87' 300 TD won't start

[show off]

I have a 1987 300TD wagon. The battery was completely dead and autozone checked it out and said I needed a new one. Got the new battery and dropped it in. When I connected the negative after the positive the horn started honking. I then went and stuck the key in the door and moved it until it stopped honking. I tried to start it and got nothing. The wagon has been sitting for a little bit so I let the glow plug light come on and go off a few times before i tried to turn it over. I left it for about 3 hours and when I came back and tired to unlock the door the horn started honking again. I jumped in and put the key in the ignition to hopefully shut the horn off. When I put the key in the ignition it turned it all the way and got the motor to turn over really slowly. I probably got it to turn over three times and then i was back to just nothing. I could not get the horn to stop honking with out the key in the run position so I just un hooked the battery. I am a deffinate noob to mercedes and diesel cars and was hoping someone could give me some advice to get this thing runnin. I imagine it is something to do with the security system but I have no clue.

[show off]

ttt

[dlssmith]

You might have an electrical short in the leads to the starter. Or the starter itself might be bad. Does it turn over at all when you turn the key?

[show off]

well it did the second time i tried to start it after waiting a while but it was real slow. Are there any security issues that i could run into when changing a battery?

[compress ignite]

If the alarm system is aftermarket the fun has yet to begin!
If it's M.B. and someone has messed with it you're still in for a version of the Marx Brothers automotive experience.


Look under the hood , there may be an alarm horn mounted on one of the wheel
wells.(kinda looks like a "BullHorn") detach the wires leading to it.[at least until
you find out what's wrong with it.]

Unless you've got the HooDoo Hex on your electrical system , the starter's
trying to go to that geat Bosch recycling facility in the sky.(Assuming the
connections and cabling to the starter are in good order)

Try putting a "Jump Start" on the system with the new battery fully charged.
Positive cable on the battery(s) positive posts...Negative cable on the recipient's engine block and then to the donor's engine block.
If you can reach the "Bendix" on the starter (looks like a small cylinder on top
of the starter) tap on it gently with a small hammer whilst someone else works
the key.

Observe the MOST stringent safety precautions when attempting the last suggestion!

[dlssmith]

Unless you were sold a battery too small, the engine should really crank quite fast with a new one if the starter is not fried. But the engine won't fire very easily if the glow plugs aren't working. No matter what the outside temp, this engine needs operating glow plugs.