I'm posting this from my phone and i'm a bit frazzled so please forgive any typos.
I got this 86 300sdl with 67k miles several months ago and no probelms. It.s my first MB and first diesel. Today after work, My battery was dead so I got a jump start. It seemed to be running ok but then when I put it in gear it started "surging". Now, even turning on the headlights will cause the rpms to blip briefly. I got the car a few miles to my friends place in uptown Dallas but it does that surging and the lights will flicker.
I am kinda paranoid of all kinds of things? Is it just my battery? Maybe alternator, vacuum line somewhere? I had the odo and clock fixed yesterday. Could that have something to do with it? I was thinking of just making sure my battery is good first. Anybody have any other ideas of these symptoms.
Man I'm bummed.

First, figure out why your battery went dead. Is it a bad battery or a short in the system? I'm thinking a dead short somewhere could be putting a huge load on the alternator, causing the engine to surge.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

A brief tutorial on the car's engine controls:

The '86 300SDL needs NO electricity to run, at all. However the idle is controlled electronically, without electricity it will idle slower.

So, it is possible that low voltage is causing it to not idle properly. Charge the battery completely, and check that it is charging.

__________________

Gone to the dark side

- Jeff

need to get a DVOM and make sure the car is charging.

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91 350SD
14 F150 Eco
19 Fusion Hybrid
11 GT500

plan in your route to hit Autozone or Pep boys or Advanced Auto parts. They can check both battery and alternator for you.

At night your alternator has a huge load on it if the battery is dead or a cable not connected well or something. That forces the alternator to power everything and its not up to snuff for that job.

turn off all electrical that you can no heater fan, no radio etc.

__________________
"Know other lessons I need to learn? TELL me. Tired of learning'em the hard way".

Glow Plug Wait: [i} Time of silence in homage Rudolph Diesel. Longer you own a diesel. more honor you give". [/i]

Life; SNAFU Situation Normal All Fouled Up, & FUBAR: Fouled Up Beyond All Repair

-Now: Snafued Jeep TJ w/OM617 2Be daily driver & building SS M1079 w/Ambo boxed /live in Adv. Truck, Diesel KLR conversion
-Sold 62 UNIMOG Camper w/617 Turbo, 85 300SD

Yeah I really hope it's just the battery. My friend doesn't have a battery charger here and I think I will tackle this in the morning.

Hell I don;t even know how to take the battery out. It looks like that tank may need to be removed?

It's just wierd, even when running at low revs (1500 or so) it would still be cutting out or "surging".

With lights on or w lights off?

does it surge with ALL ELECTRICAL off?

__________________
"Know other lessons I need to learn? TELL me. Tired of learning'em the hard way".

Glow Plug Wait: [i} Time of silence in homage Rudolph Diesel. Longer you own a diesel. more honor you give". [/i]

Life; SNAFU Situation Normal All Fouled Up, & FUBAR: Fouled Up Beyond All Repair

-Now: Snafued Jeep TJ w/OM617 2Be daily driver & building SS M1079 w/Ambo boxed /live in Adv. Truck, Diesel KLR conversion
-Sold 62 UNIMOG Camper w/617 Turbo, 85 300SD

on rare occasion I have heard of alternators that are sticking to the point that they are occasionaly nearly locking up and putting huge strain on the engine whose belt is trying to turn the dragging alternator.

That could be another test. With a good battery . pull the alternator belt. start car with no alternator.... see if parked surge goes away.

__________________
"Know other lessons I need to learn? TELL me. Tired of learning'em the hard way".

Glow Plug Wait: [i} Time of silence in homage Rudolph Diesel. Longer you own a diesel. more honor you give". [/i]

Life; SNAFU Situation Normal All Fouled Up, & FUBAR: Fouled Up Beyond All Repair

-Now: Snafued Jeep TJ w/OM617 2Be daily driver & building SS M1079 w/Ambo boxed /live in Adv. Truck, Diesel KLR conversion
-Sold 62 UNIMOG Camper w/617 Turbo, 85 300SD

But don't run it more than a minute or two without a belt!! Or it will overheat and crack that head!

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

So basically I meant to say that the battery was measuring 12 V and was probably never dead in the first place. when the guy placed the jumper cables on just right he was able to squeez that nut to the terminal and that's how I got the car started last night.

I feel like a huge moron.

I found that one of the wires on the positive terminal was loose (the smaller one going towards the front of the car).

I went ahead and took the battery to O'Reilly's even though I kinda knew that wasn;t the problem. Of course they said it was bad and I bought a new one. It probably had quite a bit of life left in it but I don't know when the P.O. installed it and it's kind of good that I replaced it anyway I guess.

So I get back and install it and tighten the terminals on the posts good and tight and still nothing. Not a click, not a sound at all.

Then I finally found that the other nut on the outside of the post was loose. Bingo.

I can't believe I didn't see that or check that before. Oh well. I'm happy again. and I had to apologize to my car for thinking all these bad things about her.