Isawelvis

I have a problem with it just dying on me especially when slowing down to turn or slowing for stop light. It will crank and start up and immediately then die. It seems to happen after it has been driven for a while after I 've stop to go to the store, it happens. . It always starts when I get in it but then cuts off. IF I let it set awhile it will start and be OK . Have had new injectors, distributor cap, rotor and coil install. Still does it. I just drove it yesterday (continuous) on highway and no problems I have tried to let it idle for over 30 minutes and the cut off never happpens. I had this same problem prior to new injectors, and other stuff above. Car runs smooth on highway.

thoughts?

dolucasi

If you are 100% confident of your ignition integrity, this has to do with your idle control, and specifically it transitioning from running to idle.

Is this a manual or auto transmission? This is even a bigger problem in manual transmissions as the auto's most of the time hide the underlying problem.

190Efan

I think Dolucassi is likely right about this given what you've already replaced. I'm just wondering what the condition is of the fuel filter, fuel lines, fuel pump and gas tank? It might also be that some combination of these might have restricted fuel flow that doesn't show up until after the car has been driven for a while. These are easy to check without spending alot of money. It's best to start with the easy and inexpensive to check items to rule them out and then work your way up the list of possibilities. Throwing parts at a problem that doesn't solve the problem can get very expensive very quickly.

Isawelvis

To Dolucasi - it is an automatic. As far as being confident on the ignition system, Ieave that up my mechanic since I have limited knowledge . I do think you are right about the idle issue,. Will do more research on that. The idle does flucuatate some when slowly down to make turn or putting it in gear.

190Fan - I think it is a fuel issue vs electrics. and the car will always crank
Before replacing all the parts listed, the car was stalling much worse. the mechanic finally after all the work above said it ws a bad coil????????
The fuel tank was replaced by the former owner

One of my biggest problems is finding a LOCAL mechanic to work on it without having to drive long distance to Mercedes/Bosch specialist.

Im thinking maybe replace the cap and rotor with the electric module type, like I used to do back in the 70s. Not sure they still do that.

Thanks for the response though.

dolucasi

Unfortunately, most indy mechanics or even the dealer mechanics these days do not know these cars well enough to properly diagnose and fix this specific problem you have. They would not even know where to begin and start replacing parts. They do not have OBD2 or better diagnostic tools for this era either and forget about reading any codes on this issue.

I'm 95% sure that this is an idle control issue. When I got tired of my manual transmission dying on me in between shifts I had to diagnose the problem mostly by myself with some on line help. That was 5 years ago and my car has not stalled on me ever since after the fix. You can imagine manual transmission amplifies the problem because your rpm is dropping like rock between shifts.

So the idle control has a few mechanisms to avoid stalls when the car/engine is slowing down. In your case one or more of these systems are failing you.
Here are the mechanisms.

(1) Throttle switch + microswitch: properly senses the plate and pedal positions to activate idle control loop
(2) Idle control in the ECU/MAS (depends on MY) could be intermittently cutting out due to electrical problems like OVP, could also be that the ECU/MAS is failing altogether for this case only.
(3) Hall effect sensor loop - Senses if the tires are moving at all, when the idle transitioning is happening. If the engine rpm is dropping from >1800 rpm and you let off the gas pedal it maintains idle >1000rpm for a while and at that point eases the rpms slowly to the normal 750rpm.
(4) Fuel cut off - The ECU senses when the fuel should be completely cut off when appropriate and by means of the EHA valve turns off the fuel flow until the engine rpm's drop to about 1200 rpm.
(5) Have I missed any other??

Happy motoring

190Efan

You don't want to blindly replace the cap and rotor unless you know that they're at fault, for example moisture in the cap. Throwing parts at a problem without knowing whether the parts are actually at fault can get very expensive very quickly. It's possible it might be the ignition coil but I don't think it's so likely since the car does start. It might be some sort of fuel system debris blockage that doesn't show up until after the car has been running for a while which then gives the possible debris in the system the chance to clog it up. I think Dolucassi is again likely right with the idle control valve which is likely causing the car to idle at too low a rate to keep the car running. Since you say you have limited knowledge, I think your best bet is to find an older MB specialist to take your car to to have them properly diagnose the car and get it back into running order. That would be well worth the drive and less expensive in the long run because you'd have someone working on the car who can properly diagnose it and get it running without throwing a bunch of expensive and unnecessary parts at it that likely weren't the problem to begin with.

Isawelvis

thanks Dolucasi -I will pass this on to whomever I get to work on it. First I will try to find someone who specializes in the Bosch injection system for this age car. As far as question 5 I have no clue but your info gets me well on the way to fixing this issue. and for 190E fan you are probably right.
thanks again

dolucasi

I expect a mechanic to know about #1. If they do not know how all that works I would move on to the next shop.
I do not expect a mechanic to know details of #2, #3, #4 or how to diagnose them.
This is why all of us need to know these items when diagnosing this type of problem even if it is merely for communicating with a mechanic's shop.
Basically you need to know more than the mechanic.

