Hey,

As I am not familiar with the 380, heres my guess, anywhere on the intake, should be 1 or 2 available vac. connections.

Great thread!

In my 190E 2,3 8v i have got a similar problem as you John. I know the engines arent' the same but here are few thing I noticed.

-Warmup stage is not notable. I have got same rpm regardless engine temp and outside temp.

-When the engine stall(no misfire) the tach drops very quickly. Engine catches and stalls for 2-3 times and then it runs fine again. Sometimes for days, sometimes for months. Could a fuel pump with insuffient delivery cause this? Then during stalling the pump gets time to pressurize system again and give enough pressure for injectors to open normally. Just my thoughts...

-During normal conditions there is a vacum pressure in the fuel tank. How would a clogged charcoal canister affect fuel delivery?

-When enginge starts again I hear the pop sound from the cat as described by John

I had also a very worn ground wire between engine and chassi. Grounding point at the high voltage capasitor and intake manifold on engine. After I did replace this wire with a new one the stalling occur more often? Could it be just a coinsidence?

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'87 MBenz 190E 2,3 8vlv

OK, figured it out last night, no it was not fuel related, it was electrical, a defective plug cap. One new wire and cap and it idles and runs as well as it ever has. Thanks to all for the help.

Now, how do I get a reduction in radio interference when the car is running....?

I will really take a look at my ignition system. I will measure cables, wiggle 'em and go thru the distributor and rotor.

John: Was the fault visible or did you find it by measurements?

Unfortunatly I have to wait until 28th before I see my car again.

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'87 MBenz 190E 2,3 8vlv

One cause of radio noise is the ignition system, the spark plug wires, caps, and spark plugs. The original wires, plugs and caps reduce noise. The radio noise should have been a clue to look at plug wires.

You may still have bad wires but they are not bad enough to cause a noticable problem in drivability yet. Over time you will replace plug wires and caps one at a time!

190dee,

You mentioned that your tach drops quickly when your car misfires. When the tack jumps around quicly, this is usually an indication of an ignition problem. When the car is moving in gear the engine speed really doesn't vary that much. The tach, however, runs off the igniton coil and will jump all over if there is an ignition miss. I would check the coil primary connections, condenser if there is one, and all the plug wires as a first step.

-John

Usually the tach drops down to zero but in a very harsh movement. From all the post I read on this forum I think I really need to go thru the ignition system.

Could the new grounding wire make it easier (less resistant) for a bad ingition cable to fail? Electricity jump over to engine block instead of giving plugs enough voltage?

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'87 MBenz 190E 2,3 8vlv

Great discussion, and I'm actually glad that you guys do the reading, I thought I was along with that

I got a 190E with similar problem, under load the car misses, and hesitates terribly, but not always, when warming up it does not do that, and then once warmed up it seems to work better, but never perfectly, the hesitation is very noticable when the cold start valve stops richening the mixture, I think that's how it goes. I ended up replacing spark plugs and wires, now I'm moving onto the cap and rotor arm, if that fails, I'm going to start fixing my exhaust cause it's terrible, but the kat is in good shape, just the middle muffler, and eventually a new fuel pump as well.

XP

From what I learned, I would troubleshoot the problem by checking the ignition system first, assuming the plugs were good (mine were recently replaced). First I would check that all the plug caps have been snapped on completely, if no joy, then check the cap and rotor for wear or deposits, if they seem OK, then check the plug wires (and the coil wire) for breaks in the insulation and resistance.

If all those things check out, fuel delivery is the next possibility. As there are MANY factors which affect fuel pressure and delivery amounts, it may be logical at that point to have the system and delivery pressures checked by a professional; (I think it is about 1.2 hours of labour by the book). That will permit you to pinpoint what section of your fuel system has the problem.

John

Over here the winter has got extremely cold (about -30 degrees celsius) and the tach problem along with the engine stalling are totally gone. Not a single time have the car made any hesitations...

Is this actually telling me that there is a connection problem? Bad wire? Plug?

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'87 MBenz 190E 2,3 8vlv

Intermittent problems are always the hardest to find.

I thought of another possible cause of your problems. I'm not familiar with the 2.3 engine but I suspect it uses a hall switch that could be going bad. It is part of the ignition primary circuit and would cause the problems you describe. Hall switches have also been known to fail when they warm up so if your car is running okay in the cold the hall switch is worth checking out.

-John

I did check the wires and cap for resistance. Visually the rotor and cap. Found black deposit on every connection and at rotor tip. The resistance was almost infinite on every single output connection. I guess it's time to relace rotor and cap, right? After removing deposits I got the 1,2 kohm there.

I checked the wires also and they all gave me 1,2 Kohm resistance

Would a "left out" ignition cause the tach to drop? Would a problem in the cap and rotor affect the tach? Isn't it td sensor that triggs tach?

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'87 MBenz 190E 2,3 8vlv