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-   -   '81 300 D won't start (https://mercedesforum.com/forum/diesel-discussions-33/81-300-d-wont-start-34245/)

djgonzo 01-05-2009 10:24 AM

'81 300 D won't start
 
Just my luck... I purchased an '81 300D this Sat. with 213K on the clock. I had previously driven the car twice and it started and ran with no problems. I drove the car (after purchasing it) back home (20 miles) and around town starting it with no problems 4 times or so. That was Saturday.

Sunday morning the car wouldn't start. The engine turns over and at times sounds like it wants to start but doesn't. I called the prior owner, he suggested I replace the small plastic fuel filter. I did this and the car started with a little effort. I proceeded to take the car on a little drive, 6-7 miles or so and the car worked fine.

I thought my problem was solved until I tried to start it this morning (Monday 1/5/09) and it seems to have the same problem it did yesterday and it wouldn't start.

I'm thinking it has to be something with the fuel system right?

I'm new the these cars so any suggestions would be greatly appreciated. The only thing I did before these problems started was fill it up with gas. Yes, I used diesel not gasoline.

TIA

djgonzo 01-05-2009 05:05 PM

RE: '81 300 D won't start
 
Could my problem have to do with the glow plugs?

cycleboy 01-05-2009 05:43 PM

RE: '81 300 D won't start
 
Your problem could be glow plugs, fuel delivery, low compression or a variety of other issues.

You have a new (to you) car. Unless he gave you a folder full of verified receipts, assume that the previous owner was the worst owner in the world. Give the car a complete tune-up (valve adjustment, filters, oil change, glow plugs, etc) and then see what doesn't work.

jimishadow 01-05-2009 06:31 PM

RE: '81 300 D won't start
 
if you pump the manuel pump on the side of the injector pump does it pull back when you pull it up?if it is its most likely the screen in the fuel tank. it can also be a clogged main filter[llooks like oil filter on top near ps pump.]

djgonzo 01-07-2009 06:31 PM

RE: '81 300 D won't start
 

ORIGINAL: jimishadow

if you pump the manuel pump on the side of the injector pump does it pull back when you pull it up?if it is its most likely the screen in the fuel tank. it can also be a clogged main filter[llooks like oil filter on top near ps pump.]
The manuel pump works fine, when I push it down if pumps gas into the small filter and rises back up. Is that what you were asking?

djgonzo 01-07-2009 06:34 PM

RE: '81 300 D won't start
 

ORIGINAL: cycleboy

Your problem could be glow plugs, fuel delivery, low compression or a variety of other issues.

You have a new (to you) car. Unless he gave you a folder full of verified receipts, assume that the previous owner was the worst owner in the world. Give the car a complete tune-up (valve adjustment, filters, oil change, glow plugs, etc) and then see what doesn't work.

Thanks for the tip! I plan to do all of the above. Right now I'd like to get the darn thing started again as it was running perfectly Saturday. All of the sudden it just won't start. I'm thinking it may be the glow plugs as I don't have any receipts showing this was done recently. How hard is it to replace them and where are they (glow plugs) located?

Is there a wire that connects to the glow plugs that could've come loose?

Thanks for the replies, as I'm new to these cars and diesel's in general.

boblo_home 01-07-2009 06:44 PM

RE: '81 300 D won't start
 
It looks like your car starts well when warm and not so well when cold. Was the car warm when your test-drived the car? Never ever test drive a car ( diesel in particular ) when it is warm. Insist to look at it first thing in a cold morning to try to 'cold' start it.

Now you are are stuck with the car, I suspect it is low compression. Try changing all filters as suggested by the other readers. If the glow plug light goes out then at least 3-4 glow plugs are working. If more than 2 are gone then the light would not go off. The only way to find out is to take off the cover of the glow plug relays and measure the resistance. They should be less than 5 ohms to chassis.

Good luck.

djgonzo 01-08-2009 12:37 AM

RE: '81 300 D won't start
 
So I spoke with the previous owner and he suggested that I put the car in neutral, and then turn the ignition on. I did so and the glow plug light came on then went off, put the car in park and it fired right up! It seems like the glow plug light won't come on while the car is in park but will when shifted to neutral. I repeated theses steps a few times and the car fires up immediately. BTW, it is cold outside.

The previous owner remembers this happening on a 300d he had a few years back but says it hasn't happened on this car before.

I test drove the car twice, both times in cold weather and didn't have to do this before nor did I have to do this Saturday when I bought the car and drove it all over town turning it on then off 6-7 times while in park.

Any ideas as to why the glow plugs go on/off in neutral bu not in park?

jimishadow 01-08-2009 10:32 AM

RE: '81 300 D won't start
 
it pumped normal...fuel is fllowing...if you pump it and it pulls bac down when you pull it up the screen in fuel tank is clogged.

cycleboy 01-08-2009 01:48 PM

RE: '81 300 D won't start
 
Because your neutral safety switch is faulty/out of adjustment.


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