this is getting a bit out of hand...
 

guys,

this is getting out of hand. this is what electrical issue #3 for my 300SD? End of November I had an issue....tested it to death...determined aint nothing wrong...3 shops tested it (2 chain stores) one determined = bad alt. other said = it was fine. my mechanic said it was fine.

I pulled the car out of the garage this morning to give the guy working on the house some room to work...I get home to pull it back in...6-7 cranks and the battey is dead.

I've had no troubles ever since the 30th of last month and now what..what did i do? I havent dont anything with the electrical that could drain anything off....when the key was on..there is a 7amp drain on the battery...i was told this is about normal.

I need some help.

ALSO: When I did get it started, the engine had a low rumble..hard idle..then died. started it back up..was fine after a little touch of the pedal.

Much Appreciated,

Kris

How old is the battery? You could have a either a defective battery or your started has a small enough short in it that it sucks all the juice from the battery when you crank the engine.

battery is just now a year old. how can i test the starter for the short?

Draw on the battery (when off) is: .02A (tested in 10a position)

This sounds a lot like an issue I had a couple of years ago. After replacing the battery twice because they would randomly go dead even though the alternator was OK, I found an uninsulated electrical connector under the hood. There was a connector associated with the AC receiver that was more or less suspended in a wire. Apparently it would randomly short out to the body and kill the battery. This went on for months before I found the problem.

where is this wire that u are taking about...specifically..right now i am cleaning my dist. block's wires....

On my W123 it was in a wire connected to a pressure switch on the AC receiver, behind the right headlight. There is an electrical (push on type) connector in the wire a couple of inches from the receiver.

i seem to have miss noticeing this purple wire on the dist. block. which screw does it go to?

Wires:

2 sets of red wires (2 connectors - 2 wire in each)
1 thick white wire (1 thick wire)
1 thin white wire (1 wire in 1 connector)
1 thin blue wire (2 wires in 1 connector)

1 purple wire (2wires to connector)

i have bad luck it seems

UPDATE: It goes to the screw closest to the cabin..pics are a good thing..managed to find one of that side of teh engine.



DIST. BLOCK BACK TOGETHER.

I am going to look around my engine for that wire you mentioned, craig, but i dont think my AC components are on the right side of the car....mine are on the left..ill check out those connectors thou...

thanks

Have the battery load tested(not with the tester the Autozone uses). I had the same problem with a 82SD and it was the less than 1 y/o Delco battery. It would start fine for weeks then it wouldn't.:eek:

battery was just load tested 2 weeks ago...it was fine...

I took the car up on the highway for 30min...70mph...didnt have anything running..no stereo..no subs...got home...turned it off...sat for bout 2minutes..tried to restart it and it woudlnt even start...the engine was just under 80C...when it was trying to crankover..the TACH was jumping up to 3000rpms and down and up and down as it was cranking.

also volt. regulator was replaced 1 year ago, as was the battery.

I am thinking that its the alternator...it did this 2 weeks ago. Nothing has changed (3rd brake lights added in rear fog light holes but that isnt going to affect this)

i think its intermittently failing. sometimes it will churn out power sometimes.


AL129X = $160.

Thoughts?

Sounds likely...I had a flakey regulator that worked 90% of the time, it discharged the dattery stone cold dead 5 times over night....and once shot up to 17.8V running...smoked the Tach..stereo..half the lights in it...I now run a permanently mounted voltmeter....

Alternators can be intermittant too....work fine when tested and fail 5 minutes later. Sucks to spend the money on a maybe.....but killing batteries isn't cheap either. And for the record...5 full discharges on my old one year old battery wiped it out......

Luckily the batteries have all died within the free replacement timeframe. I've been tested the voltage at the battery wit the car running...revved it up a bit...i've never had it go anything like 17.8v...plus the fact that the regulator is only a year old..I am lead to suspect the alternator. I know its a maybe but, there are lot of positives it it comes out to be true. The negative..well ill have another altnernator. dont quite know what can be done with it but hey it can be added to my parts collection.

Thanks for the help doc,

Im taking the car in monday to have it looked at and an AL129X (115a) alternator fitted to it. Im not sure if my mechanic has ever done this before, if he hasnt is there anything i should tell him to look out for, problems in the install?

--Kris

Do a search using AL129X......there is a good size thread that tells you in explicit detail what you need....to fit that in any older benz....rather than rely on memory where I might get a detail wrong. Never mind..here is the thread.. http://www.peachparts.com/shopforum/showthread.php?t=93569&highlight=AL129X

Yep Kris, the AL129X will fit on your car but its not just a direct drop in and go...you have to sorta jimmy it in there.

No extra parts or anything are required...its just tricky to get it in there and everything hooked up. The case on the bigger alt touches in a spot so you loose some of your range of adjustment. Make sure you have a set of pretty new belts on hand if you havent' replaced them recently or else you might not get it to work.

Its a nice upgrade...some wiring will have to be done as well but its nothing more than running a bigger lead to the distribution block and then putting a ring terminal on the end.

Make sure you get the field wire hooked to the right spot :)

I am going in monday to see if my mech can do for me as well as take a look at my turbo. It seems to be throwing oil into the air filter as the filter looks like someone got creative in art class with the black paint. Also I am getting a modified air cleaner bracket. My uncle is going to reinforce it with some steel.

The oil is from the CCV oil return system...

If you seal it up with silicone (inside the filter) you won't have any problems...saved my filter :)