'91 190E 2.3...HELP! Engine died on freeway, can't figure out what is wrong w/ car.

[ezra242]

What a horrible time for my Mercedes to fail me. I need to be at my University by Tuesday and the car failed while I was on that 600 mile journey.


While on the freeway, after slowing down, I accelerated moderately. There was no pickup. Soon I noticed no power steering. In short, the engine had died.


I pull over and investigate under the hood. There is a slight BURNING RUBBER /PLASTIC smell. I think I even remember seeing faint smoke from the rear of the engine.

I cannot start the car. The engine does not even turn! The car just makes a buzz sound and I hear something cranking, but strangely the v-belt doesn't rotate. Later I discover the rotor does not turn either.

I also checked the spark plug for spark. I removed one of the plugs and inserted a random Bosch spark plug just to test it out. No spark.

I know the battery is good. I had purchased a brand new one earlier that day. I did some fundamental testing of the ignition system from what I saw in the Haynes manual. Unfortunately my car is a '91 and the manual is written for 84-88. Some of the tests could not be completed. One of the tests may have revealed a bad ESU, but I'm not sure.


I think the important thing is that the engine won't even turn. I hear something rotating, but the v-belt doesn't turn and the rotor doesn't turn. If I had broken my timing chain, wouldn't the starter at least rotate the v-belt pulley?

Any ideas? I'm going to read lots of the manual...

[xp190]

Do you hear the starter turning? if the rotor is not turning and there is no spark, but you hear cranking, then I would guess that the timing chain broke, and if that happens, it is quite a job to get it fixed. However from what I know, when the chain breaks, it is quite catastrophic and your descrition of the incident sounds more like a failure of the fuel pump, but you did mention a buzzing noise, which to me suggests the fuel pump works.

Take off the valve cover and you will know for sure if the chain is the problem, also see if you can give us any other details about what happens with the car now.

If I remember correctly 91 190s have a duel link timing chain, which is much stronger and should last a lot longer, can you tell us how long ago the chain was replaced? If ever?

xp

[stevebfl]

If the timing chain were broke it wouldn't effect the drive belts. It was stated that the belts weren't turning.

Unless the balancer has fallen off the lack of belt turning means for one reason or other the starter isn't turning the crankshaft.

[ezra242]

I haven't pulled the valve cover off yet to check the timing chain yet for this reason:

The pulley connected directly to the crankshaft DOES NOT TURN.

Nothing visible moves when I start the car. No sparks are created as far as I've tested. Fuel seems to deliver fine.

I can hear the starter spinning. I can feel something spinning (even something as large as the flywheel, perhaps). BUT NONE of the pulleys or belts turn. I agree that my failure was rather peaceful and doesn't sound like a broken timing chain. The battery has a good charge (recharged it again last night). How about the overvoltage protection relay? I'm going to read up on that. I'm trying to reconcile how my engine lost power while driving and my starter not cranking the crankshaft.

Even if my chain were busted into 10 pieces, the starter should turn the crankshaft pulley, correct??? Or could a broken chain stall the crankshaft?

[ezra242]

Ah, I made my post right after you wrote that, Steve.

So this is a real mystery to me. When I start the car, I can definitely feel something rotating. There is also a low rumbling sound.

If the solenoid on the starter isn't engaging, shouldn't I just hear a high pitched whine?

What could possibly explain feeling/hearing something large tumbling when starting the car, yet no crankshaft pulley turning.

[kerry]

If the engine was not turning, why did you think there might be spark?
I"ll take a stab with the suggestion that there is an electrical problem of some kind and what you are hearing is the slow turning of a starter that is either malfunctioning or not getting enough juice.

[ezra242]

good question Kerry -
I tested for the spark before I noticed the engine not turning at all. Funny sequence of events, but it was dark and the car had not been towed yet. I just assumed the ignition was at fault because the engine just cut out suddenly.


The starter solenoid is obviously not engaging, going to take some voltage and amp measurements by the solenoid and starter soon.

It's interesting that some event that took place while I was driving caused my engine to cut out completely and is also now preventing the solenoid from engaging. I can hear the starter churning, however. While testing the primary ignition system, I got a good voltage of ~11-12v at the diagnostic pin. Unfortunately I have no method for running the other tests since a 190E book for 89-93 doesn't seem to be published anymore. The Haynes manual runs from 84-88 and there are some differences in the ignition system.

[psfred]

First you need to verify that the engine isn't locked up. Try to rotate it using either the crank pulley bolt (27 mm) or one of the accessory pulleys (PS or AC). If it turns then, you are OK. Make sure you turn it clockwise from the front, normal direction of rotation.

I don't think you have a broken crank (you would hear that when it went), but pull the valve cover and take a look. If the engine rotateks, watch the valves, they should all move the same.

The only way the starter can turn the flywheel without the engine turning is if the flywheel is no longer connected (ie broken flywheel or crank). It is just possible that the flywheel broke free -- it will stay in place on the torque converter instead of flying off and cutting out the floor pan -- and since it is no longer attached, the starter will just spin. No spark since the spark is triggered from the flywheel.

Peter