negative battery cable hot/car not starting?

Hello, the battery cables need to be tight and secure. If the cable is getting hot and smoking, there is too much resistance, most likely between the battery post and negative cable itself. The proper way to check the connection is to check for voltage drop from the negative battery post to the engine block with the key on, and engine running for a minute if it will start, if not, then just key On, and turn the headlights on as well to load the electrical system some. set your multimeter to DC volts and make sure the meter lead is on the battery post, not the cable, you need to see the voltage drop that's occurring between the battery post and cable and put the other meter lead touching the engine block. So, it's a ground side voltage drop test. If the cable end is broken, it needs to be replaced. A bad ground like that can damage other components. The starter is clicking because there isn't enough current flow due to the high resistance at the broken negative cable end. Can you take a picture of the negative cable so we can see what the broken end looks like?
The starter motor pulls hundreds of amps, that's why the cable is getting hot.

https://www.2carpros.com/articles/how-to-use-a-voltmeter

You want the voltage drop from battery negative to the engine block to be close to 0volts, Check from battery negative to the vehicles body(chassis) as well.
You can do the same test on the positive side as well, from battery + to the positive wire on the Starter motor. Point to point testing, should read close to 0volts as well.

Removed the cable and ordered another one. Removed the belt in case sometimes it seized but motor only turns about 2 inches back or forth. Hopefully didn't seize which would make no sense, as car was only driven a minute and has oil and coolant and just died while driving cause of the issue. I have a new battery as well. Even with the wire removed now i connected a jump box and it also sparks more than it should when i attach the ground to body.

Well, wait until you get the new cable on there before you go hooking up any jump boxes or anything, Try turning the engine over by hand if you suspect a mechanical issue. Just use a socket on the crankshaft pulley and a large bar, you should be able to turn it over. You'll be pushing against the compression of the cylinders, so it will be a little tough, but it should rotate, you can also pull the spark plugs and then it will turn over by hand really easy,

I didn't push too hard while turning but ill remove plugs and try as well.

Leave that jumper box off until you get the battery cables all sorted out. With the negative cable off you don't have a complete circuit right now.

Plugs out, same results. Ugh. I am removing the starter to see if it will move. Until i get the cable.

You're not able to turn the engine over by hand?

No, only 2 -4 inches only then i feel resistance.

That's not good, are you thinking the starter gear may be engaged into the flex plate? And I assume it didn't start at all after the new battery was installed and the cable was overheating?

No didn't start at all since it shut off with old or new battery.

Something electric is also happening, hoping the starter is jammed out yes.

You might try taking off the main drive belt as well and see if it will turn over, just to be sure it's not a seized-up alternator or ac compressor. Thats easier than pulling the starter first, just to verify it's not something else. I'm wondering if this has some sort of vacuum pump or high-pressure fuel pump that's driven by a camshaft, when those seize up, it can cause issues like this as well, I'm just looking at some diagrams of the engine here. Do you see steel fuel lines going to the fuel injectors?

I already removed the belt before turning it. Well, to i know it has a hpfp, not sure about vac pump. Actually, it did have codes for the fuel system it would run and shuts off. Hmm, that's interesting. I'll look at steel lines.

Fuel pump.

The problem with the high-pressure fuel pump is its mechanically driven by the cam, and when they fail, there ends up being metal shavings stuck in the fuel rail and into the fuel injectors. It can be a real mess. You have to release the high-pressure fuel in the rail before taking any of the steel lines apart, and they are usually a one-time use. The high-pressure pump can run 500 to 2000 psi, so you can't just unbolt the lines to it. I would hook up a scan tool and see what the fuel rail pressure sensor is reading for pressure once you get the battery cable fixed. Do you remember what the codes were?

P2015, p130, p135, but i saw something about fuel codes. I removed these pumps before, so I am familiar with them and with the cam lobe inside them. Think i should try and release it, and see?

