I almost condemned a good alternator at the behest of a AutoZoo monkey trying to sell an alternator. It was the glow plugs. Be sure they are off. Don't guess or as s/u/me.

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85SD 240K & stopped counting. 84SD 180,000. Thinking of painting both.

Did you pull out the VR (Voltage Regulator) and visually look at it?
The Brushes could be worn down to the nubs.

I was having Alternator problems with the 240. Replaced the VR and still did not charge.
Removed the Alternator, and pulled the VR. The Slip Rings were deeply grooved,
so guess that was the reason for no charge.
VR was worn down to nothing, wonder it still sorta charged.

Pulled one off my parts car. PO (Girl) threw a rod from not checking the oil.
So figured must have work as it was a driver at the time.
Had good VR, but it didn`t work either.

Looked through my pile of spare ATL. and stuck on one from a 300D. Charges like crazy. something like 14.6V at idle.

Did you remove the Ground Strap between the Engine Adaptor plate and Body?
Look down below the Oil Filter housing and you will see it. Accessed from under the vehicle.
Remove it and clean off the contact areas. This can give you all kinds of problems if it isn`t grounded well.

I can understand not wanting to crawl under the car at 8DEG. It`s 14deg here now, and I don`t even want to go out side.


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

If it was tested in the car, then all the connections are suspect as well as the alternator. My '87 wagon suffered from poor charging for years, and finally got to the point that I had to fix it. The problem was the connector at the alternator: all the female connectors had grown weak over time, and weren't fully making contact with the male lugs on the alternator. I took apart the connector, and cleaned all the female connectors and gently closed them up a bit so they would take a firm bite, and the problem was solved.

Your car has, I think, a different connection method at the alternator, but you need to check that connection as well as all the battery posts and cables and the aforementioned ground strap cable.

I also agree with pulling the voltage regulator and checking that out as well as the slip rings (for grooving / wear).

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

I tried looking for the chassis ground when I was cleaning some of the grounds the first time but with your advice I think I will be able to find it.

Last few times I have started the car I have not heard the glow plugs click off. How do I make them click off on there own?

Thanks for the help guys, I really apriciate it.

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1984 300d 130k daily
1980 300sd 220k ($500 steal )
1999 land cruiser utility/off-road/tow vehicle
Formerly
Om617 swapped 1982 240d aka "rolling probable cause"
2006 v8 4runner
2009 WRX

I pulled the alternator a few days ago and managed to pull the voltage regulator. One of the ends was about 1.5 cm long and the other was only a few mm lol. I ordered a new voltage regulator and should be arriving shortly.

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1984 300d 130k daily
1980 300sd 220k ($500 steal )
1999 land cruiser utility/off-road/tow vehicle
Formerly
Om617 swapped 1982 240d aka "rolling probable cause"
2006 v8 4runner
2009 WRX

Voltage regulator replaced, I need to buy another multimeter to see if it is charging but it does appear to be. However heaven after running to for 10 mins at idle the elect rivals are still being wonky. Brights make the temp and fuel gauges spike, reverse and drive light up all the dash lights, ect.

I'm pretty sure this is due to a bad ground or perhaps a parcitic draw. Problem is I'm not sure where it would be. I clean off all the grounds in the engine department. I know there are some in the trunk but I feel like those would ground themselves somewhere towards the back rather than up front but idk.

Any thoughts? Any grounds I might be missing?

__________________
1984 300d 130k daily
1980 300sd 220k ($500 steal )
1999 land cruiser utility/off-road/tow vehicle
Formerly
Om617 swapped 1982 240d aka "rolling probable cause"
2006 v8 4runner
2009 WRX

Are you sure they are even coming on in the first place? Does the glow plug light on the dash come on?

- Peter.

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81 240D stick. 316000 miles at purchase. 342000 now
2000 GMC Sonoma
Formerly...
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles. Deceased Jan 08
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

Oh I'm sure they are coming on. If they were not it would not start. When I first bought it it was only running on 1 glowplug and it would take forever to get started.

So I picked up a new harbor freight multi-meter and tested the battery after driving it for about 7-8 minutes with the same electrical issues I have been having since before. Meter showed 11.6 v. Strange thing was that despite not having 12v it still started up. This leads me to belive the meter is inaccurate. I then bumped up the revs to 2k for about a minute with no real change in voltage.

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1984 300d 130k daily
1980 300sd 220k ($500 steal )
1999 land cruiser utility/off-road/tow vehicle
Formerly
Om617 swapped 1982 240d aka "rolling probable cause"
2006 v8 4runner
2009 WRX

I replaced the alternator and the same issues are still here, I'm not sure what else I can do

__________________
1984 300d 130k daily
1980 300sd 220k ($500 steal )
1999 land cruiser utility/off-road/tow vehicle
Formerly
Om617 swapped 1982 240d aka "rolling probable cause"
2006 v8 4runner
2009 WRX

It sounds like you have not yet located and cleaned the ground strap that is under driver's side bell housing to chassis.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Definitely clean both ends of the ground strap from the transmission bell housing to the chassis.

Worn voltage regulator brushes can cause your symptoms, as can a dying alternator, parasitic losses, dying battery, poor grounds, and poor battery terminal connections.

You've replaced the alternator, so scratch the first two things of the list.
You should have your battery tested, off the vehicle (free at Autozone), recheck an clean all connections from the battery to the alternator, starter and the aforementioned ground strap between the transmission and the chassis.

The alternator plug harness may have a poor intermittent connection, or one that becomes detached due to engine vibration.

Recently I diagnosed this fault on my 83 W126 300SD.
The alternator was replaced with a rebuilt Bosch unit 5 months ago (bad diodes on the old one) and a new Duralast Platinum H8-AGM battery 2 days ago (internal short on old 01/2012 Duralast Gold battery).
Two days ago, the alternator light came on during the commute to work.
The battery only read 12.25 V at idle, raising engine rpm made no difference.
Pressing and jiggling the triple spade alternator harness plug re-established charging voltage of 13.75 V. at the battery.
The two large spades on the connector are your positive power output, and the small spade is the exciter wire.

Adding an additional ground wire from the alternator body to the negative battery cable chassis grounding bolt can be of benefit.
I did that and also added another positive connection wire between the alternator and the power distribution block when I upgraded to an AL129X alternator on my 78 W116 300SD.

A description of the upgrade is at this link.
DIY - AL129X alternator in a 1978 W116 300SD

Best of luck in banishing your electrical gremlins.
I'm sure you will get it all sorted out.

__________________
79 300SD 'Stormcloud' new as of 10/22/2017
78 300SD 'Desert Rose' new as of 01/26/2014
83 300SD 'Rena 2.0' with engine from 82 300SD 'Rena' (SOLD & crushed 11-20-2017)

I cleaned the chassis ground strap about a month ago.

Thanks alec for the good advixe. I'll do try those over the next few days and then check back. Thanks

__________________
1984 300d 130k daily
1980 300sd 220k ($500 steal )
1999 land cruiser utility/off-road/tow vehicle
Formerly
Om617 swapped 1982 240d aka "rolling probable cause"
2006 v8 4runner
2009 WRX

unplug the vacuum pump in the trunk. if it is shorting or ? it will pull a lot of amps at funny times. ours shorted fully and the alternator couldn't keep up but everything seemed fine.