smoking wires

[maynarga]

my 240D turned over slow so I turned key off. It continued to try to start for up to a minute even with the key out. Then I smelled wire burning. I noticed the ground cable at the battery post smoking. Any ideas? /forums/images/graemlins/confused.gif

 

[KCinBr]

Sounds like possibly the starter solenoid is sticking. Causing the starter to continue running and this could cause the ground cable to get hot.

The starter draws a lot of amps but ususlly for a short period of time during startup.
soleniod would be a good place to start checking.

 

[BB_TX]

As KC said, it is probably the solenoid, which is basically a very heavy duty relay. When you turn the key, it energizes the solenoid coil which closes a set of heavy duty contacts to supply power to the starter. Sounds like the contacts are remaining closed even after you turn the key off. The solenoid could be sticking and remaining actuated even after power is removed, or it could be a bad key switch keeping power to it even after you turned the key off. I don't know anything about the 240D. If you can disconnect the solenoid from the starter, you can troubleshoot it easier.

 

[slowrev]

yep the starter solenoid is probably sticking. However the smoking terminal on the battery indicates a bad connection there. Clean the post and terminal.

Ben

 

[JayDavis]

I agree that you might also want to check the ground connections. They may be dirty/loose.

I got a story behind that advice.....A few months ago me and my dad tried to start my grandfather's tractor that had been sitting for months unused. The battery was bad so we hooked up the jumper cables. I started the tractor while my dad stood beside. When it cranked up, all the sudden he started yelling to kill it and ran and got a bottle of water that was in his truck and started pouring it in the engine compartment.

The ground connection to the engine was underneath the radiator and over the years grease, oil and who knows what else builtup under there. When I started the tractor, the stuff caught fire.

We cleaned the mess out but there was no easy way to get to the bolt to tighten the connection, so we just made up a new ground cable and used a much more accessable place to ground it. Why they picked that spot I'll never know.

 

[jimainiac]

We had the same thing happen with our lawn tractor, minus the smoking wire. My wife went to start it, and it started, but the starter just kept running. I was glad I happened to be there, 'cause she wouldn't have known what to do. I grabbed a wrench and undid a battery cable. It was the solenoid. It was unnerving, I never had that happen on a vehicle before.

 

[TOMLESCOEQUIP]

A low voltage condition will cause the condition you've described. I'd charge/replace the battery and clean or replace the cables or ends before replacing the solenoid or the starter. Even a new starter will act as you described if it encounters a low voltage situation.

 

[skipmarcy]

Besides an electrical malfunction with the solenoid, your problem could also be caused by the starter drive mechanically staying engaged in the flywheel. A weak or broken return spring on the solenoid(if it has one) or a poor engagement of the starter drive gear into the flywheel causing it to stick - worn nosecone bushing or armature shaft, loose starter bolts, loose flywheel, loose engine bolts etc. If you can't find anything wrong with the electrical system after doing some of the recommended procedures above, look closely at the mechanical aspects I mention.

 

[TractorGuy1]

I had the same thing happen on my Ford 1200. When I tried starting it one cold morning there was a puff of smoke that came from the wires around the starter. It ended up being a bad ground strap from the battery to the frame. I removed the ground strap and used the dremel to remove any paint and rust to bare metal. Applied some dielectic grease and re installed the cable. I also needed to replace the melted cable going to the started.
Have had no problem since. Good Luck

 

[Farmwithjunk]

Just an observation. From what I've seen, 90% of auto/truck/trailer/tractor related electrical troubles are resulting from ground problems.

 

[LeRoi]

Tom,
I agree with you on the bad battery/low voltage causing a starter to stay engaged.
I had this happen to me twice, first on a mercruiser stern drive on a cabin cruiser and later on my motorcycle, but when I list it as a probable cause for a starter problem. I get the blank look because I can't explain why it happens, just that it happens.
Leroy

 

[mopacman]

when a battery gets week it has a lower voltage. This makes the starter turn slower and the amp draw to go up. The high amperage burns the contacts in the solenoide till they burn together and stick. I hope this helps Larry

 

[LeRoi]

Well it makes sense except that all I had to do both times is change the battery to fix the problem. I didn't have to replace the starter or the solenoid.
Maybe the high amp draw combined with the low voltage keeps the solenoid engaged until you disconnect the battery or burn something up.
Leroy

 

[jgh]

20051128

Not trying to be a smarty-aleck, but I'd have an extinguisher made for grease fires around so you don't have to take the risk of putting water on such a fire and having another problem /forums/images/graemlins/blush.gif. Maybe some of the professional/volunteer professsional firemen on here could elaborate on this, as in what type fire extg to have, etc.

I just recall always hearing in science classes that putting plain water on a grease fire can make things much worse, not to mention shorting things out, etc.

Just 2 or 3¢ worth,

J

 

[MikeD74T]

Using water on oil/grease fires is acceptable unless you have a pool of liquid that is greater than 212 degrees, ie a pot of cooking oil on a stove. In that case the oil is usually much hotter 350-400 degrees. When hit with water, the water sinks then rapidly turns to steam violently displacing the flaming liquid. A grease (semi solid) or lube oil fire is put out by cooling the material below it's flash point eliminating the flammable vapors. This is readily done with water with less liklyhood of reflash and less contamination than dry chemical agents. you just have to have enough water, which is the limiting factor with water extinguishers. Then also there's the freezing problem. In annual training I use water to extinguish 16' square pits filled with 4" of fuel oil.