I go to crank it and I hear electrical snapping and different solenoids clicking/clunking. I replaced the ignition switch and everything seemed fine for a while, but the gremlin is back. At first I thought perhaps it was a short to ground, but then that didn’t make sense as to why it would engage solenoids. What are the odds it’s faulty solenoids? Faulty logic controller? Faulty logic in the human? Something else I’m not thinking about at all?
First i would comfirm battery voltage both under load(cranking) and no load at the battery terminals and at the starter pole. Then i woukd bridge across the excite terminal on starter. This will rule out or confirm condition of starter motor, ing switch, solenoid and safety interlocks. If you report your results, then we will help with the next steps.
Look for chewed wires and such.
Update: Filthy contacts at the ignition switch caused intermittent contact with accessory solenoid. Solved. Still getting odd snapping at the park and neutral safety relays on crank. Unplugged the brain and still had snapping. Neutral safety is clicking as I adjust the reverser lever out of neutral. Shorting the starter cranks the engine.
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Got power at 26/22a on the pigtail Since the park relay and the NS relay seem identical, I tried swapping harnesses. Same thing. The relays are cheap, but I’m wondering if it’s failing harnesses. The wires all look ok
Assuming the NS relay and the test relay are good, the issue could be a poor bulkhead terminal connection on 23 WHT. 23 WHT energizes the start relay.
Took forever, but finally had a chance to get at the starter. Key on, jumped posts, no crank, but relays clicking. Does this indicate bad starter?
Most likely Yes but could be other things. So by jumping from the main big post from battery wire on starter to small exciter terminal it bypasses the ignition, interlocks, relays ect. So just to confirm it made a big “cluck” but the starter did not rotate? This should be the same “clunk” that you get when turning key key to start. If so it will most likely be starter motor faulty but could also be voltage drop or bad battery or bad earth.
Yep. Same “clunk” but no crank, but then other clicks type noises coming from the cab. Le sigh. I suppose the only real way to eliminate the starter is to take it out and bench test it.
Give the starter a tap with a small hammer while cranking. If it starts to crank its your starter faulty.
Spent the better part of the morning checking grounds, cleaning terminal posts etc. All critical electrical components in the dash check out with continuity to ground. Got power to the starter solenoid (12.2v). Got power to the starter (12.2v). Jumping battery post to little post on the starter solenoid creates big spark, clicking and klunk in the cab, no cranking. Jumping battery post to sender on the starter creates a small-to-medium spark, clicking and klunk in the cab, no cranking.
Keep in mind just because you show power, doesn’t mean you have clean power. For example, on my 555E I had no issues starting the machine in the summer and my voltages always showed great. However when it dropped below 40-45 degrees, more times than not, I would need a battery pack or jumper cables to get it started. My cables were not severely corroded, however they were bad enough that they didn’t allow enough amperage to flow through to make it start. Just a thought.
I’m not sure why I never think to include video. Trying to short the starter relay or the starter directly creates the same snapping, no cranking. The little strap that goes from the starter solenoid to the starter body - is that a ground or is it supposed to carry 12v positive? Here’s the video
All good mate. So power comes from positive battery through the heavy wire to the start solenoid. When you turn key, the solenoid is energised. This is basically an electromagnet that pulls the starter (bendix) drive into the flywheel and also makes a electrical contact inside the solenoid. The power then flows through the solenoid and out of the second large terminal, through the braded wire and puts power to the starter motor itself. Inside the starter motor there is brushs that power the armature through the commutator. The motor then turns the flywheel. All power returned to earth through the body of the starter to the neg battery terminal. Long story short, sound like starter is buggered. Tapping it on side with a hammer may give you another start as the brushs may loosen and make contact.
Sounds like your solenoid contacts are pitted. Most times, you can take that cap off and either flip the rotary plate or clean it up.
Pretty pitted. Cleaned it up, did what I could, at least I heard stuttering and clicking at the starter. Got a new starter on order.
Whoooof. Bout as bad as I’ve ever seen.
I never understand why people just don't do a few simple voltage drop checks and then you would know where your problem is. Four measurements and you would exactly where and what the issue is. Measuring voltage is really not checking anything. Voltage across an open circuit will be equal to the applied voltage. You need to measure the circuit when it is in operation to get a valid diagnosis. This is what a voltage drop is doing. Google voltage drop testing on starting/charging systems. Lots of good YouTube videos explaining it.
People that come to this forum generally have no knowledge of how to do this and don't realize it's something they can look up.
I often have to remember, what seems like basic first step to me, may most likely be a major education for a majority. lifetime of spinning spanners and hitting sh-t with hammers.
Me. I’m that guy. I’m here ‘cause I’m ignant. I understand what a voltage drop is (because I understand English and context clues) but I don’t know what it would tell me.
Update: original starter replaced (9000 hours, 36 years). Purrs like a kitten.