Stalling Quiz: WINNER GETS $50
 

What is your best guess? Winner gets $50
Car: 1988 190E 2.3 8V
Problem: stalls at a stop or while slowing down to a stop (All random)
Parts replaced:
1. Fuel pump
2. Fuel filter
3. Fuel Pressure Regulator
4. Fuel accumulator
5. ICV
6. ICV hoses
7. Air meter rubber boot
8. Crank position sensor
9. Fuel pump relay
10. OVP
11. Temperature sensor
12. O2 sensor
13. Catalytic converter
14. Exhaust
15. Resonator
16. Spark plugs
17. Ignition wires
18. Ignition rotor
19. Ignition cap
20. Battery
21. Voltage regulator
22. Breather hose
23. Breather hose coupling
24. Fuel cap
25 EHA washers

What was done:
Adjusted EHA and Lambda
Checked fuel pressure
Checked fuel flow for each injector
Checked main fuel flow and quantity
Air plate adjusted

If your suggestion fixes the problem then you will get $50. So far this problem has lasted one year and not a single suggestion from any of the forums has provided a solution that eliminated this stalling.

Rules: You must state step by step the procedure that you would undertake. It must be replicated by an idiot like me and will not require that I end up in the hospital. In addition, replacing the whole engine or complete systems are not acceptable solutions. You must pinpoint a specific problem, support it then list and describe exactly how you would go about it.
Before I implement your solution it must be vetted. Once I agree to go with your solution there will be a testing period of two weeks before I declare you a winner.

Note: This competition is listed in several forums
I reserve the right to terminate this competition at will

Oh, I am not a troll and this is not spam!

To help you get an idea of all the details here is a thread in another forum on this problem:
http://www.benzworld.org/forums/w201-190-class/1398633-stalling-again.html

the speed sensor in the gauge cluster is loose or dead. very common on the 201s and 124s. good luck, chuck.

I had removed my cluster to fix the odometer, so I am fine with removing the cluster to check. Where would the speed sensor be? What will it look like? Why would it contribute to stalling?

The Hall effect sensor is attached to the rear of the speedo unit, left of the speedo cable connection.

I thought that the Hall effect sensor is the crank position sensor and that is attached to the EZL. I replaced the crank position sensor already.

Hall effect unit in position as per blue arrow.

http://farm2.static.flickr.com/1239/...9b697f7a_o.jpg

Heres the back of the speedo with the Hall effect doover fitted
http://farm2.static.flickr.com/1165/...213943e5_o.jpg
Have you had the air mass and the fuel distributor off and cleaned up? The air plate could be sticking.

Yes, I had those off and cleaned. I even replaced the rubber boot and adjusted the air plate with .05mm clearance all around. The fuel distributor has been tested for flow on all outlets. I also have a spare one and when installed the car still stalled randomly as it does now.
What you're describing in the photo is attached to the speedo/trip meter. I have a spare one and will compare.

So how about this little beastie?

http://farm3.static.flickr.com/2205/...880242ba_o.jpg

Yep, I checked that switch, it's fine.

I would suspect the fuel computer.

Do not want the $50, you've spend enough already.

Throttle control - always a suspect.

http://farm3.static.flickr.com/2171/...c53f0068_o.jpg

LOL, the $50 is worth the traction I get out of a post because I have posted so many times about this problem before to no avail.
I have a spare computer and that didn't make a difference. Let me tell you how seriously I am dealing with this issue: I have taken apart THREE 190Es at the junkyard for all sorts of knickknacks and I have replaced all of the strategic CIS parts as new parts.

I checked that and compared to another unit just to make sure. They both gave the same readings off line and while in the car. Statistically that means they are fine.

A new car will solve the problem.

That falls under "complete systems" category.:rolleyes:
But if you buy me a new Benz I will definitely award you the $50.:D
Now let's get back to the challenge here:)

Did you check the vacuum hose situated UNDER the whole fuel distributor assembly? That one is hardest one to get to and is often forgotten about. I would assume you have since you have done the air assembly boot which would require you to pull the entire thing off.

When you say temperature sensor, which one are you referring to? There are two. One is for CIS, the other is for the instrument cluster.

EDIT: I don't see an EZL on that list. That is the ignition brain so-to-speak. You may want to make sure its not overheating first and then maybe grab one at the junkyard...shouldn't be more than $20.

