Hi all, I'm having an issue with my 420d. Its a 24v system (military). I've tested voltage and it reads 20-22volts haven't checked amperage. Currently will not start on its own. When jumped with "freedom" cables it starts fine and runs fine. Check voltage again it alternator is working. Judging by the state of the engine and accessory parts the starter is the newest part on it, brand new actually. One known issue is a broken/almost rotted bussman 120a to ecu connection. I'm working on getting a new one but I would appreciate any troubleshooting ideas. I need to pull the vin as I know there are 5-6 diff electrical diagrams. I've heard about fnr, but again the issue with electrical system. I can pull the floor panel but I would be looking at solenoid a without any knowledge of what is what, same goes with the fuse panel. Need to check fuses though as the cab has a distinct burnt electrical smell at the moment. I hate working on someone else's project, I also have a skidsteer that someone put gas instead of diesel into. Operator had it running for 30 minutes then started overheating. First thing I checked when I got to the piece was the fuel tank. Smelled like gas, stuck a zip tie into the tank, pulled it out and sure enough i set it on fire. I'm hoping I can just drain the tank/lines and she'll work again. Advice advice advice!!
Need to add on another question in regards to the 420 since I've been reading past issues. If the shifter is the problem is there a way to test it? Thanks in advance
20-22v on a 24 is like 8-10 on a 12V system, that's a bad battery. Is that voltage reading on a multimeter or a dash gauge?
Multimeter. Initially read at 22.58 and would engage the starter but no go on fire up. After a handful of starting attempts it went down to 20ish. Hooked up freedom cables ran for about 10 minutes and voltage was 23-25 while running. Shutoff and tested again and back at 22. When I test each battery individually they read around 10.20ish
When running, voltage should be about 28, when stopped, it should be about 24.5. The individual batteries should be about 12.2 fully charged and shut off. You probably need to buy 2 batteries, but the only way to know for sure is to charge them up and take them to be tested. You have to have a load tester or inductive tester to see if they are bad.
What does the voltage do WHILE cranking ? If it takes a dive, it more than likely is a bad battery if it starts normally when jumped. You can get close to normal voltage on a bad battery without load, but have it take a dive when loaded. It's the same as performing a 'load' test on a battery. I Agree with Mitch on the voltage comparisons.
I'd have to agree with Mitch...... which is hard for me to do!!!! :tong
Those voltages are all low. 23-25 volts is a wide range for running but most likely the alternator isn't working (or the wiring? that's a whole 'nother can of worms). Easy to test, hook up a battery charger for several hours, or overnight, and then see what it does. start on it's own? running voltage starting with fully charged batteries?
A 24v system should be minimum of 26-27v while running. Sounds like both batteries and alternator (or wiring between alternator & batteries maybe) could be toast ..............but wait ........... I agree with Delmer, get a trickle charger on it for a minimum of 24 hours and see what the battery voltage does. Who knows, you might kills 2 birds with 1 stone..?
I agree about the battery charger, but if the batteries are bad enough, I have seen them cause running voltage to be down a volt or two. We know the alternator is doing something because running voltage is higher than standing voltage. Realistically, if it was here, and my battery tester wasn't, I'd swap in a couple batteries out of something else and see if that fixed it. I bet it would.
More troubleshooting. Finally got in the bussman 125a fuse that busted on me (terminals were corroded). Hooked up to a second vehicle for about 10 min and she fired up. Here we're findings. Batteries after 1 month no running: One at 7V other at 10V. Run 5 min: 24.77 Immediate off: 23.70 30 sec off: 23.33 2 min off: 23.17 Ignition on: 22.99 Start: 16V and barely starts Running after 10min: 24.46V Turn off: 23.89 30 sec off: 23.50 Start: 17V I'm trying to get my hands on a battery tester before I order new ones. Can't tell if batteries are bad and not taking charge from alternator or batteries somewhat good and alternator is bad and also has a drain when off. Thoughts?
Also need to mention as I'm waiting on a tech manual, on the control panel near the odometer there is a red triangle/! This flashes after ignition is on for 8-9sec, when operating its off but comes back on at idle...
The easiest way to tell is to charge them up and see. That's the easiest way for me, you could swap batteries, or charge them up and test them. If they had any charge at all a month ago then those are two totally junk batteries.
With those numbers I would even bet with my own money (and I don't do that often) money the batteries are comprehensively fcuked ...............