W114 Questions/Problems

[Atzbenz]

Hi all,

I just purchased a 1974 280 w114, and have a problem with it that could probably be an easy fix (hopefully). here the story goes.


I just purchased a 1974 MB 280 (W114) and it is in great condition with 130,000 miles. I inspected the car, checked the oil, coolant and air filter and drove home. Now on my way home the car slowly lost power and eventually stalled. I figured either the battery or the alternator, so seeing as the battery was flat I took it in to trickle charge. However, after just 2 minutes it would show it was full so I concluded it was toast. Went to buy a brand new battery model (G4860) as specified by my mechanic. After a week of sitting, the car started like a dream with the new battery. No idle problems, blue or any smoke from the exhaust, and all seemed good. I let it warm for about 5 minutes and carefully drove to a gas station to check the tire pressure.

On my way back the car slowly died again and i pulled over. It would not restart, so i let it rest, and checked all the connections to battery, alternator, plugs. Then i tried it again and it would start very rough.. It fired but barely kept itself at high enough idle so i had to rev it manually to keep alive. I drove home like this (only 1.5km) and then parked and shut off. Now I will not restart as i am afraid i might do more damage. It does not seem to be the alternator, otherwise how did i manage to start it again? Please help, i love my car and im a poor student. thanks

Pics or ban rules are not neglected, so here is my beauty.

 

[Atzbenz]

just spend some time on here trying to find a similar problem and in thread:
http://forums.mercedesclub.org.uk/showthread.php?t=62713&highlight=w114&page=2

Post #15 mentions "Check the switch gear box near the Coil, these are prone to failing. The voltage drops suddenly which causes the car to stall. I always carry 2 in the boot, if my car suddenly cuts out this is my first point of call."

new questions, since my symptoms are very similar, where is the switch gear box located exactly?

 

[teddycatkin]

Looks a nice car ? Sounds very much like the coil to me as it gets hotter they warm up and start to malfunction ---(try a new one)

 

[74merc]

The 'switch gear box near the coil' sounds very like the relays, which are located on your driver side close the bulkhead.

 

[Atzbenz]

just got back from playing around with the car. Eventhough im pretty sure the alternator and battery are in good shape, she will start and die in about 10 seconds if that much...

Now i have discovered the my dash is making a slight buzzing noise as soon as the battery is connected. It will do the same noise without keys in the ignition and with or without lights on... Could there be a opening in the circuit or cause of some electrical leak? Why would it run perfectly for 220 minutes on a brand new battery? All fuses seem ok but perhaps i should eliminate a few to narrow it down... so confused...