Electrical Gremlin?
Thread Starter
|
Mountain Pass
Joined: Feb 2004
Posts: 164
Likes: 0
From: Spokane, WA
Electrical Gremlin?
OK, so I've had a mysterious battery drain going on for a while. In the summer, if my truck sat for 2 or 3 days the batteries would be dead and I would have to charge them or get a jump. Now that it's cold, they will be dead in about 8 hours. I go in to work come out 8 hours later and no start. Sounds like a battery problem. Well, a load test shows the batteries are good. I have put on a new alternator (old one was bad) and starter. Using a multimeter, I have pulled fuses and tested for a current draw. Only draw was radio. It was drawing .02 amps, not enough to kill it that fast I would think. The GPR tests good. I tested glowplugs and #8 is bad. Last night I charged batteries with the cables off. This morning they show 12.5 volts each. So, I hook them up and truck wouldn't start. Hmmm, can't be the batteries. Right? It just doesn't have the power to crank over on it's own. When I jump start using another diesel or 2 cars, it gets plenty of power and fires right up. Has anyone had a similar problem or any ideas what to look for. I have been reading other posts and have ran out of ideas. Sorry for long post, but I wanted to get all the details in here. Thanks
Laughing Gas
Joined: Aug 2009
Posts: 1,192
Likes: 7
From: Belgrade, MT
Test While Cranking
Might put a volt meter on the batteries while trying to crank and see how low the voltage goes, if it drops below 10.5 volts I don't think it will fire.
Also, might check the ground cables where they terminate on the frame and clean.
Tom
Also, might check the ground cables where they terminate on the frame and clean.
Tom
Hotshot
Joined: Jul 2003
Posts: 12,177
Likes: 40
From: Newport, WA
With a fresh charge on the batteries and no fire this AM without jumping it, I'd be tempted to think they are the culprit. How old are the batteries? Even if they load tested okay, they might still be suspect. I'd start by cleaning the terminals and cable ends up real good and see if it helps any. If you could swap batts with another rig temporarily just to eliminate yours as a potential problem that might help too.
Thread Starter
|
Mountain Pass
Joined: Feb 2004
Posts: 164
Likes: 0
From: Spokane, WA
I went out at lunch to check volts while starting. 12v prior to start, dropped to 10.5v while wait to start light was on, then dropped to 6.5v while trying to crank. It didn't even try to start. Even though they test good, just must not be putting out the power to start. I guess I'll have to get another pair of batts to swap out and check it. The batts in it are 1.5 yrs old.
Post Fiend
Joined: Nov 2007
Posts: 9,549
Likes: 14
From: Payson, AZ
If it starts with a jump that eliminates everything but the batts or the negative batt connections if you used a frame ground or engine ground for the negative jumper cable. If the voltage drops to 6.5v then the batts did not pass a real load test.
Trending Topics
Thread Starter
|
Mountain Pass
Joined: Feb 2004
Posts: 164
Likes: 0
From: Spokane, WA
I was like "really that's it for the test".
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Post Fiend
Joined: Nov 2007
Posts: 9,549
Likes: 14
From: Payson, AZ
Also keep in mind that one bad battery has a real negative effect on the other battery. It can discharge it while the truck just sits or keep it from charging properly while truck is running.
Hotshot
Joined: Jan 2008
Posts: 13,144
Likes: 11
From: Rochdale MA
Another thought is to feel the alt in the am or after it has been sitting for the 8 hours that you are at work. If the alt feels slightly warmer than the ambient air temp then the diode in it is gone and that is draining your batteries.
Post Fiend
Joined: Feb 2007
Posts: 7,191
Likes: 4
From: Blairsville,Ga
Just about leaves 1 or more bad batteries
Fleet Owner
Joined: Sep 2005
Posts: 28,609
Likes: 18
From: Lake Tahoe, Nevada
I went out at lunch to check volts while starting. 12v prior to start, dropped to 10.5v while wait to start light was on, then dropped to 6.5v while trying to crank. It didn't even try to start. Even though they test good, just must not be putting out the power to start. I guess I'll have to get another pair of batts to swap out and check it. The batts in it are 1.5 yrs old.
I would say that is a definitive test in itself! Bad batteries.