update on my 1987 300TD... - PeachParts Mercedes-Benz Forum

vstech · #1 11-04-2011, 10:41 PM

ok, lesson learned AGAIN

today after helping a guy with his SD, in my yard for him helping me in the yard, I worked on his car. got him a decent spare tire, and replaced his cobbled but locked up ignition setup... tinkering here and there, ended up his battery would not start the car... I recently ran over my shop charger, so I hooked up a set of jumper cables to my TD, and began charging up his battery so he could start... he turns on the glows, and his cabin light nearly turns off... WITH my cables on my car... obviously a bad battery, but he hits the key to try starting... not gonna happen. I disconnect, and get him a good battery, and he's on his way. I pack up and head out. it's around 8:00 by now, and I take his battery to the mcparts for a warranty tradein... got 50ish off the price of a new battery, and toss it in my hatch. heading home, the blower is on, and the headlights, and the radio, and I notice the ABS light comes on... and the radio starts resetting at random times... I'm thinking the mess with the rear wheel has something odd going on, speed sensor wire cooked or something... then I touch the brakes for something, and the radio blips. do it again, it does it again... I realize the battery voltage is low...

ARRRRGHHH!!!!! I fried my alt jumping his car!

sixto · #2 11-05-2011, 12:03 AM

Hopefully just the regulator.

Sixto
87 300D

retmil46 · #3 11-05-2011, 10:23 AM

Ahhh, the blessings of having a 2000 S-class 150 amp alternator in my 87 - high beams and fogs on, rear defroster on (and all the wires work), defrost on full heat on high, still cranking out better than 13.5 at idle.

vstech · #4 11-05-2011, 10:43 AM

yeah... try hooking a set of jumper cables to an SD with a bad battery, and have it crank... I bet your 150 amp alt crys for it's mama...

retmil46 · #5 11-05-2011, 11:38 AM

Quote:

Originally Posted by vstech

yeah... try hooking a set of jumper cables to an SD with a bad battery, and have it crank... I bet your 150 amp alt crys for it's mama...

I've no doubt of that. On the 05 Jeep diesel, it had an odd size Optima Red Top made to Chrysler specs - ie, dirt cheap. Not a year after buying it new, that Chrysler-speced Optima dropped a cell. That 160 amp alternator would squall like a stuck pig for 3 or 4 minutes, working it's butt off until it could jack the battery and electrical system back up over 14 volts. Put an $80 regular Group 34 Autocraft battery in it, and haven't had a problem since.

I've often wondered how many Jeep CRD owners replaced the decoupler pulley on their alternator, thinking it was bad because of the squalling noise it made on startup, when in reality it was that cheap-a$$ Mopar battery causing all the problems.

FCOL, even my old 87 Subaru, all of $12K brand new, had a voltmeter as standard equipment - and they couldn't be bothered to put one on a $40K MB?

bigblockchev · #6 11-05-2011, 11:41 AM

You get into trouble when you are trying to help someone or trying to save them money , and if you are in a hurry it is guaranteed disaster will follow shortly. Sorry to hear about it. Cheers Dan

vstech · #7 11-05-2011, 12:41 PM

meh, disaster is a tad harsh, I'm prepared for just about any outcome with a car by now... just annoying to have to deal with yet another issue with this car while I'm clearing my property...
I've got a new 140Amp alt I could put in there, or install a 100 amp I pulled from a 300E... not sure. either way, I've got a brand new battery in the back seat. I'll get home no issue.

sixto · #8 11-05-2011, 12:57 PM

Quote:

Originally Posted by retmil46

FCOL, even my old 87 Subaru, all of $12K brand new, had a voltmeter as standard equipment - and they couldn't be bothered to put one on a $40K MB?

The SRS light is a de facto voltmeter for cars with airbags.

For anyone who wants to upgrade a W124 alternator - Installed a 143A alternator in my W124 (86-95E-class) - with photos

Sixto
87 300D

scottmcphee · #9 11-05-2011, 06:37 PM

Anyone determined the voltage SRS / Airbag light comes on at as the battery slowly dies due to charging issue?

I noticed this was the first light to fault on as the battery was dying (regulator issue).

amosfella · #10 11-05-2011, 06:43 PM

I boosted a C95E cat tractor with my sdl with a 165 amp alternator I put in it to run my stereo... Alternator squealed like a little *****, but the big CAT started... lol

vstech · #11 11-05-2011, 09:32 PM

Quote:

Originally Posted by sixto

The SRS light is a de facto voltmeter for cars with airbags.

For anyone who wants to upgrade a W124 alternator - Installed a 143A alternator in my W124 (86-95E-class) - with photos

Sixto
87 300D

Quote:

Originally Posted by scottmcphee

Anyone determined the voltage SRS / Airbag light comes on at as the battery slowly dies due to charging issue?

I noticed this was the first light to fault on as the battery was dying (regulator issue).

My SRS light never lit up, but my antilock light did... about the same time I noticed the radio blipping on and off...

sixto · #12 11-05-2011, 09:59 PM

Off topic and barely relevant - I was 340 miles into a 360 mile trip in the 'burb 6.5T. Voltmeter was dropping from the typical 14V. 10 miles out it crossed 12V. 5 miles out it crossed 10V. Shortly after that it tried to put my face through the windshield when electronic O/D disengaged. Ha! I was expecting it from when the alternator failed a couple of years ago. I crept to my destination which is all you can do in third gear with a 3500 rpm redline. I understand the Stanadyne IP lift pump doesn't last when the electric pump doesn't help. Two strikes already. Turned out one of the batteries died. I disconnected the dead battery and had no problem getting home. I thought batteries only died overnight.

I'll ask Jeremy how to subvert the charge warning light to flash below a set system voltage.

Sixto
87 300D

bigblockchev · #13 11-05-2011, 11:01 PM

Also OT. I went for a 250 mile trip to load up my 86 Chev 3/4 T diesel 4x4 with several hundred pounds of apples. Truck started just fine in the morning, when we were loaded up at the orchard and went to leave there wasn't enough juice to light the red lights in the dash. Sure enough both batts were dead as doornails. We were traveling over some roughish roads which apparently shook something loose. As long as we kept it running we were fine. The only critical element was the fuel solenoid in the IP which needed juice to stay open. Cheers Dan

vstech · #14 11-05-2011, 11:18 PM

I understand a 9v battery tied to the pink wire can get you home when your batteries and the alt fail...

vstech · #15 11-07-2011, 10:22 AM

today the alt goes in... wish me luck! I tested the alt last night at the mcparts place, all good across the board. and WOW did it drop the tester's RPM when they did a load test!
I REALLY hate charging my battery each night... happy to get this installed today.