One more item is that there is one gauge that is desperately needed in a 30+ year old KE-Jetronic system in any W201 dashboard.
It is easy to install and with it you would not even need forums to answer items 2,3,4 in the above list.
You would also know how your Emissions system is functioning, if your EHA is aligned, if your AFM plate is adjusted correctly, etc, etc., at all times.
I know I have advocated for this in the past, just repeating the same here in your post.

BTW, does your car stall if you are coming to a stop and before you stop you throw the gear into neutral? Just curious.

BetterDaze

I believe the O2 sensor is severely underrated as far as it’s contribution in preventing stalls. I spent a lot of time chasing fuel delivery suspects(Pumps, injectors, EHA etc.) and idle and ignition(EZL, cap/rotor) issues based off a random stall at lights or getting ready to turn.

It kept stalling but as soon as I swap the O2 sensor i was able to start daily driving the car with no further issues. It still ran the same as before as far as idle rpm but engine no longer quit

dolucasi

Yep, the EHA current meter in your dash will also show you if there is a problem with the O2 sensor.

So basically if any sensor, actuator etc. is acting up, the EHA current meter will inform you there is a problem, as long as you understand the system.
This is why I say it is essential for a 30+ year old continuous injection car.

190Efan

This is also why you shouldn't throw parts at a problem until you determine for sure that the part you're replacing is actually at fault. Throwing parts at a problem and hoping doing so will fix the problem can get very expensive very quickly. I was always taught to start with the easy stuff first and then work my way up the food chain until I found the actual problem.

BetterDaze

-

Isawelvis

Hard for me to figure out. When it does cut off, I can mash the gas peddle and the rpm starting jumping around but it eventually dies. Once the RPM starts dropping (could be anytime (slowing down for turn or just cruising). you can increase it by pushing gas pedal putting it in neutral has no effect. Not sure Im answering your question. What is the gauge you mention, is this one a bosch service person normally has. Remember this cutting out only happens after the car has been driven. You can let it idle for an hour and it does not cut off

I dont want to bug you guys to death, I will research it more and let you know what I find.

dolucasi

What you described in your last post is different than what you described originally. So what I have said before does not necessarily apply here.
However, when it starts the stall, is your foot on the gas pedal or off the gas pedal. Or can it start the stall in either case? This is key.

The gauge I described does not exist commercially. It sits in your center console right next to a voltmeter in my car. I had these custom made for our 190's by a reputable company.
I constantly monitor the EHA current which is the final output for emissions control. Therefore you are seeing all of the sensor's effect on that current. I can even tell if my AC compressor is running because even that effects some the EHA in an obscure way. Things like OVP cut off is ridiculously easy to see as well.

For these intermittent stalls, it is invaluable in diagnosing because you are seeing the ECU's final output as the stall is appearing. And it is important to have an old analog gauge as opposed to a digital one that will always jump around and hard to see.

You do not appear to be a DIY person, but it is rather simple to install if you were. I'll re-post a picture if anyone is interested.

The alternative is to not permanently wire this in but to pull wires in to the car and attach a current meter to it temporarily and drive around with it and monitor your EHA current.
There are breakout harnesses sold for EHA current reading. They are available online. And for this a digital current meter could be used.

190Efan

The more specifically you can describe exactly when your car dies and stalls, the better the chance we have to help you properly diagnose your car and get it back to working properly.

Isawelvis

Thanks guys. I checked back on prior maintenance and the 02 sensor has been replaced. I am reading your post and trying to get the info you request. Yesterday, I started the car ( outside temp about 60 degrees) First try to start it stumbled ad died but second time started. The RPMs idle at 1000 (smooth)for about 30 secs and then dropped to 700, which was not smooth but constant. I try the AC on to see how the idle would work and the idle increased. Turn it off and idle when back to 700 (again not smooth) . Put the car in gear (R) and engine rpm drops and very rough, Its this way until I go do D and then once i take off its smooth.

Back to dolucsi comments. I Initially focused too much on engine just cutting out when turning, It never happens if I let the car just set and idle. Have tried it for 45 minutes and is OK.

It does happen when driving. Could be cruising down highway and it cuts off. or when I slow down to turn off interstate or stopping at light. It never seems to happen on short drives ( ie less than 10 minutes) usually 30 minutes or more.

Thanks, again, its not your guys responsibility to fix it for me but I do appreciate your responses.

190Efan

Your car should start right up the first time. Since you're having trouble with that first start in addition to the other symptoms you're describing, it leads me to suspect that the EHA is the problem. The idle changes you're describing when you add in other things like A/C are likely the ECU trying to compensate for the bad EHA. Last year my car was starting to have trouble on the first start which was unusual for it and it turned out to be the EHA. Since we have the same year and engine, I suspect that the EHA is the problem for you as well.

dolucasi

Good comments by 190EFan.

I would first rule out item "1" in the list of post 5. That is the low hanging fruit. And it can be easily checked by a knowledgeable mechanic
Once that is checked out as 190Efan mentioned above, it sounds like either your EHA is not working properly or is slow to react to fuel cut off.
That could also be that your ECU is slow to "undo" the fuel cut off. In other words slow to react. That is item "4" on that same list.

