What could a mechanic do to fry both an alternator and starter?

I have heard that a dead ground like this can change the crystal structure of the interface between electrical contacts due to heat, etc. I wonder if it is an intermittent grounding problem.

The problem only happens after the truck has been running for 10 minutes or so. It won’t start when shut off but if left overnight, it fires off without issue. One time I thought it was fixed and I was camping. I just let it sit and it fired right up but I am beginning to trust this truck less. Another thing is that I always park it where I can pop start it now.

Old cars are like girl friends. When you can’t trust them, you need a back up. Luck.

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If you have a high resistance ground between the engine and the chassis, that could cause this symptom. Sometimes that will also cause other weird symptoms b/c the ground current from the starter back to the battery will go another way, for example if 4WD, along the front axles. Check potential current paths like that; do you see anything unusual? Burn marks? Rubber parts melted or distorted? etc … You’d think you could just test it with an ohm meter, but it’s very difficult to measure the ultra-low resistances needed for the starter, since it uses 100+ amps. The most likely spots where that would occur is where a ground wire meets up with the chassis, like where the battery ground connects to the chassis. Or where the engine ground connects to the chassis. Might pay to just remove those connections, clean them to bare metal with wire-brush/sandpaper etc, then re-connect. Disconnect battery first of course.

I have this sort of problem with battery operated electrics all the time . Not a one of my flashlights works consistently, usually have to jiggle or knock them before they regain full brightness. Same w/audio connectors, like plugging earbuds into portable radios. All of them are very sensitive to whether the plug is twisted to the right orientation or not. I think evreyone has this problem. So common we don’t even think about. A recent tv program, science fiction, the character has a small pencil-shaped gadget he uses to open the door of his spaceship, doesn’t work, so he taps it a couple times, voila, it works … lol …

If you have a grounding problem it will show up when measuring the voltages at the starter during cranking, provided you probe between the starter terminal and starter case.

I checked the grounds and cleaned them, made sure they were tight, etc. I did have to end up replacing the starter as it appears that the solenoid on the starter was intermittent.

So far this appears to be working well. I did really tighten everything down as tight as I felt safe. I was worried about ripping the hot lead off the starter or stripping something if I went any tighter. I have a tendency to put a lot of muscle into things so might have been too cautious about breaking something.

This only happened when the engine had been running in the recent past and never after it had been sitting. AutoZone did say that a lot of parts have been coming back bad right out of the box in recent months. This seems to be a common issue through many industries with too few workers and supply chain issues…

Something electrical overheating? Coil?

Could something in the ignition switch be causing this? I did check voltage and it was over 12 V.

When it doesn’t start, what exactly happens? Nothing? Then it could be ignition switch or neutral safety switch, but I don’t know why they’d work when cold.

I’m not a mechanic. I’ve only had trouble with light switches and in both cases they seemed to work ok at start but then would heat up and fail. So I guess I’d try and see if you have access if it heats up some. Secondly, I don’t know if a bad switch would have caused the original alternator issue. Possible I suppose but I just don’t know. Gotta look at a wiring diagram. How expensive are they anyway?

Basically I had replaced the starter with a new one 3 years ago due to similar conditions (click but no cranking) and never had an issue until it went to the mechanic to have a new clutch set installed. Of course the starter must be removed before the transmission can be separated.

Anyway, upon pickup from the mechanic, I knew there was a problem as the charging light was on. I just took it back and left it. The alternator was smoked, a fuse was blown, and there was some mention of hard starting but it fired up for me at first.

Anyway, then the clicks and no starts happened. It would start when cold but not when hot. Replacement of the starter and solenoid on the firewall solved it, then it started again. 2x solenoids and 4x starters later it seems to be working but for HOW LONG? One of the starters was obviosly defective with apparent physical damage. I didn’t see this until it was nearly mounted but the positive lug was damaged. It seems that someone might have returned this one as the parts store indicated some normal packaging material wasn’t present.

It is starting for now but that was the case before. It seems getting this many bad starters in a row is not really a common probability.

The symptoms are always the same.

  1. Click and non-start or difficult start condition.
  2. This only happens when the truck has been run recently
  3. When it starts, the starter always cranks hard and strong. It isn’t like a sluggish dead battery. It is either ALL or NOTHING. The battery has been tested and looks good. Mechanics said all the lights are bright when the engine is off which is a good quick and dirty battery test.

All seems well for now though so we will see. I wouldn’t be worried except this is the 4th starter!

The truck was used quite a lot last weekend and never skipped a beat so I am hopeful this is solved for a while.

Something else came to mind if this problem returns. Someone mentioned a neutral safety switch. This is a manual so doesn’t have a neutral safety switch but does have a CLUTCH safety switch. I wonder if that could be the issue.

Keep in mind that this started right after the clutch and the two associated hydraulic cylinders were replaced. Do you think this might be the next thing to check if it happens again? I could probably just jumper the connection as a short term fix and for testing if this happens again. So far things have been good but I am reluctant to consider it completely fixed after all the nonsense I went through.

I had an intermittent no-crank problem w/my Corolla one time traced to an “iffy” clutch safety switch. Temporarily bypass isolated the problem.

Interesting… This all clicked for me when someone mentioned a neutral safety switch. Did you get random clicks like with a dead battery but when it decided to fire, it fired with great gusto like the battery was perfect?

I am going to figure out how to bypass this but leave it intact until it happens again. When it does I will bypass and see if that fixes it, then I will replace the switch. I feel like I have thrown some parts as this probably that probably weren’t required and still wonder about the odds of getting that many defective starters.

Yes, but usually just a click.

Sounds like this my next target if the problem returns…

As I recall the circuit design involving that part on my Corolla is weird. They changed the arrangement prior to my model year, then they changed it again the next year, so apparently they were trying to come up with a more robust method. If you post a schematic as it applies to your truck you might get some ideas here.

I will get on this in the next day or so. It appears I have several pins on the assembly so it isn’t just two pins to complete a circuit.

As a DIYer, I learned years ago to go back and check my recent work when something fails. There are coincidences but not as many as we think.

Testing the inputs and outputs of a remote mounted starter solenoid is basic electrical diagnostics, even an IT man should be capable of this.

When tested, the voltages were good at the firewall solenoid and the starter. Of course it was acting perfect when tested. I do think I will keep a multimeter in the truck in case this happens again though. It seems that this truck seems fixed for a while and then it acts up again. I am usually in a hurry and just roll start it when it does this. I had the time to mess with it one time while it was acting up but a big storm was incoming.