Mercedes-Benz Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter #1
Hi, any suggestions would be greatly appreciated. My '80 240D is hard to start in the mornings, and often during the day if let to sit for more than 4 hrs. I've have to had jumps almost every day for the last 3wks, I've bought a 650amp rechargable jumppack, and a 2/10/50v battery charger and engine starter. Even with the 50v engine starter hooked up, it still takes about 20min to start. At first It'l be "rrrr" (barely turning over), and maybe every five min turn over more and more, til finally the engine turns over fast enough to start (I presume.) The battery reads 12+ v at rest, two glow plugs that tested faulty were replaced a month ago (in prep for winter), the other two read less than 0.8 on my multimeter. (the ones I replaces read more than 1). I'm stumped. I did just order two more glow plugs (btw I have the pencil type, and they are hooked up correctly, from what diagrams I've seen.) so: is there a way to "blow" or ruin glow plugs quickly, and how is it possible to have a full charge and still have the engine sound like it's got a dead battery when starting (until some time has elapsed, and then it's strong and starts like a champ.) Thanks for any help. PS. could the starter solenoid be at fault or the voltage requlator? I do have a engine heater, I have it plugged into a timer, so starts heating the car an hour before I leave for work. Is an hour not enough time? It has been freezing lately. Thanks,
Matthew
 

·
Registered
Joined
·
11 Posts
Discussion Starter #2
I should also reiterate: during the day, after the cars been driven, itl start easier. But it's that morning start, and after I've been at work (8 hrs later) when i go out to start it and have to jump it or use the jumppack. I've been late to work most days, as even though I go out an hour and a half before work, it takes most of that time to sit there hooked up to a source of electricity to get it goin. And one more thing, the gauges jump from correct display to incorrect sometimes when the car is running (idle or driving). I mean, the fuel, temp, and oil pressure gauges jump sometimes. Hope this is enough info to start a discussion.
 

·
Registered
Joined
·
11 Posts
Discussion Starter #3
And finally: if I push on the gas pedal when starting, that seems to make it not start as often. After it starts, then I do put a lil pressure on the gas pedal for a moment. But If I try to start the car with the gas pedal pressed all the way down (as has been suggested here somewhere), that seems to hinder the starting. I do have the idle knob set counterclockwise pretty far (not as far as it will go, but more so than in a lower idle speed direction (clockwise).
 

·
Registered
Joined
·
11 Posts
Discussion Starter #4
And: I've adjusted the valves 3 times, changed the oil and filter twice, the air and both fuel filters twice, replaced the brake fluid and transmission fluid (got a new tranny a month ago.) I haven't checked compression, but I would bet it's low. The car smokes a little, a whiteish blue. Blowby is apparent. But it runs well and goes city and highway speeds easily (a little too easily, whoever said these cars were slow didn't meet mine...)
 

·
Registered
Joined
·
11 Posts
Discussion Starter #5
One more thing (I'm tryin to provide enough info to cove initial questions). The glow plug light sometimes blinks. Not everyday, but occasionally. It did not before I replaced the two GPs, which was about a month ago.
 

·
Registered
Joined
·
6,118 Posts
Sounds like the starter is worn out, but first check all connections at the starter, and the ground wires. Replace it with a rebuilt Bosch starter for a 300D turbodiesel, its more powerful.
 

·
Registered
Joined
·
10,152 Posts
^ Agreed.

Do you have the early style glow plugs? the ones with the wavy wire between them? If so, if one is bad, one will get power.
 

·
Registered
Joined
·
103 Posts
Sounds like a worn out battery or alternator. They don't hold the charge on cold winter nights as well as during 40f days. 50amp charge will fry the battery in a hurry. Emergency portable jump battery may be ok. Put it on 2amp overnight charge and if it turns over fast in the am you know you have a weak battery or alternator or connections and the starter is fine. You could get them both tested for cheap at sears or other battery stores.