Well it's difficult to say what happened at this point, you did have it running, and the HP pump has to be reinstalled at a certain position and service info here at a quick run through is stating the crank needs to be rotated until the cam follower is at its lowest point, And then install the cam follower into the vacuum pump and then the high pressure pump into the vacuum pump. So, this is no easy task to take apart, just to verify the engine will rotate.
I'd say pulling the starter is the easier thing to do, I take it this was an auction vehicle.
This looks like a serious job to replace this pump, some of this service info is talking about removing and installing a camshaft adjustment valve, there's pages here for just the HP pump. This requires special tools listed here as well.
I do hope you find the starter jammed up into the flex plate, when you get the battery cable hooked up, go in and check the live engine data PIDs and see if there's any fuel pressure reading. I'm trying to find some info on the starter location, there's quite a few design variations listed. ( 2.0L FSI manual, TFSI manual, TDI manual trans,) Those are the 2.0liter listings.

The P0130 and P0135 are the B1S1 oxygen sensor (circuit) and (heater) faults, the other code is the intake manifold runner position circuit perform.

Looks like the Starter is under the air filter housing.

This is a 2.0 TSI, manual transmission, yes auction car but ran so smooth when i started it. I am familiar with them and know how they should sound, otherwise I would not have bought it. Weird they make it so complicated to replace the hpfp. I replaced many of them on Minis and BMWs as well as VWs. Didn't have to do any adjustments at all.

Yes, i see the starter. I'll see where the bottom bolt is.

Well, the HP pump needs to have the cam follower at its lowest point, so when you bolt down the pump, there's no pressure being put on it, and then working the bolts down each a little at a time, which is how most of these pumps are installed. It's just odd that there's a vacuum pump that seems to be driven off the same part of the cam, I'll post this section on the vacuum pump really quick. Below is the info on reinstalling the HP pump.

Yes, that's how i usually install them, make sure it's all in and slowly screw in the bolts one at a time from side to side until it's in.

If it ran that good, I don't think anything crazy happened on the drive home with it on the trailer. But check the starter first, no sense in pulling the entire thing apart to find it's got a broken flex plate or starter issue.

Just wait to try starting it again until you get the cable and battery hooked up correctly.

No, my tow truck driver is a friend of mine. He knows a bit about cars so i always tell him to drive them for a minute to make sure it's okay. He drove it after he jumped it just to make sure the shifting is fine, only few hundred feet and he said it was so smooth and just shut off.

oh okay, if you look back under mode 6 data, there may still be some recorded faults in there. I use mode 6 data sometimes when a vehicle has an issue but is not setting a code. There is always a fault in there for something. It's just data you have to search through. It will show different ID #s and Test IDs, but you should always record any fault codes before erasing them. Or take a screenshot with your scan tool so you have a record of the fault. I assume it stalled out due to that faulty battery and cable, there are just so many components on these engines, let us know how things turn out by trying to rotate the engine. If you have the starter out already. Being a manual transmission, you'll need it to be in Neutral when trying to turn it over by hand, just chock the wheels. I didn't see it was a manual trans until after my first few posts.

Installed the used cable, went to try it, I got a different noise this time, it's a push button start, so tried it3 times, stopping between each turn and got a lot of smoke coming from around the starter so I stopped. Nothing from the battery cable this time. But I didn't do it long enough for the starter to develop this heat already, very strange. I had my share of bad starters, and they usually have different symptoms or noises, sometimes no noise at all, sometimes a click. When I tried here the noise was weird, grind noise maybe...I removed the + cable coming from battery to starter, and the negative cable from the ground to starter and the harness as well as top bolt, will remove the bottom bolt soon to see what is going on. Is it possible the starter is bad, or the engine just seized and therefore the starter isn't able to turn it and creates this much smoke?

Looks like the starter is also not working if how I am testing it is correct. If i pull the gear it comes out by hand. The engine is still not turning by hand. Is it possible even if gear is in neutral that transmission maybe has something preventing it from separating? Driver said car shut off as soon as he changed into 3rd gear at low speeds.

We are getting very close to a seized motor, which had oil, and was not being driven fast and with no symptoms. I still don't believe it. From a battery issue to a starter not sure what else.

Unless I am not putting enough force on the ratchet to turn the motor, which i doubt, as i turned by hand many motors in my life time. I think if i do any stronger it will either get loose or break, not sure.

