1992 300E (193,000 mi.) sat on a train for 1 month in transit. Upon receiving the car, it ran rough and stalled with difficult restart about 2 miles from the receiving point. Car restarts rough and runs a few hundred feet, then stalls. Similar symptoms as having wet wires after washing an engine, but the engine compartment is dry. Had to tow the car home. Car ran fine as daily driver 1month ago.

Fuel filter replaced 34,000 mi ago
Distributor cap & rotor plus ignition wires replaced 28,000 mi ago
Spark plugs replaced 6,000 mi ago

I don't know where to start whether this is an ignition problem (cap & rotor) or a fuel supply (fuel pump?) problem. Thanks in advance for your advice.

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ARVY

1999 E430
1999 C230 Kompressor
1992 300E (write-off)
1984 190D 2.2 (sold)

This sounds a lot like what I went through with my 300E (slash am still going through, but its almost done). Initially the problem with mine appeared to be the cap/rotor, which you can check by just taking off and inspecting. Mine had all kinds of carbon soot built up on the contacts of the cap, and the rotor's metal contact was corroded away. Replaced those and the car started up again.

However, there are some other things to take a look at too. OVP relay seems to be a problem sometimes (I actually have one for the later model cars that I'm not using, just acquired from a junkyard w/ 15pins), but also fuel pump relay. There is a bunch of information in a couple posts if you search for something like "300E no start" or "300E rough idle", such as resistances on different sensor you can measure.

If I had to do this all over again, I would start by checking for spark first, just pull a plug and crank the engine to see if you have spark, and if not, or if it is weak, then its an ignition issue.

My mechanic told me how to check the fuel and test for pressure at the same time by undoing the fuel line to the distributor and seeing if there is fuel, and then also checking the return line just after the valve to see if there is fuel. Apparently (and I may be wrong, Portuguese is not my first language, and English isn't my mechanic's first language lol) if there isn't any fuel in the return line then pressure is good. The only major components in the fuel system that can cause big problems are the fuel pump, distributor, and injectors (injector seals too I believe).

If I had to guess, I'd say your problems lies somewhere in the electrical system, because the semi-mechanical fuel injection on the m103's (you do have a 103, right?) doesn't really fail.

Hope this helps, and do a quick search for the no start and the rough idle.

John

edit: what ended up fixing my car was the CPS at the bell housing, a new EZL box, and new plugs (after the OVP, Fuel Pump Relay, Cap/Rotor, and misc other tweaks)

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87 300E
202k on the clock

John: thanks for your reply. I do have an m103 engine. Like you, I am leaning towards the replacing the CPS (the one that goes from EZL to the flywheel towards the rear) as a starting point, then go from there. My rationale is start from the oldest part first, since my cap, rotor, wire, plugs, and fuel filter have been replaced less then 40K ago. If the CPS change doesn't solve it, I'll see about the fuel pump stuff. Thanks for your suggestions.

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ARVY

1999 E430
1999 C230 Kompressor
1992 300E (write-off)
1984 190D 2.2 (sold)

The CPS is a fairly expensive piece ($140ish on Fastlane, $131 on Foreigncarpartsonline.com) so you might want to try to ovp and other associated relays which can be easily had at a junkyard.

If you are going to do the CPS though, your best bet is to get to it from underneath the car. Its held in by 1 5mm hex bolt, and its kind of a pita to get out - I ended up sending it to my mechanic to replace, because I couldn't get the thing out of its seat at the flywheel. Also, if you have good spark, then this can't be the issue, because of the way a CPS works. It shouldn't be bad if you have spark. There is an article on here in another thread that explains all about it.

The rough idle/hard start can be an expensive problem to just throw parts at, so your better off doing tests on different components to rule things out. I would guess that its not a fuel delivery problem, but there are ways to test that as well without throwing parts at the car.

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87 300E
202k on the clock

Replacement of Crank Position Sensor solved my problem. No stalling, no dificult start. 300 miles of highway driving on the weekend- engine smooth as ever. Thanks!

Tech charged 2 hrs. labor for installation.

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ARVY

1999 E430
1999 C230 Kompressor
1992 300E (write-off)
1984 190D 2.2 (sold)

I just had the valve cover replayed on my 93 300E, and in the process of doing that they "discovered" that the wiring harness was shot. Turns out all of the insulation of the wires controlling the engine and spark were breaking up and allowing shorts to occur.

Apparenlty there is a service bulluten on this problem.

Hope it helps...expensive buger though - $900-1200

Thanks for your input; however, the wiring harness was not a big problem on an M103 engine (up to 1992). It is a known issue on the M104 which your car has (1993 to 1995 on the W124 chassis and 1996 to 1997 on the W210 chassis).

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ARVY

1999 E430
1999 C230 Kompressor
1992 300E (write-off)
1984 190D 2.2 (sold)

I have a W124 300E gas MBenz, which engine(103983 6cyl) is with some noise and spartk plugs must be clear frequently. I´m thinking to rebuilt this engine and I like to know which parts and sizes should I have to buy beyond the piston ring set, main bearing set, block lower gasket set, cylinder head gasket set...
A am in Brazil and I have to import this spare parts
Thanks

congrats arvy, wish my engine issue was as simple to fix as yours - best of luck to you in the future man

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87 300E
202k on the clock