Everything under the air meter is new, new boot, new adapter and new hose to ICV.
I replaced three temp sensors actually. Once for the CIS, the cluster and the fan clutch.
I put back my EZL after I swapped it temporarily from one I got at the junkyard. No difference.

I was going to suggest this one but after reading from the beginning, I see someone beat me to it. I just had a 300E drive me nuts and it was that sucker. Good Luck.

The Professor has changed so many expensive items he just about does have a new car - at least in the engine management systems.

Professor. When you say you have tested items for spec was this statically or did you actually change the items and run them in the car with the same results? e.g. throttle control switch, EHA or throttle micro-switch.

I tested according to Bosch/Mercedes specs for CIS. Some were with the engine off and some with engine on. The throttle control switch was tested offline with an ohmmeter to make sure that it made contact upon closing then it was tested connected and power one where I measured voltage as I hit the throttle hence opening the switch. It's consistent.

What is the idle speed?

Since everything else checks out im thinking you might want to check the torque converter.

However, did you physically remove it and check for wear/dead spots on the surface? That thing can cause a lot of weird issues when worn....

I vote for that, or a malfunctioning EZL unit (on the fender)....as was mentioned earlier, it would be a cheap and easy swap with a junk yard one. In fact, the yard by me has two 190e 2.3's in it right now, I'm available to pull and sell/ship them if wanted.

Idle speed while in park is around 800 but when in gear and at a stop it's 600 or even 500 and when in gear and at a stop the economy gauge is 1/4 of the way in which my 560 SEL doesn't do at all.

I did open the spare one to check the rheostat path and it looked like normal wear. Not perfect but no spotting.

i think 79Mercy got something; does your car have a lockup torque converter? had a nissan sentra that would stall...the converter wouldn't unlock at times (computer fault not mechanical)....but i am not even sure if yours has a lockup converter

My first thought when I read this was the EZL. I have replaced several of these- They usally go completely out , but I did have one that did somthing similar to this.
Also check your coil. Make sure the leads going to it are not shorting out on the side of the coil. I had one that someone had worked on and had pushed the wires down far enough to touch the side of the housing.

They do not have a lockup converter.....I don't think MB starting using those until later (like '95-96+....)

That suggests a vacuum leak, doesn't it?

I've heard of fuel injector seals leaking air badly enough to produce rough running in K-Jet cars.

I remember when working in the tropics back in the seventies.
The job required series II Land Rover 6 cylinder versions. These cars had a lousy location for the coil - too close to the exhaust manifolds and under a leak spot off the hood. You needed to carry a spare coil around for rainy days or for going on long trips. Mountainous areas required to carry 2 spare coils and when they all 3 heated up they required an ice water soaked rag around them to keep them going.
When they were too hot - no go.

The moral of this story is that electronic components function differently under operating conditions than they do on the bench. That is why I inquired whether or not the components were actually changed out and run on the car rather than just a static test.

What is that part, I don't recognize it? Is it on the M103 as well?

Throttle micro-switch. The one in the foto is off a M103. Resides under EHA - next to Fuel distributor.

Throwing a wild dart at you. Is the transmission downshifting correctly. Downshift manually to first gear. If you are not stalling then we need to look further. Its a 1988 mercedes. Count the gears as you shift all the way to cruising speed. If you have four gears then I am going to wonder if your torque converter is coupled correctly when you are in the lower gears. Hydraulic coupling is necessary. Mechanical coupling is used to cool the tranny in higher gear. If the mechanical coupling is not released into hydraulic coupling then therin lies your problem.
Coupling from the engine to the transmission at idle is only possible in hydraulic coupling. (torque converter)

As has already been mentioned, this is impossible, because this car does not have a locking torque converter.

I just swapped it this morning, no difference, the car stalled after a half hour while going to the store.
I did however learn something about how it picks up the spinning of a disk and turns it into a signal. Pretty nifty!

I did another fuel pressure test now that I have a new fuel accumulator in the line. The fuel pressure on the main line did not go over 4 Bar. I think I am going to close this chapter and competition and call it fuel pump problem. It's new so I called the vendor and this time they took my car's serial number. Guess what, I had the wrong pump all along! A whole year of misery and all it was is the wrong part.
Thanks guys for your input.

