my 1984 300td has a hard time starting cold. I check the glow plugs they are good and they get 12volts when i turn on the key. Some times it takes 10 tries before it turns on a lot of white ish smoke comes out and if i drive it cold it has very low power and lots of smoke, until the car gets warm and from then on there is no problem restarting or power. what should I check next? thanks

Can you elaborate on the tests you performed to confirm the glow plugs were good?

On a related issue, when these diesels have a hard time starting when cold, you should only try once, not ten times. Just keep the starter engaged until it runs. Even when it starts firing on one or two cylinders keep the starter engaged until the engine can run on its own. That's the procedure MB recommends. Starting a diesel when cold is not the same as starting a gas engine when cold. The starters are designed to be used this way. Repeated short starting attempts do not allow the cylinders to heat up enough to ignite the diesel. Prolonged engagement of the starter allows heat to build up in the cylinders.

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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

Welcome to the forum.

I think you're hitting the highlights of W123 ownership: climate control, hard starting, flashers. You'll want to read up on rust and leaks next.

I could assume since you're saying the GPs are getting 12V that you know the start cycle, but I won't.

You are getting the GP light on the cluster, and waiting for it to go out right?

Have you tried waiting two full cycles? Open the window and the hood, turn to position II, wait, wait, wait some more. 45 seconds or so seems like an eternity. You should hear an audible click. That's the GP relay cycling. Do it again. Now try starting.

If it's still slow, then maybe the battery is low, the starter is weak, the valves are poorly adjusted, etc etc. There are numerous threads on hard starting OM617 engines.

If the GP relay functions fine -and the GPs are okay - the next bit of advice will probably be a valve adjustment.

Confirming that the Glow Plugs are getting voltage is not enough to tell if the Glow Plugs are OK.
Go to the Diesel Giant Website and he has a Pictorial on how to test the Glow Plugs with a Volt/Ohm (Multimeter) Meter.
However, a better test is to actually pull out the Glow Plugs and use a Jumper Cable to test them on your Car Batter to see if they actually start glowing at the tip of the Glow Plug.

Another issues is that you can ignore your Glow Plug light and keep the key in the Preglow position until you actually hear your Relay click off. After that you can cycle the key back off and start over with another Preglow.
You Glow Plug Relay has the ability to stay on for about 30 seconds before the timer turns it off.

If you remove the Glow Plugs use a Glow Plug Reamer or an alternative method to clean the Carbon out of the Glow Plug Holes.

For more detailed info see the below links:
DIY Repair Links
http://www.peachparts.com/shopforum/forumdisplay.php?f=82

http://www.peachparts.com/Wikka/DoItYourSelf

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84 300D, 82 Volvo 244Gl Diesel

Try new glow plugs ,cant hurt,you can always keep the working ones as backups, fuel filters next if no go.

I checked the glow plugs with an ohm meter while they are in the engine, If the meter shows me short to ground at the terminal point I assume GP is good, if it showed me open (or very hi resistant) then GP is busted. This test always worked for me in the past. Anybody object to this test? I did wait for relay click twice and that did helped a bit, but what I had to do like one of you guys suggested was to keep the starter engaged until all cylinders kicked in. But the car use to start turning on a lot easier couple of years ago, don't know what happened. Thanks for your comments.

Short to ground is a bad plug not a good plug. You need 1 ohm or slightly less resistance.

__________________
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

I suspect that he didn't use/hasn't the right range to check these plugs because a dead short should blow the fuse

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1977 300D Lost coolant while someone else was driving
1983 300D Can't run without oil
1985 300SD (gone but not forgotten)
1990 300TE 4matic Sold
1991 Yamaha Venture
1975 Kawsaki 250 triple
1974 Honda 200CL
1951 8N Ford
2008 Wildfire 650C

The proper range with pics is shown in the DG site.
Testing these in the car should be done at the lowest scale usually something like 200.
Reading should be under 1 ohm.

If you pull them and test the tip against the body, the reading should be max or no reading even on the highest scale.

Mercedes Diesel Glow Plug Repair

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

I too have had to replace 3 bosch glow plugs that have only been about 2 yrs. I am glad the ones that were bad were the front 3 as it seems the further back you go the harder they are to get to and if I had to replace the rear one I think I would have to take off some throttle linkage and a heater hose as it is very hard to get at the plug with the oil filter canister being there also.My question is that I would like to ream out the holes when changing plugs but is it possible to get a reamer in there and if you get it in there do you just screw it in to get a good ream? I heard you can rent the reamer or use a 7 MM drill bit. Where can you purchase the reamer and I have heard differant models use differant length reamers I would need the shortest one.I am thinking I should start cleaning the GP holes out as I think the plugs should last a little longer then 2 yrs.

ZDMAK or Sam Stag sells the GP reamer for around $35.
Check e-bay, think they sell on there.


Here is a link

MERCEDES TOOLS TOOL Page (¯`·.¸(¯`·.¸ ZDMAK SPECIAL TOOL STORE ¸.·´¯)¸.·´¯)


http://www.samstagsales.com/mercedes.htm


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Is there a reamer for the loop style GP? When I replaced mine last year, I could not find a reamer. They were all for the later years.

There was a discussion about this recently. I believe the answer was that there is an expensive reamer available. My view is that since the loop is offset, it acts as its own reamer as the old plug is removed. Since the pencil plugs are not offset, they don't function this way.

__________________
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

Could be may things. Have the valves been adjusted? Have you checked compression? I don't imagine it is too cold in soCal.

__________________
81 300D Turbo 190K sold
83 300sd 319K best $500 I ever spent-daily driverw/ 2 tank WVO set up

Samstag has one, a bit pricy, $179.99, 617 589 00 53 00 for thread size 18 X 1.5mm

http://www.samstagsales.com/mercedes/mb617589005300.jpg

I found this one here on Peachparts. $95.63 with the 18 X 1.5mm thread.

BAU 917-0053... GLOW PLUG REAMER...Loop style glow plugs use this LARGE PORT-18x1.25mm threaded reamer for removing heavy carbon deposit from glow plug hole which is a major cause of glow plug failure. For models from 1967 to 1985. Non Turbo. OM615,

You could probably make one like his one, I know this is the small pencil GP, but the large one could be modifyied, there is the large plugs with the up grade to penci. maybe one of those could be modifyied better.
http://www.peachparts.com/shopforum/1797578-post47.html

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works