In Neutral you should have no issue turning it over by hand, can you see up into the Clutch pressure plate with the starter out? And what if you have someone push the clutch in, can you turn it over by hand then? Something sounds fishy here. If you have someone push the clutch in, you should be able to see the pressure plate move somewhat, I'm not sure how much clearance there is to see with the starter out, but it does seem very unlikely to have a bad starter, and seized engine at the same time. Even with the plugs out. You can drain the oil and cut the oil filter in half to check for any metal particles. You can also pull the valve cover and see if a cam bearing seized up, Ill look through service info some more. I know this engine has a turbo and a lot of components on the top of the engine, or how easy it would be to pull the valve cover. But don't break the crank bolt off trying to force it over. If it's something on the top end keeping the timing belt/chain from rotating, the head can be replaced. But drilling out a crank shaft bolt is a real pain.
What's the VIN on this, so I can look it up by that?

#27 in the first diagram is the Vacuum pump, and the 2nd and 3rd the HP fuel pump. So, it could be either of these seized up, or a cam bearing. So, I wouldn't throw in the towel yet, we just need to figure out what happened.
Do they give you any idea of the condition of the engine at the auction, or is it pretty much take it as is? It seems very odd it would start and run, then whatever happened. The seller must have seen something or known something was up. The whole situation seems strange.

3VW5A7AJ9CM416372. Thanks all for the help. I can see part of the clutch yes, so try to turn it with a screwdriver at the flywheel teeth you mean? This is a big auction for CarMax and they don't spend time trying to figure out why a car will not start, they just announce an engine or a transmission when needed. If the car won't start that's enough for them. The car was dead as many usually are, not strange at all. But i always jump them. When i did it sounded like it was fuel starving a bit then smoothed out, and i mean smooth, no funny noises. Plus, whatever codes it had were mostly gone or all over the place but one was pointing towards a fuel issue, and then o2 sensors, nothing else that tells me it was major. Revved up the engine several times and it was smooth, has oil and coolant. No funny oil color.
My driver went to get it and he jumped it drove it out the gate and shifted it till he got to 3rd and then it died. He said it still had some lights with ignition on but would not make a noise as to crank. Ya whole thing is weird but i doubt she would seize just from a 1-minute drive when it was driven around before in order to park it where it was at the auction. Unless my luck is really bad. One of the codes was for the intake runner, plus the p130 and 135, but it is possible these were not all that are related.

Moved it by a screw driver and it moved same amount that the engine did, couple of inches or so. I actually hear a bump stop around the vac pump whenever the engine stops. Something prevents it from moving either like u said a frozen component or something inside the head. Ugh. I hate these vve covers and their design but i did remove them before including the vac pump and fuel pump. Am just afraid removing them and not finding anything and trying to turn the motor that i mess with timing of the cam, if i only removed the vac and fuel pumps.

Can i mark the location of cam from inside the cam lobe follower and try turning the engine after removing the pumps and if it does or doesn't take it back where it was? We only talking about couple of inches of movement.

Let me check service info on that, I believe it said to have the lobe that drives the pump at its lowest point, which in your case you can't do right now. But let me look through some Info, on it again. To me it looks like either the vacuum pump or HP fuel pump being seized up is going to cause the same effect. I don't work on VW, but I'll see what it says about replacing either of those pumps, they do list 2 different 2.0L Turbo versions here though, and I'm not sure what the difference is. If you want, you can leave the VIN it might make finding the correct info easier.
They have a 2012 VW Jetta GLI (162) 2.0L Turbo (CCTA) or the (CBFA) and those are the differences I'm not sure on, and that vacuum pump is for the brake booster.

3VW5A7AJ9CM416372

Thanks

Okay, so diagrams 1-6 are for the HP fuel pump and 7-9 are for the vacuum pump, now obviously the only issue you will have here is the high-pressure fuel, if any in the rail. Since you can't pull the low-pressure feed pumps fuse and run the vehicle out of fuel. I would hook up a scan tool and see if you can check for a fuel rail pressure data PID to verify the pressure is not still high.