You may want to look at one more thing. I had a simular problem that I chased for a couple of months. There is another symptom going on at the same time which made it harder to sort out, but when I finally got to the bottom of it, all it required to fix it was adding a lock washer and tightening a nut. The car would be driving fine then would stall and be completely dead. After a minute or two it would come back to life start right up and run fine. A number of members pointed me toward loose battery cables, and when I checked them they were clean and tight. I never noticed that the B+ wire was attached to the positive cable with a nut until much later. When I did, I found out that it was very loose, not even finger tight. I took it off, cleaned the wire and the stud, and the spot on the inner fender where it connected to the rest of the wiring harness, then reassembled everything with new nuts and washers and lock washers and the problem has never returned. I still have the other stalling issue on initial startup but I think I'm closing in on it.

No chance it will be my battery terminals. The battery is new and I have disconnected and connected it over and over with no issues.
Right now I am going to wait on the fuel pump, install it, test the car then start another chapter in this stalling saga.

That's what I said. Every other car I can ever remember either had the B+ coming off the starter or molded into the main battery terminal. I never saw one that was nutted to a stud on the terminal before. Boy was I surprised when I finally saw it.

I have never heard/seen this. What does it do exactly?

Have you conducted a proper vacuum test on the vehicle?
A full emissions test? And not from the tail pipe either. From the engine compartment.

Codes are sometimes not thrown. I am not a mercedes mechanic.

Get a pin to pin check on all wires to and from that computer. They can be a culprit.
Good grounding is a must. Everywhere.
Disconnect each connection and inspect for corrosion. Clean and use the clear dielectric stuff from the tube when reconnecting. Every connection you can find.

I am finding connections with corrosion all the time.

It shuts off fuel while coasting with no throttle applied, and tells the system to idle once the engine speed comes down to idle range.

I am of the opinion that taking a Bosch injected vehicle to a dealer or indie is a mugs game. Most of the dealers and indies in my city send the cars with injection problems to a Bosch franchised injection specialist. These guys only do one thing - Bosch injections. They have all the technological equipment and know how - inherently more knowledge than the average mechanic.

A full service, system adjustment, system clean-out, and diagnosis costs around $ 150.00 at the Bosch specialist. He will then inform you of suss items. AND they know exzactly what they are doing.

Haphazardly trying to guess what is going wrong with a KE injection system with a multitude of expensive individual parts can lead to an expense much more than the sum of the problem as indicated at the start of this thread.

At least the professor has replaced do much on the injection system that he should have no real problem for years - caveat - after it is tuned properly with the correct equipment.

Hmm I never thought of that myself. I may actually do what you said and take my wagon in that has idle issues. Thanks Ivan!

Is your problem still the miss at idle?

you may require an adjustment on the throttle plate sensor . the two inserts on the side can be pried out and under it will be 4 screws . mark the orignal position for reference and the adjust about 2 millimeter on the up side then on the lower side .test in each position

hope this will help.
mak
300se

Crap in the fuel tank...

Ouch
 

I am going to assume your issue is fixed.

For others having this nagging issue.

* I suggest you give the throttle body chamber and Idle Air Control Valve a good cleaning.

* The signal to start - run the fuel pump goes through the OVP relay, which has been superseded due to random thermal failure issues.

* The fuel pump relay has on many models been superseded three times due to random thermal failure issues.

* The Crank position sensor can experience thermal failures that match your symptoms.

* Try measuring system voltage, perhaps the charging circuit or battery is so weak that it can't operate the electronics correctly. Failing batteries cause no end of havoc, and the notion that just because it took a charge and started the car must mean that the battery is good is false. Test it to be sure

Here are some rather odd issues that have happened to me many times, and could match your symptoms.

http://www.peachparts.com/shopforum/tech-help/220150-owner-1991-300e-looking-cliff.html

http://www.peachparts.com/shopforum/tech-help/245151-103-stalling-not-starting-when-warm.html

Benzworld.org - Mercedes-Benz Discussion Forum - View Single Post - 190E 2.6: While running/driving, engine "stalls", tach dies, BUT.....

MBWorld.org Forums - View Single Post - Help! My 190E 2.6 keeps stalling when hot!

As a last resort, you can read the Epic Saga "stalling thread", it's over 194 pages long.
Stalling Again - Benzworld.org - Mercedes-Benz Discussion Forum



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