Check to be sure there is 12v+ at the glow plug wires. (there is a good post about this testing)

The block heater car work wonders. If it is a low amp heater it will need to be plugged in for up to 10 hours. If it is a high amp heater it could heat the engine in one hour. When my block heater worked it pumped heated antifreeze through the system and was over 100f after one hour. Started nice even with bad glow plugs.
 

·
Registered
Joined
·
1,418 Posts
I wrote the following then posted. After re-reading your post, I am thinking about oil. What oil are you using? It it fresh? Try a recommended lighter oil that is for colder temperature.

I am leading toward the battery being bad. A fully charged battery should read about 12.7 volts after it has been off the charger for an hour or so.

-Clean the battery terminals with the proper wire brush tool.

-Charge the battery on the 10 amp setting until is sees about 15 volts. Do not hold it here for very long. These large batteries can take days to charge on 2 amps.

-The engine should crank good now. If not put the charger on the 50 amp setting for 30 seconds. The engine should crank good now. If it does the battery is shot. If not report back and we can cover that.

-To test the charging system, measure the voltage when the engine is running. It should be 13.7-14 volts. I know from experience that certain alternator failures will not be relieved through the charge light being on.

-If you do get a new battery, charge it to 14.4 volts on the 10 amp setting before use. This will make it as healthy as possible.

Let me know the results and I'll provide more information if needed.
 

·
Registered
Joined
·
11 Posts
Discussion Starter #10
thanks for your advice. I do have the pencil style GPs. I just got two new ones today, and am goin to put them in tonight. There are already two new ones as of a month ago, so I am replacing the older ones. My battery after 8 hrs (while I was at work today) wouldn't get the car the turn over hardly at all, and fizzled to nothing. It still read 12.4 amps even then. I then had the car hooked up to a truck for 20min and finally I got my car to turn over enough to start. I've cleaned the posts, and wires that I can see. I'm stymied. Also, my dash lights do blink off and on (really only the seatbelt light), and the gauges flitter sometimes. I'm wondering if I have a wire that is touching the chassis but haven't gone on the hunt yet. Would a problem with the glow plugs or relay prevent the battery from deliverying electricity to the engine to start it? Because I have full power, lights radio etc, and the battery will seem dead (but as i've said I'll test it and it'l be fully charged.) I did have the battery tested at the shop and they also confirmed that it was fully charged. The battery is a year old, and is a 650, should I get a higher rated battery (I had thought I read somewhere that these diesels needed larger batteries (not nec size, but amps). Thanks again. Oh! PS, I am running 15w40 and I just changed the oil and filter over the weekend. It's hard to get a diff grade of oil (for diesel) here at the auto stores. But perhaps i should switch to a diff grade?
 

·
Registered
Joined
·
1,418 Posts
When you crank, what does the voltage measured at the battery drop to?

Glow plug problems would not affect cranking. Unless it causes you to crank so much it depletes the battery.

Per the owners manual 15-40 is OK to use down to 23 deg F. What is the temp where you are at?

The battery should fill the battery tray. Don't know what size this is.

Sounds like that you may have a grounding problem from your description of the lights and gauges.

Did you charge and test like I mentioned in my previous post?

12.4 volts indicate about 75% charge.

You are mixing up your volts and amps.
 

·
Registered
Joined
·
103 Posts
Sounds like the starter is worn out, but first check all connections at the starter, and the ground wires. Replace it with a rebuilt Bosch starter for a 300D turbodiesel, its more powerful.
After you do what Commuter advised and you know you have a fully charged battery and have checked for broken wires, shorts in the ground wire, loose wires etc.(wires can be broken internally) it may be the starter as 79mercy advised. Check a friends voltage when the engine is off to compare the batteries. Just keep in mind there are different time limits when charging batts. at different amp settings. It is possible to wear out a battery from too much quick charging but I have not seen it happen to a 1 year old battery.
 
1 - 12 of 12 Posts
Top