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Discussion Starter #1
2000 f250 7.3 stock engine aka my trouble child.

Since June 2020 I've put in 3 brand new alternators from Napa. Everytime it's the same issue, volt regulator stops working, but I'm starting to wonder if there's something more to it. The last alternator was put in in October and the 3rd put in in November. Truck sits around 14.2 volts when running and even with new GP and block heater she doesn't wanna start at 20° let alone 0°. Anyone have any ideas? I'm getting pretty tired of throwing 1000s of dollars a year at the truck, tools, and the doctor when its too complicated or time consuming for me.
 

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Slow/no start when cold COULD be worn injectors. That, along with dead glow plugs, was the problem with mine. I did the injector shim kit referenced in the Sticky threads at the top of this forum and it has made a huge difference in how fast my truck starts. How many miles on the injectors? How old are the batteries?
 

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So how many problems do you actually have? A starting problem or a alternator problem?

A bad alternator won't cause it not to start.

Sounds like you need to do some trouble shooting instead of throwing parts at it.
 

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I believe that your batteries are junk. Alternators will last many years. What happens is batteries go bad and the alternator has a hard time maintaining a charge. Which in turn burns out the diodes. You can have batteries tested and they may still be junk. If your batteries have been discharged to many times or you dont get them to full charge before starting your truck than that is what kills alternators. Rule of thumb, If you need a new alternator than replace the batteries at the same time.
 

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I've been chasing problems since I bought the truck in 2017. Both batteries were changed in June 2020 and glow plugs were changed in October 2020 but as hard as the batteries cranked the last time I tried I'm wondering if the starter took a **** too
 

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Try plugging it into a battery tender, too. That way you know the batteries are charged before you start
 

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Bad starter is a definite possibility. If it's the original starter, that's very likely.
If it's not cranking fast enough, that will cause a hard start when cold.
 

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So are you making the choice to keep replacing the alternator for a starting problem or is a shop/mechanic telling you to do it?? If it is a shop /mechanic do not go back. If it is your choice you need to post here before throwing parts at a problem. I would agree it is a starter issue.
DENNY
 
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My question is similar to the above.
How do you know the voltage regulator keeps failing? What is happening to your voltage?

Also, did you test the GPR when you replaced the GPs?

And have you tested your block heater for continuity? Often times the cord fails. IIRC, you should get about 1100 Ohms? I always have to find a Bugman post to be sure 😁
 

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I only know the voltage regulator keeps going out because the alt will hold volts within at 13.5v - 14.7v range when idling but will spike to 18v when accelerating. I changed both batteries and alt the first time after both were pretty much cooked trying to get to a parts store in the boonies. Second time I just changed the alternator cause the batteries passed a load test. I did a continuity test on the block heater and it failed. But I'm chasing a multitude of problems on a truck that was neglected for 20 years. I swapped out the block heater cord today and cleaned the terminals, and after about 5 hours heating, she started but not before seeming like she was gonna die from lack of battery power. I don't mind throwing parts at it if it'll fix the issues. Only real guesses I have left are battery cable and starter.
 

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The guys here will have you throw money at just the parts you need👍

And, yes, those voltage spikes are the confirmation.

What is the cost of a NAPA alternator? I learned this past year that NAPA now has a cheap line of parts to compete with AutoZone type stores and then they continue to have a high end line of quality parts that the repair shops use and get discounts on.
 

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Maybe someone will post with a starter recommendation.

BTW, NAPA allegedly gives 10% off for AAA members...I say allegedly because my local store always says that does not count for online purchases.
 

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I think it was somewhere in the $300-$350 range. Napa warranty keeps replacing the alternator. I just want to get the starting issues fixed once and for all so I can move to a new set of issues.
 

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Understood.

NAPA has several options of alternators and I was trying to determine which one you have based on price.
 

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Thats not necessary but thank you.
 

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It starts hard in any weather from -40 - 115°
That's another reason to suspect the starter. Slow cranking speed in any temperature equals a hard start.
On your voltage spikes, I'd be sure that all your wiring connections are clean, including grounds. If there's a high resistance connection between the alternator and batteries, the alternator will try to increase voltage to overcome that resistance. That will kill an alternator as well.
 
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