Hello -

I now have a 1981 300SD - She has stopped running and I am not sure why. A brief history is of the situation and the things that I have checked is below:

I got the car almost a year ago and it has been running fine - with couple exception being:
1. a lack of power going up hills and off the line.
2. locks, working only half of the time.
3. And lastly - there has never been or it has never worked - the interior glow plug light.

My non-starting problem, started right around the first of the year. I went out to my car and the car was completely dead - like the lights were left on or something. I jumped it with my Ford Forcus station wagon - and it started right up. I can drive the car all day long and not have a problem - but after I let it sit overnight, I need to jump it to get it started in the morning. Not every morning but most - Then it came to the point were my Focus would not jump start the car one day. So my neighbor brought out his portable jump starter. It started it. Then the next time I needed it jumped the portable deal would not start it. So the things that I have checked so far are below:

1. The ground straps - from the battery to the frame and from the engine to the frame.
2. the glow plug relay seems to be functioning - I took my volt meter and checked the tips of the glow plugs - and saw it each one get power and then drop after the timer went off.
3. Tried to start the car in neutral - no go
4. I disconnect the steel line leading to the first injector to see if it was getting fuel - I think it was but I am not sure how much is suppose to be coming out? Just a trickle or more?
5. I have removed the glow plugs but I have not had a chance to check if when I touch each one briefly - they glow red
6. I got a battery charger - the type that you can charge with 2 10 or 50 - so I know that my battery has a good charger - I even brought it into the local shop and got a load test - it passed

Things that are next
1. fuel filters - I did not think I needed this since when I was checking the fuel coming out of the first injector line - there was some.
2. check each glow plug for glow


Can anybody offer and other suggestions ?

Thanks in advance for your help

So when you go out in the morning it will not turn over at all? If so it sounds like it might be a short and that sucks.

I don't think it is a short - and if that is still a problem - I leave the negative off the battery at night now - so not to loose my juice - but I left it connect the other day and the battery juice is fine when I went to start it.

Thanks

Defective Battery?

Phil

__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]

I had a load test on the battery and - the guy told me it was ok

A load test is not conclusive.

I have a 6 Year old Mercedes Battery sitting in my garage, that passed a load test with flying colors, yet occasionally, and randomly, refused to start my car. Changed the Battery and all was fine.

How old is your Battery? If more than 5 years, its suspect.


Phil

__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]

If not the filters at the engine, your lack of power going up hills is your tank strainer.

as for the glow plugs, check resistance through them from the threaded tip to the threads you screw into the cylinder head (yeah you can do this with them still in the head...). should be about 1-2ohms. replace any that are higher or open circuit. Your no glow light could be because one or more of the plugs were bad or the bulb for the glow light was burned out.

your locks- they have their own vacuum pump in the spare wheel well, check its connections. you may also have some large leaks at the actuators in the doors and the pump cant keep up with the leak.

__________________


1980 500SE/AMG Euro
1981 500SEL Euro
1982 380SEL
1983 300TD
1983 500SEC/AMG Euro
1984 500SEC
1984 300TD Euro
1986 190E 2.3-16
1986 190E 2.3
1987 300D
1997 C36 AMG
2003 C320T 4matic

past: 1969 280SE 4.5 | 1978 240D | 1978 300D | 1981 300SD | 1981 300SD | 1982 300CD | 1983 300CD | 1983 300SD | 1983 380SEC | 1984 300D | 1984 300D | 1984 300TD | 1984 500SEL | 1984 300SD | 1985 300D | 1986 300E | 1986 560SEL | 1986 560SEL/Carat | 1987 560SEC | 1991 300D 2.5 | 2006 R350

Do a search on glow plug testing plenty documenting the procedure. They should read under 1 ohm.

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Adam Lumsden
(83) 300D
Vice-President of the MBCA International Stars Section

would tend to lead me to believe that you have some bad GPs in there... Check them for resistance although this is not a definitive check but usually pretty good.
Ream the GP holes by hand using a drill bit or some thing like that. Do no mess up the threads or peel metal (that's why I do it by hand).
After you ream the holes, crank the engine over for about 5 seconds without the glow plugs in to eject any carbon that may have fallen into the prechambers.
Replace the bad plugs. You can order them from Fastlane at the top of this page and their service is great. Not to mention that they help pay for this forum...

