

JMHO

 

That can also be caused by a failed sense wire connection.

Suppose the failure is inside the pigtail.

It will be impossible to detect unless you can see through the plastic if it is intermittent --- it can read fine on a voltage test at the connector while static, and then, in dynamic (engine running) fail.

Identical symptoms, but you would have replaced the alternator before you check voltage / contact / integrity of the sense wire.

You can, X-Ray the part, use other imaging techniques like Gamma Ray scans, etc.

Your choice.

Throw parts on it and see if it sticks...

Or do the diagnostics right to begin with.

PS I do not have a portable X-Ray or other imaging device.

 

Mark

That is the right prioritization for a pre-2004 vehicle.

Post 2004, you will find that the quality of wiring / connectors / etc. plunged as metal and commodity prices spiked.

I am seeing a lot of premature failures that lead right back to the use of under gauged / poor quality wiring and connectors.

That is why I changed the prioritization --- and have a broader range of suspects.

But then... I also gossip with connector, wiring, and other electro-mechanical component makers that supply the industry, and specifically, Ford.

Not facts that persons outside of the industry will know readily.


PS The other nite, I had a drink at the bar with a connector guy who supply, say "big 3".

Failure in connector caused by ASIC failure... a doozie of a story.

I am not allowed to reveal information so that the guilty can be protected.

 

I am just stating the most likley culprit specially on an 07 without writing a book .. and doing a "what if "scenario

 

I will just have to disagree w/ that. There is no way that 2006 and 2007 vehicles have failure rates in these electrical components you describe at a rate more frequent than the battery life span. Maybe in some periodic instances, but not as a whole.

Anyway, my emphasis was to test batteries routinely anyway, so starting there is best IMO. Besides, your FICM depends on good batteries!

 

We are not in disagreement.

Battery lifespan is right up there and I would actually do as you suggested.

Ruling out batteries take very little time charge it up, and then, load test it --- even if the "load test" is not definitive --- and it should be always done first.

Most load testers (especially the portable ones) only simulate a fraction of the power draw and time of a real 6.0 engine system at starting / cranking / glow plug etc. on.

So sure --- rule out the batteries because it is cheap and easy to do.

You are right on that one!




But replacing alternators? Let's think about that.

The standard MO is to chuck the alternator once batteries / battery cables are ruled out.

Few persons have the capacity to do a proper bench test of an alternator.


Or have the special tools I created to test an alternator while it is "on car" without removing it.

So the default is just to chuck it if the voltage as read is not "to spec".



For post 2004 vehicles, that is no longer right.

In fact, by replacing a factory Ford OEM alternator with an aftermarket (when the OEM is working fine) is almost asking for trouble because many (most) aftermarket non-Ford alternators are in fact, far below Ford spec.

Subtle things like duty cycle, bearing life, etc. that is not in the spec sheets at retail.

FYI, I checked the original service record for mine, and the Ford OEM alternator lasted 240,000+ miles, when finally, the bearings gave out.

The replacement alternator lasted about 1 year.

So I am very hesitant to chuck out a Ford OEM alternator until I know something else is not the cause.


Weigh the OEM Ford alternator against the standard replacements (regardless of claimed output) ---- you will find a drastic difference in weight ---- not a perfect, but a useful gauge of quality and duty cycle.

Alternators simply cannot be made with very little metal (mostly expensive copper) unless duty cycle is compromised.

Hence, in most cases I have seen, the replacement of a Ford OEM truck alternator with an aftermarket one is a drastic step downward in reliability.

The choice comes to, buying New Ford OEM (not even rebuilts), and paying them... or, ideally, avoid unnecessarily tossing out a perfectly good Ford OEM alternator to begin with.



Historically, Wiring / Connector issues use to only happen well after the warranties expire (3/36) or after 7 or 10 years.

Issues are now arising much sooner.

So whereas wiring and connectors would be one of the last things to check (or not even checked prior to chucking out an alternator), I now routinely check it for any vehicle that is post 2004, or have high mileage.

More often than not, I have "fixed" alternator and like problems by just fixing / cleaning the wiring and connectors.



I don't even want to think about wiring and connector issues in the post 2008 ones --- where the buying decisions were made in 2005/2006 close to the peak of commodity prices.


Just watch --- there will be a rash of failures coming down the road.



Best regards.

 

If you'll remember the mid 80's to early 90's alternators when replaced came with replacement pigtails in the box. This included a/m alternators. I have changed the alt. on 86 Grand Marquis and 91 Ford pick up. Both replacements came with new main pigtais that you had to solder on.