I bought my 2020 F350 6.7 new and I've put about 28k on it. I haven't had a single issue with this truck until now. Sometimes the truck sits for a day or so without being used and when that happens it's a "weak" start. It always starts (knock on wood) but the last thing I want is to be on a trip pulling the FW and it doesn't start. There is no code. It has 2 batts and frankly I don't know how to test voltage on a 2 battery setup and voltage isn't always the best indicator anyway. And I do know, if one batt is bad it drags down the other. I've also read that these trucks have had issues with the starters. It's still under warranty and I was told to make an appointment for a diagnostic test. But I trust you guys more than I trust a dealership and thought I'd throw it out there to get your thoughts so they don't brush me off. Also been noticing intermittent hard shifts into 3rd on a slight grade. Again no code, but I have heard there have been issues with these tranny's and intermittent hard shifting. I plan on asking them about it, but again, always worry about an honest opinion from the dealership. They always seem to find stuff when the warranty is over, but funny how they can't find the issues when it's covered.

If I was going to check the batteries I'd unhook the negative terminals on both batteries after parking it. A couple days later I'd check each battery individually. They should read 12.8 volts. My 2011 had its batteries replaced under warranty at just under 3 years old. It would only crank momentarily and if it didn't start the computer would cause the starter to cut out due to low voltage.

It could be the batteries or you could have a parasitic draw somewhere that draws down the batteries as it sits.

So it cranks slower after sitting for only a day, but cranks faster if started within the same day as it was run last?If that's the case, it is not the starter, it is the batteries.If you dont want to test them, and suspect bad battery/power draw, just let it sit for a few days and see if it's worse than 1 day. Otherwise, check battery voltage of each battery separately and/or have them load tested.That's where I'd start (no pun intended, lol)

My local auto parts store is literally a mile up the street. I'm certain they are better at doing a batt test than me. Does it make sense for them to check the batts before making an appt at the dealer and possibly leaving it there?

So you have an intermittent "crank, no start".• Check the battery voltage at both batteries. It should be identical. • Does it crank a "full speed" or is it cranking slower ?• The time that it did not start, what did you do to make it start ?

2020 F350 6.7 weak start | Good Sam Community

thomasmnile
Explorer
Apr 11, 2022
Have both batteries load tested?

Parasitic draw? What vehicle built these days doesn't have them? So many computers and stuff in vehicles now....

We have a 2019 Highlander. Was sitting in a parking lot waiting on my wife while she was in a fabric store. Ignition in accessory position, radio on nothing else. The master alarm suddenly goes off and the dash display pops the following message " shutting Ignition off to conserve battery". Radio only????? After 20 minutes????

Good thing I can stream Sirius XM on my phone. Geeez.......
Bob_Olallawa
Explorer
Apr 11, 2022
way2roll wrote:
I bought my 2020 F350 6.7 new and I've put about 28k on it. I haven't had a single issue with this truck until now. Sometimes the truck sits for a day or so without being used and when that happens it's a "weak" start. It always starts (knock on wood) but the last thing I want is to be on a trip pulling the FW and it doesn't start. There is no code. It has 2 batts and frankly I don't know how to test voltage on a 2 battery setup and voltage isn't always the best indicator anyway. And I do know, if one batt is bad it drags down the other. I've also read that these trucks have had issues with the starters. It's still under warranty and I was told to make an appointment for a diagnostic test. But I trust you guys more than I trust a dealership and thought I'd throw it out there to get your thoughts so they don't brush me off. Also been noticing intermittent hard shifts into 3rd on a slight grade. Again no code, but I have heard there have been issues with these tranny's and intermittent hard shifting. I plan on asking them about it, but again, always worry about an honest opinion from the dealership. They always seem to find stuff when the warranty is over, but funny how they can't find the issues when it's covered.

I think you should make the appointment to get it checked out. Maybe they will find the problem and take care of it.
theoldwizard1
Explorer II
Apr 11, 2022
So you have an intermittent "crank, no start".

• Check the battery voltage at both batteries. It should be identical.
• Does it crank a "full speed" or is it cranking slower ?
• The time that it did not start, what did you do to make it start ?
way2roll
Navigator II
Apr 11, 2022
My local auto parts store is literally a mile up the street. I'm certain they are better at doing a batt test than me. Does it make sense for them to check the batts before making an appt at the dealer and possibly leaving it there?
Grit_dog
Navigator
Apr 11, 2022
So it cranks slower after sitting for only a day, but cranks faster if started within the same day as it was run last?
If that's the case, it is not the starter, it is the batteries.
If you dont want to test them, and suspect bad battery/power draw, just let it sit for a few days and see if it's worse than 1 day. Otherwise, check battery voltage of each battery separately and/or have them load tested.

That's where I'd start (no pun intended, lol)
ksss
Explorer
Apr 11, 2022
It could be the batteries or you could have a parasitic draw somewhere that draws down the batteries as it sits.
4x4ord
Explorer III
Apr 11, 2022
If I was going to check the batteries I'd unhook the negative terminals on both batteries after parking it. A couple days later I'd check each battery individually. They should read 12.8 volts. My 2011 had its batteries replaced under warranty at just under 3 years old. It would only crank momentarily and if it didn't start the computer would cause the starter to cut out due to low voltage.

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2020 F350 6.7 weak start

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