You can go to Harbor Freight and pick up an inexpensive Multi tester (they have one on sale all the time that will test up to 10amps, it's not very accurate but what do you expect for 3.99) that you can use to check if there is a current draw when the car is shut off. Disconnect the negative cable and (using the instructions with your tester) you can check the system for a draw. Anything beyond a nominal draw is not right. Remember that some radios and other devices will pull a small amount of power even with the key off.

If no draw then you better start planning for a new battery.

Lack of power could very well be the overbooost sensor on the top of the intake manifold. Both of my cars had bad sensors when I got them. Test (using the aforementioned tester that you bought) the top of the sensor to teh intae manifold for continuity. if this is open then the sensor is bad and it is telling your system to not boost the fuel supply for the turbo. Basically starving the engine. Your banjo bolt may also be plugged on the back of the manifold.
Do a search on this forum for banjo bolt and you should see tons of posts about it.

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

There are a lot of good suggestions here. I would also suggest taking another look at the glow plug relay. I have had the GP relay hang before and act erratic causing an unexplained voltage drop while driving. It may also be hanging up after the engine is turned off causing a battery discharge. With a voltmeter, verify that after the engine starts that there is no voltage to the glow plugs. I installed a voltmeter in my car and it allows me to monitor the voltage at all times.

TimK

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85' MB 300D Turbo
85' GMC Suburban 6.5L Diesel Turbo
2000 VW Beetle 1.9L TDI Diesel Turbo
67' Land Rover 2.5L Diesel - No turbo

So what do you do when it's so cold out your fuel gels? Smear some on toast and have another cup of coffee until it warms up outside.

Borrow a good battery and try that first.... load tests are not reliable.

When was the last time your valves were set ?

Ever tried Diesel Purge ?

Using a drill in the glowplug holes could cost you a lot of money and time... find a shop manual and read it concerning those holes.... then buy or borrow a glow plug reamer and coat it with thick grease... then when you use it the broken pieces should come back out between the reamer cutters....

Also, if you use the engine to ' blow' a glow plug hole clean then you must be sure that piston and valves are set to ' expell ' on that next movement... if not you can suck the stuff farther down into your system... blocking the tiny little holes responsible for correct distribution of the fuel from your precombustion chambers... thus messing up your power and mileage more than your easier starting will offset.

Just to clarify, when you have an unsuccessful starting attempt, does it refuse to turn over, ie:"totally dead", of does it turn over but simply not 'catch' before the battery fully drains.
This info would lead either 'away' or 'to' things like glow plugs, fuel filter, etc....

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

It would also help to put your location on your profile......a no start in winter is far different in North Dakota than it is in Miami, Fl. where you almost never need the glow plugs to start.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

Please follow the advice of Fisherman. It is spot on. You likely have two separate issues, one being the glow plugs, and the other being a small electrical leak when the vehicle is not running.

Follow the exact instructions of Fisherman to test for this leak. Please additionally note the following:

If the current draw, with everything off and all doors closed, is greater than 60 milliamps, then start pulling fuses to see where the leak is. However, frequently, the alternator is the culprit here. Take all the wires off the back of the alternator and see if the meter drops to zero.

Good luck.

Some do not believe that reaming the GP holes by hand with a drill bit is the way to go.
I have used this successfully on all 4 of my cars but this is obviously not definitive results as you could (as with any work you do) cause problems with the vehicle.
As for carbon pieces falling into the cylinders I do not know the extent of damage that can be done by a piece of carbon small enough to fit through the openings in the prechamber but I'm certain someone does.

The GP reamer is available at various places and may indeed be a much better tool that does not allow any carbon to drop into the cylinders. If you have the money then by all means buy the tools. Coating a drill bit with grease should do essentially the same thing.

I add this post because I am not a professional nor a trained scientist/engineer so this information is worth what you paid for it and I disclaim all responsibility to fitness for a particular purpose, etc, etc...

Just sharing ideas and trying to help.

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique