240D battery questions - PeachParts Mercedes-Benz Forum

mbzr4ever · #1 08-29-2014, 03:40 PM

This is for my w123, 1979 240D:

Had disconnected the red battery line for a few weeks, since I was anticipating doing some body work on it.

Hooked up the red line, started up, but then she idled rough, went a few yards, then she died.

Tried starting again, wants to turn over, but I think the battery is weak.

I understand these diesel batteries are different from regular car batteries.

Can I use this device to charge the battery? Battery Tender Plus

http://batterytender.com/includes/languages/english/resources/Product_Info_BT_Plus.pdf

Or should I try to jump it with my other cars?

My other alternative is to disconnect it and take it to the battery shop and have them charge it.

mbzr4ever · #2 08-29-2014, 04:38 PM

Don't think its the battery now tried jumping with truck, multi meter jumps around, 9-11 volts.
It starts but won't turn.

Gonna change the fuel filter next and check the gp relay.

Zacharias · #3 08-29-2014, 05:01 PM

Quote:

Originally Posted by mbzr4ever

It starts but won't turn.

Okay that's not too clear.

It turns over now, but won't start?

Or it starts then dies?

There is a difference.

Quote:

Originally Posted by mbzr4ever

Gonna change the fuel filter next and check the gp relay.

Eliminate one before going on to the other.

If you are cranking and the car is getting fuel, you should be able to smell it out the tailpipe (and you may see it coming out too).

Have you tried using the primer pump before and/or during the cranking?

mbzr4ever · #4 08-29-2014, 05:24 PM

Quote:

Originally Posted by Zacharias

Okay that's not too clear.

It turns over now, but won't start?

Or it starts then dies?

There is a difference.

Eliminate one before going on to the other.

If you are cranking and the car is getting fuel, you should be able to smell it out the tailpipe (and you may see it coming out too).

Have you tried using the primer pump before and/or during the cranking?

First it started, ran it a few yards, then it died.

It cranks, cranks but won't turn over.

So I just changed the fuel filter, the easy one. Yes, did the primer pump.
Same. Have a full tank of relatively new gas - within the past month.

Changed to a spare gp relay, but it sounded worse - slower crank. Doesn't make sense, does it?

The glow plugs are the pencil type, fairly new - less than 2 years old?

So I've got the battery in the other car - gonna take it down and have it checked.
The reason I'm in a hurry for this step is that there's the holiday weekend coming up, and I want to at least eliminate the battery as a potential issue.

leathermang · #5 08-29-2014, 04:58 PM

What " starts ' but does not ' run ' ?

mbzr4ever · #6 08-29-2014, 05:21 PM

Quote:

Originally Posted by leathermang

What " starts ' but does not ' run ' ?

Starts in that it cranks, but doesn't turn over.

Skippy · #7 08-29-2014, 05:25 PM

9-11 volts may not be enough. Charge and load test battery.

mbzr4ever · #8 08-29-2014, 05:30 PM

Quote:

Originally Posted by Skippy

9-11 volts may not be enough. Charge and load test battery.

Hope you are right - am leaving now to have it tested.

Skippy · #9 08-29-2014, 05:34 PM

I left my 300D sitting in a storage unit with the battery disconnected for a year once. My friend and I went to go pick it up in a Toyota MR2 which has a battery slightly larger than my motorcycle. We got it jumped, but it took a good thirty minutes of letting it charge before the battery was strong enough to to the job.

mbzr4ever · #10 08-29-2014, 06:22 PM

It's charging at the shop now for about an hour or two.
They said it was reading 12.2, and should be 12.7, and was about 5 years old.

Would a .5 charge make such a difference?

vstech · #11 08-30-2014, 02:40 AM

Quote:

Originally Posted by mbzr4ever

It's charging at the shop now for about an hour or two.
They said it was reading 12.2, and should be 12.7, and was about 5 years old.

Would a .5 charge make such a difference?

12.2 is a battery at 20% charge 12.76 is 100% charge...

I would get a bottle with clean fuel in it, and connect the lift pump and fuel return lines and see if it runs.
Both fuel filters need to be good for the car to run. Air filter needs to be good...

mbzr4ever · #12 08-30-2014, 02:47 AM

Quote:

Originally Posted by vstech

12.2 is a battery at 20% charge 12.76 is 100% charge...

Really?

Quote:

Originally Posted by vstech

I would get a bottle with clean fuel in it, and connect the lift pump and fuel return lines and see if it runs.
Both fuel filters need to be good for the car to run. Air filter needs to be good...

Great idea. Last fill up was about 3 weeks ago. Could have filled up on already "aglea-ed" diesel that was sitting - does that make sense?
Could I also add some additive - hate to throw out a whole tank of diesel @ $5.50 per gallon.

vstech · #13 08-29-2014, 06:24 PM

The battery may be weak but it has nothing to do with the car stalling. .. battery is irrelevant once the car starts.

mbzr4ever · #14 08-29-2014, 06:32 PM

Quote:

Originally Posted by vstech

The battery may be weak but it has nothing to do with the car stalling. .. battery is irrelevant once the car starts.

Yes, exactly, that's why I jumped to the fuel filter, gp relay....

But taking it to the shop at least eliminates it as an issue (I can start with a good battery) and I can move on to the next step?

Don't know, but all I know is that the 240D is sooo much easier to work on than the Ford or 300E!

mbzr4ever · #15 08-29-2014, 11:13 PM

So now the battery reads 12.63V.

Still cranks but won't turn over.

It's either a fuel problem (or compression), or the glow plugs, right?

I'm gonna test the plugs to see if they are ok.