Need Input on Troubleshooting 1984 190D That Won't Start

I've got a 1984 190D that will not start. I removed main fuel filter & found a lot of dirt in it - cleaned it out completely & reinstalled it; still won't start. It turns over very strong; just won't fire off (so it's not starter.) Only have had the car about 6months - I am well-versed on gasoline engines, but know little about diesels. Read in a book from library that a very small particulate of dirt could clog up the needle in the injector - since I found dirt in filter, is it likely that this is the problem? The fuel pumping system is fine - getting lots of fuel to main filter and I feel injector pump is o.k. because fuel is going to injectors, but did not check the injectors themselves as yet. When I remove them, is it advisable to replace any gaskets or seals that I will encounter? As well, the book said the injectors need to be torqued down to a specific pound rating, so I'm hesitant to remove 'em and not be able to torque them right; is this imperative? Are there any relays or things of that nature that would prevent starting or is it most likely fuel-related? The car ran great prior to it not starting, compression is probably very good. Got the car 6 months ago - it sat for 5 years without being started cause former owner died. I was told, "If you can get it started, you can have it." I took a good battery to it; installed it; and the car started immediately on first fire - didn't even hesitate!! I drove it for 6 months but never changed the fluids, as they looked clean before I started it. But with it sitting for so long, could a lot of stuff be in the system that finally caused blockage or something? Any input I might receive would be most sincerely appreciated. Thank you; Michaela

Reply to
Michaela
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STOP!

First of all, one doesn't "clean out" a fuel filter, it's replaced with a new filter.

Since you opened the fuel system it must be purged of air; this can be done with the hand primer pump that's probably below the injection pump. (I don't know this model). Look for what appears to be an 7" x 1.5" aluminum pipe pointing at you that has a round black plastic top. Unscrew that top and start pumping to draw fresh fuel into the filter(s) that were emptied earlier. It should be fine after ten or twenty strokes, screw the top back on to the hand primer pump.

Then, leave the fuel system alone; that's probably NOT the problem.

Diesels use glow plugs to heat their cold cylinders prior to starting; that's the light with the coiled wire that's on the dash - it ought to light for about 10 seconds when the key is turned ON and then go out signaling the engine is ready to be cranked. There's a glow plug relay and on it, a metal fuse (fusable link). Chances are that if this is the first instance of no starting the link is broken cutting the power to the glow plugs.

The engine won't start without working glow plugs. So you need to investigate them to ensure they are working. Start by finding the glow plug relay - trace the wires from the glow plugs - 4 wires on the side of the head, near the injectors - back to the relay. The glow plug relay may have a plastic cover over the link. Replacement links are available from a M-B dealer and others for about $1 or $2 each - your car needs one - plus a spare.

If you are confident that the glow plugs are working but that there's no fuel being injected then the next suspects are either an air leak in the fuel system or that the engine's vacuum powered shut down device no longer releasing when you want to start the engine. Air leaks are fixed by being sure all fuel hose connections, filters etc. are secure. The shut down device is of the "right age" to be suspect. Its a small bellows that's on or inside the injection pump that pulls the fuel rack to OFF when you shut down the motor. The bellows wears out, gets oil logged and fails. Usually the engine doesn't stop and needs to be stopped by pressing the STOP lever on the throttle linkage.

Diesels are simple motors to maintain. Change the oil, change the filters and leave them alone. Hope this helps you.

Reply to
T.G. Lambach

I have a 84 190D too. MB diesels in this OM60x series (e.g. 601 in 190D

2.2; 602 in 190D 2.5; 603 in 300D/300SDL/350SDL) no longer use the hand primer pump. Just crank it hard. It may take more than 2 minutes to fill up the entire fuel system if you ever let the fuel tank run dry! I thought replacing the filters won't drain the entire system, unless you really let it open for extended period.

Glow plugs are important to get it start. The relay is on top of left front wheel well, a black box about 4"x4". Check the fuse strap (80A, $1 part), and check the resistence of each plug (should be around 1 ohm).

Injectors may be dirty but I would leave them as the last resort. One injector failure will cause rough but not no start. Multiple failure is unlikely considering it was running fine.

If the car has been sitt> I've got a 1984 190D that will not start. I removed main fuel filter &

Reply to
Wan-ning Tan

Ditto... I'd suspect glow plug system.

Reply to
Tiger

Excellent advice and to this specific model.

Reply to
T.G. Lambach

Just read all of your replies, Gentlemen; thank you kindly for all of your suggestions. To T.G. Lambach: the library books told me there is no hand priming pump on the 190D. Regarding the glow plugs - I will definitely check the relay and fusable link for the glow plug system and then the shut down device if I find nothing wrong in the glow plug system. Your point about changing all fluids is well-taken, and I shall do so before putting her back on the road. To Wan-ning Tan: My 190D is a 2.2, and yes, there's no hand priming pump as you said. The fuel tank never ran dry; it's about 3/4 full right now. I will check the glow plug relay, fuse strap, and resistence. Thanks for the tip on the "Cx" spec oil as opposed to "Sx" spec - that's very important, I am sure; since it uses compression to start. To Tiger: I concur. Thanks again, all of you, and I intend to start early Friday morning to check the automobile out, and I'll let you know how it goes! Regards, Michaela

Reply to
Michaela

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