If you did not know this, the fuel cut off does not engage until the engine reaches full operating temp. This takes 5-10 minutes after you first start an engine. Sounds like you are also observing this during your stalls after a warm engine.

It is unusual to have EHA electro-mechanical failures before the EHA starts leaking which is about 100K miles with good fuel. But that does not mean it never happens.

If you want to make sure this is your problem you will have to observe the EHA current like I mentioned earlier while you are driving in the car and verify that the engine stalls only after the fuel is cutoff.

Another way to verify this is for you to take over of the ECU's responsibility. Meaning when you are slowing down as soon as the rpm's drop below 1800 rpm, down to between 1400-1800 rpm, pulse the gas pedal. I mean to momentarily tap it to disable the fuel cut off early. Does the car ever stall if you do this? By "ever" I mean try it at least 10 times maybe more to make sure you are not observing a false positive.

There are other ways to verify this. But it starts to get involved. There is one other condition that disables fuel cut off. You guessed it..... Your AC compressor being on disables fuel cut off.
I suspect that the likely hood of stalls would be much less likely if the AC is on and the compressor is running. You can even fake the ECU to think the compressor is running all the time but that could get involved.

Dave Kost

Here is the Factory Trouble Shooting Document.

I would confirm fuel pressures and volume
Get % reading at X 11- this is a biggie
Clean all electrical terminals, relay's, sensors, grounds, replace fuses.
Trace all electrical connections at 25 pin ECU connector.

Even though the car runs mostly ok doesn't mean the mixture is set correctly. The mixture could be set such as it is out of the range that the ECU-EHA can't make the right correct fueling, and therefore a stall or dip in idle.

Monitor running battery voltage looking for any spikes or drops when the stalling happens.

It isn't easy these intermittent issues.

Isawelvis

Thanks for all the info, and I have taken a lot of notes. Currently I have put the car and the issue on the back burner to house moves and other things. Car is in temp storage for a while , hopefully will get back too it. Again thanks.

190Efan

Some good advise for testing and also cleaning all of the electric connections. I would also point out that MB pretty much designed the KE-Jetronic system to not be adjusted for the reason that an incorrect adjustment would cause the issue that the OP is currently experiencing. It's possible that a previous owner might've been the one to adjust it and that might've led to the current issue. You might want to contact the MB Classic Center to find out what the original setting was when the car left the MB factory and see if you can get your car back to that as a benchmark and then see how it behaves.

Isawelvis

Getting back to m 190E issue of dying on me after being driven for awhile, will restart and then die again. I appreciate all the past comments, they have been helpful Recently I remember when I first bought the car, back in 2022, I had a hard time getting the gas cap off. I asked on this site, why it was so hard to get the gas cap off. I was told the system was pressurized. At that time the car was running great. Then last year the car started having issue. I have since noticed there is little pressure when taking off the gas cap to refuel. So I recently replaced the Fuel pressure relay behind the battery and low and behold I have the pressure back on the gas cap and the car is not cutting out. Recently drove it 30 minutes with a couple of stops and no problems. if you read my prior post above I have new injectors, new O2 sensors and other stuff. I now think if it a fuel pressure problemall along. I plan on
replacing the fuel pump, filter and accumulator.. Any thoughts.

dolucasi

I think you meant the Fuel pump relay, but that has not much to do with the air pressure built up in the gas tank. I doubt the two are related.
Now the Fuel Pump Relay cutting off can cause stalls, that is for sure but would not effect the air pressure in the tank. That is more of a mechanical "thing" not electrical.

I would not recommend replacing parts blindly not knowing how old they are especially if you are not replacing them with OE parts. Because quite often replacing a perfectly functioning factory part that is superior to a new aftermarket part. So replace them as the start to fail, or if they are at the end of their natura life. For example a fuel pump life is 100Kmiles to 120K miles, so replacing them before they fail at that mileage is fine with another Bosch unit. My accumulator was still functioning at 200K miles, when I replaced it. Life expentence also depends on other factors like climate, fuel quality used, etc. etc.

BetterDaze

The high tank pressure such as the cap being tough to twist and basically blowing off and your stall description remind me of my initial issues, do you hear gurgling in your tank when turning the car on or off at all? And how does it behave when it’s low on fuel vs a full tank?

If everything else seems to check out then I recommend checking the fuel strainer too and Inspecting your fuel system back to front in general. In case of the blocked strainer the fuel pumps will be able to pull fuel but struggle as you drive and the tank sloshes around debris that occasionally blocks the outlet/strainer resulting in an inconsistent stall and the increased pressure

Isawelvis

Thank dollcasi - I under the issue of just replacing parts. But if they are reasonable priced and I can do it, Im willing to take the chance. its cheaper than having someone like the last supposedly Mercedes guy charge me almost 3,000 dollars (new fuel injectors, O2 sensor, thermostat, points and distributors cap) and still not have the part fixed. I will continue to be testing the car on short drives, hoping it doesn't start again. And for Better Daze, your cap issue was exactly what I had. Story to continue.again thanks for everyone help.