Hello all. Long time listener, first time caller. I’ve been searching threads but haven’t found anything specific regarding. I just picked up a 96’ 312 6GK01600 Feels weak and bogs down under load. (Maybe I’m expecting too much from a 27yo machine.) Stalled engine under load. Turned key off and set for a minute before attempting to restart. Turned key to on position and no power to panel, no alarm. Took about 10-15 min before the instrument cluster regained power. Turned key to start and dead battery. Removed batteries and set them on a charger. Charged to 100% 12.8v. Placed back in and it started right up. Panel is faded and I noticed the glow plug and battery symbol were on but wasn’t for certain as it was dim. Ran the 312 for about 10 min and then it died. No power to anything. I isolated the batteries and they tested 12.8 and 100%. Ground on frame is rusted so I plan to clean that up. Didn’t have tools to remove the panel and check fuses. Breaker is sticking out and doesn’t stay in when pushed. Anything else I should check? Would low voltage or poor ground cause the power concerns I have? Appreciate any and all feedback.
Ordering a breaker to have that on hand just in case. Sorry for my ignorance. New to this and trying to learn.
might be off on this machine but most 24 volt system and batteries need to be at 13 volts to 14.5 volts. being off by .2 volts on some machines will not let it start. try jumping it to start but volt test the jumpers.they should be above 13 volts. not all trucks put out that, we ended up getting a suv to jump a tractor 1 year. bateries where ok but not high enough to engage the electronics. run time and stalling is generally a heating issue and can be many things from temps, to alt. its a process of elimination.
Was the 12.8v on a load test of each battery (it's a 24v system) or just putting a meter across the terminals.? I'll send you an electrical schematic. Keep an eye on your messages.
Hey Nige! I removed the batteries and charged and tested individually. 12.7 & 12.8 is what they tested as 12v
But was that with a simple multimeter or a proper battery load tester.? The second of those testers puts the battery under load. A battery can show up good but collapse when put under load. Just sayin'.
Volt meter and charger read out. I’ll take em in as I don’t have a load tester to verify. Good call
Will low system voltage have an adverse effect on the hydraulic output?
yes, if there is computers, solenoids or sensors involved it will throw everything off. not as much electronics on those older machines but enough to send mechanics going in circles for days when its as simple as check load test on batteries and replace then can get accurate readings and checks. low voltage does a lot of damage to any electric over hydraulic system. it can prevent valves from fully opening. also once you verify the batteries, start the machine and use a kill switch or take the batteries leads off. if machine stalls alternator is bad. theres been alot of alternators testing good but are not. not sure why all of a sudden parts stores are saying good when clearly there not. a lot of bad tests that can be proofed. if disconnecting cables be careful. shocks can be dangerous. once you rule out those 2, then its onto other areas of the machine.
see if its charging turn all the lights on cab fan on and connect a load tester across the battery's at the 24v side load up the system and using a ac volt meter see what being put out.....charging battery's then testing voltage proves very little they need to be load tested read the rated cca on the battery load it up to about half the rated cca read on the load tester what the voltage is anything less that 9.5 bin it and replace always replace in pairs
Thanks y’all. This is inline with my thoughts and would explain the performance issues. 1:Load Test Batteries 2: Clean up ground to frame for good connection 3: Test/Replace breaker. 4: Test alternator output Ruling these out before moving on. Anything else? Appreciate the feedback.
Sorry I may have mislead you on the alternator test......while you have the alternator loaded up and running use a amp clamp on the alternator output wire see what you got for amps....compare to factory spec or if the correct alternator is installed and the tag is attached for its max out put your golden
go thru the electrical diagrams and cleanup all the ground connections. some alternators have a ground. others just use the mounting hardware to ground. i have had to pull brush up contact points on a alternator. make sure engine to frame ground is good. inspect the harness and observe its location as well. if its mounted up, and clean its going to be ok, if its in the bottom in oil and dirt well that can create a a problem. especially if the spare mouse made a home at some point. if theres buildup as most machines have, pressure wash it clean. make sure batteries are disconnected. let machine sit for a day or 2. biggest mistake people make is start right after cleaning and 1 knick in a wire can either start a fire or grenade a machine. i always warm up a machine, so it dries down faster. its all a process of elimination. the more things you eliminate, the fewer things problems can be. i have seen a lot of dealers miss grounding issues on equipment just to right off as a loss/ unfix able. it will also slowly damage a new set of batteries over time. to save time the order i would approach this is, batteries, verify alternator works. get those 2 done. then get into the cleaning stage. its good to do every few years. use either a electrical coating on grounds once tightened down, or use simply tube grease. i typically use tube grease. theres dielectric you can get, but it all works the same. keeps the corrosion from happening.
Quick update: Both batteries checked good under load. Ground to frame stud snapped due to corrosion and 2 grounds from wiring harness were missing ring connectors. Drilled hole in frame and will tap it to connect grounds too. (Will weld when I can) Repairing harness grounds. Fuse #15 blown- replaced. Alternator grounds to mount. Looked good.
Check alternator. Quick test: Start machine. Put voltmeter on it while idle (or slightly faster), it should read 13v and more.
No dice. Repaired ground connections and reinstalled. Batteries installed. 25.3v with multi-meter. Key to on position and instrument panel has power. Alarm sounds. Key to start, engine attempts to start and instrument Panel loses all power. #15 10amp fuse blown again.
#15 is ignition switch
Forgot to update. Issue was a faulty Fuel Shut-off Solenoid. Replaced with off-brand because Cat wanted $400. Engine started and no longer struggles or feels underpowered. Thanks all for the assistance!
Thanks for the follow-up...good to find out what fixes things.
Yessir. Hopefully it helps a future search.