So my 1983 200D had some issues starting since I bought it - the starter was failing with complicated matters but even when it would engage it would not always start on the first few tries. Fiddling around with the primer pump, disconnecting/reconnecting fuel lines, etc. are things I tried but I don't know if they were what got it working or if it was just coincidence. The fuel filters are both brand new. The primer pump does leak a lot when I pump it (old plunger style), but does not seem to leak otherwise. I installed a new starter and that had it working quite well for a short time.

Now it will not start at all, no matter how much I try. Could it be that the fuel pump is not working? How do I locate/test this? Any other ideas what could be wrong? There is plenty of fuel in the tank and it flows freely through the lines if I disconnect the hoses under the hood.

Do you know to cycle the glow plugs & wait for the yellow glow plug lamp to go out before operatng the starter ? .

And then , never let off the starter until all four cylinders are firing as you hold the thorottle a little bit open ? .

Have you tested the glow plugs yet ? (easiset way is with a Harbor Freight cheapo infrared thermometer)

Have you adjusted the valves yet ? (the # 1 cause of hard starting and scrappage of perfectly good old Mercedes Diesels) .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

It could be a failed lift pump. Pull the fuel line off it while cranking and see if it's pushing fuel. It's more likely that the primer pump is leaking fuel. As a temporary fix you could put a balloon or condom down over it to seal it off. It should be replaced if it leaks. Are your glow plugs working? Failed glow plugs is a far more common cause of a no-start condition.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

This might sound obvious so don't take offense, but is it cranking at all? If it's an automatic, apply the parking brake, put the shifter into neutral, then try starting it. Maybe your shift bushings are bad. If you have a stick, forget everything I just said.

__________________
Never be ashamed to ask for help.

1985 300D
1987 300SDL
1970 Jaguar E-Type OTS
2002 Dodge Intrepid (Traded In)
2011 Ford Crown Victoria

Of course. I have several other diesels and these are not my first. All glow plugs test good and voltage is going to them correctly.

There is zero firing at all.

No, but it runs very very smoothly when it does start, and there was a guide for this under the seat when I bought the car, so I suspect the previous owner did this in recent history. The point is not rough running, but it will never start, it is as though the car is out of diesel.

I have a replacement newer-style primer pump somewhere - I'd bought it brand new for my 300SD but then ended up getting a Monark metal plunger-style one that I liked a lot more...I just need to find it. It's a real pain to get the old one off though. Which line are you talking about pulling off? Can you post a picture?

It's a manual. No offense taken, I know a fair bit from experience but there's plenty I don't know, and any guesses at help is always welcome.

O.K. , nothng is ' of course ' , you'd be amazed at the things Mechanics see on a daily basis .

Voltage to the glow plugs doesn't mean they're working but I agree , it does sound like poor fuel flow at this point .

The old style hand primer pump is supposed to leak as you pump it , that's why you have to lock & unlock it , to stop that leaking when the engine is running .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Can you elaborate on that? I don't think it's true. I've pumped them without any leaks.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Sorry...didn't mean to offend.

I've also taken each one out and connected to jumper cables to see them glow. The glow plug relay was formerly bad and never turning voltage off - I replaced that a couple weeks ago and checked all the glow plugs then. The only other thing I know to try is to pull the injectors out and see if I can see them all glowing through the holes.

Okay, then any other ideas what the problem could be?

The ones no longer made but still on many parthaus shelves , it is preferred and every one I've ever seen , leaks when you're pumping it ~ even the guys like you who bet me it won't and then pop their hood....

Mercedes says it's supoosed to leak when pumping so I trust them .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

The engine is old. This increases the possibility of compression issues.

First though loosen an injector nut to verify if fuel is there or not. This may take one person watching and another cranking. There are a whole list of possibilities but if you do this first we could all progressivly follow a course of action. If the primer pump is leaking diesel change it.

It is a simple o ring on a barrel assembly I imagine although I never took one apart. If fuel is getting out air can be getting in. You cannot draw fuel from the tank if the vacuum that the lift pump creates is ruined with an air leak. Or even if the vacuum is not totally ruined the amount of air mixed with what fuel is available upsets the applecart.

If you have no fuel supply spraying some wd40 down the intake with the filter not in the way of the spray. This with someone cranking to see if it is capable of running with an alternative fuel source. If you post the results of the above there are many on site to guide you further if required.

If you have a working block heater it will not hurt to plug it in and warm up the block to aid combustion for the spraying down the inake manifold test. For those that have wondered about using wd40. As far as I can tell the propellent charge in the can is/was propane I picked up somewhere. Diesels fire nicely on propane.

I am a firm believer in simple tests to eliminate too much cranking and stress on the starters. Nothing like an old starter deciding it has had enough of the abuse about halfway through attempting to find a problem.

One of these days I am going to get my ir temperature gun and shoot the temperature of the squigly wires between the old style series glow plugs to get a benchmark of what temperature they should be after say a twenty second well timed glow plug initiation. This is another simple test to establish that they are drawing plenty of current. I have not had the time to establish a bencmark of what temperatures one should expect. One of us will soon though as it should be a great time saver.

Obviously the hotter the temperatures seen the more current is flowing. Get your own benchmark on your own system while it is working well. Useful at a future time if you suspect there is a problem. One of my old cars still has the series plugs and it functions well with them so they will remain.

I'm pondering this , it's always diffucult to diagnose when I'm not there to observe...

If the glow plugs glow when tested , they're all fine . no need to remove them when a $19 IR Thermometer will do the job in situ , it also helps pinpoint many other heat related issues .

I don't know where you're at , if cold , maybe gelled fuel ? . that'd create a no fire on any cylinder condition .

If it was trying to start , I'd suggest running a hair dryer in the grille intake , this sounds goofy but really works well , just be carefull to not melt any plastic grileworks .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Where does Mercedes say that?

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Not argumentative but subjective. We have no way of calibrating how much apparent leakage and the actual failure mode of the o ring in the lift pump.

When they start to leak usually whatever has happened to the o ring may be progressive in nature. At any given point when air is able to still get in past the o ring when it is screwed down or compressed if you will there will be issues with air in the fuel system.

Most mine exhibited some leakage while pumping with no apparent observable ill effects when I changed them. So I just saw it as preventative in nature in my situations. Another item is when mercedes wrote the manuals. They never looked at what thirty years might do to the o ring in that enviroment it lives in.

I can even see some leakge in the pumping mode as long as it is sure they seal in the clamp down mode. The ones I changed obviously still did. I also did not remember any leakage when pumping up after the primer pumps were changed. If it was there it may have been too small an amount for me to notice.

I always do anything that even might be preventative in nature. I find that most issues over the years that created a road breakdown cost me a days time and wrecked my schedule totally in one way or another.

The final clincher is by experience many have found that replacing a leaking primer pump fixed their problem. It has to be a given that the manual did not cover every contingency as well.

Maybe the o rings just rot with time perhaps. I cannot see them getting wore out as they are seldom if ever used. Then again if there is no oil on the bore and aluminium oxide has formed they might get chewed up a little if used. My point I guess is that perhaps nobody really knows exactly why they start to leak other than the obvious that fuel is getting by the o ring.