Hey team,

So I removed the starter on my 78 240D, replaced the solenoid with a Bosch (made in Germany) solenoid and reconnected everything. I go to put the battery in and nothing but sparks and the sound of the (solenoid/starter) making a whering sound and smoking. Everything in the car is off and for the life of me I can't think of anything I did wrong. Only modification I made was using a screw from Home Depot that I shortened. Any ideas? Any help would be great. All I know is that I have to make it to work Monday.

Just remembered, I removed the little screw that goes into the 10mm bolt and tried reconnecting the battery and it still sparks. So I'm guessing there is a short circuit somewhere else and that my solenoid is fine?

Thank you,

Garin

At risk of being obvious, are you sure you did not reverse the battery? Pos terminal to Neg cable.

grounding to frame somehow , somewhere, retrace your sets , look for shifted wires out of place... and as Rocky mentioned

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Ron
2015 Porsche Cayman - Elizabeth
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Why was the starter solenoid replaced?

Where are the sparks coming from? How about the smoke? Please be specific.

Is the replacement solenoid installed correct side up? One large terminal goes to the battery and the other to the starter motor. If these are reversed the solenoid might pull in but the starter motor shouldn't spin in it's own.

You might have the battery cable and starter wire touching at the starter.

Good question. It is seldom worth the effort to change just the solenoid. A rebuilt starter doesn't cost that much. If the problem is in the starter, replacing the solenoid doesn't help.

I would guess that in order to get those sparks when connecting battery means that the starter is likely powered. Which means that the solenoid contacts must be closed. Perhaps the internal linkage is stuck in closed position? Perhaps that caused original solenoid to fail?

You may have o remove and bench test.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Thanks for the replys guys. The unit was installed with the position in the same position as in the diagram by Graham. It actually might be the solenoid making the sound because the car doesn't try and turn over. The smoke appears to be coming from down by the starter although I didn't have enough time to look. The sparks are coming from the terminal when I try and connect it. I changed the solenoid only because the screw broke as pictured. Tried to make it a quick easy and low cost repair.

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Hard to tell from the picture but it appears the positive cable end is touching the screw terminals. The armature/commuter lead ( flat, braided copper cable from the solenoid to starter) looks kinda hokey also. I'd double check it.

Just went through this same thing with a M115. If there is contact between the battery feed and the armature/brushes/commuter lead, the starter will spin but the solenoid will not engage the drive gear.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Hmmmm I'll reconnect everything in case something is hokey before I pull the starter. Thanks mike.

Would I be able to bench test test the starter/solenoid using the power from the car battery with the starter disconnected from the vehicle?

Yup. With the starter out of the car, connect a ground/earth to an ear of the starter housing, disconnect the braided armature feed wire, touch a positive lead to solenoid screw. Solenoid should engage but not motor and the drive gear should extend.("click", "clunk" but no spin of motor).

Disconnect the positive feed. Keep the ground connected. Touch the positive lead to the braided wire. Motor should spin but the solenoid won't engage and the drive gear won't extend.

It's best to not use the positive cable end to do this test. Use a separate wire (10 Ga. or so). It's even better to use a battery charger (20 amp. setting) for safety reasons.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

The motor will kick if it isn't held securely. Best to clamp one ear in a bench vice while doing the testing.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

So it's definately the starter or solenoid. yhe battery would arc with everything reassembled. I disconnected the screw going into the solenoid and tried to reattach the battery and that is when either the solenoid or starter started wheeling up. Smoke came from underneath the starter and smells electrical, I guess. Once I removed the battery cable and starter ground cable from the solenoid the battery plugged in just fine.

Well, at least you know the starter bolts aren't frozen or stripped. Pain to have to pull it again but you learned a lesson. Always, always, ALWAYS double check your work.

The 10 minutes extra time you would have spent checking the starter would have saved you this trouble.

Take this advice from an old geezer mechanic. It is better to spend more time doing a job correctly than it is to do the same job in half the time, TWICE.

The best mechanic is a "lazy" mechanic. He only wants to do the job ONCE, no matter how much extra time it takes.

Double check your grounding strap while you have the starter out. Don't just assume you have the battery leads in the correct place.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Hey Mike. Didn't fix it. Just found out it still doesn't work is all. I've pulled this thing four times already in the last two days and am going to reinstall the old solenoid and see if the same problem occurs. I really wish it was just something I didn't connect right but I guess it won't be that easy.

Test it when you have it out BEFORE you change the solenoid.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

I just don't have a ground wire or a 10 gauge wire. Is this something I can pick up from an auto store? I put the old solenoid back in and put some power to it and it acted just like the other solenoid with and arcing battery, etc. I'll just test it in this same configuration just not attached to the car. I'm thinking maybe the ignition switch is not off all the way?