1995 Mercedes S500

I am going through the same. I will keep you posted on my progress

Thank You

It seems according to all the research I have done that the ignition control module is the culprit. Now, legend says (can’t confirm this) that a bad voltage regulator and the use of non-oem spark plugs can cause this. OEM spark plugs are non-resistor which makes a lot of sense. On eBay the sparks can cost $36 for all 8 and the regulator about $49. The trick comes with the ignition control module. You must match the numbers or get the interchangeable ones. Mine went for approximately $230 plus shipping. Seller gives a 6 warranty. This module is located behind the driver-side headlight under the plastic cover. Get me the number or a photo and I will help you find the correct one.

Ignition control module price is for used one.

I will replace spark plugs, regulator and ignition control module at the same time.

Spark plugs on eBay. Item 303140923407. Voltage regulator on eBay. Item 142380204516 and ignition control module (this is mine and may not be the same in your car) on eBay. Item 192787592048. The descriptions are very informative to understand what causes the problem. There are other possible causes but in my case it is pointing to the ignition control module.

I had this same problem with my 1980 280 E, which was basically a 2.8 hemi 6. GREAT car that I inherited from my late grandmothers death. here's the issue. JJs 500 the plugs /wires have NOTHING to do with it because the car already was operated for about 15 minutes, right? really not trying to be rude here. when you open the car, look for a black little box by the firewall ( it might be different for later model cars). That relay box was old on my car and I had to replace it ( I took a risk on a part from a junk yard and used it). The stalling after a few minutes stopped. The part was either old, or it decided to quite working around the heat. Heat and electronics DON'T mix on either genre vehicle. Look in your owners manual to find out where it is. IF you cannot find it, go to a shop or even a dealer. They will be MORE than happy to show where it is BUT they will expect you to buy one from there. don't .. just go to a junk yard where there are several relay for a buck or 2

That happened in a 1994 xj40 jaguar that I have. Problem solved. But compared to my other two w126 s-class the w140 is a precision computer on wheels. This problem started after the spark plugs were replaced. Mercedes m119 engine uses non-resistor spark plugs and I just installed regular ones. The ignition control module stops sending voltage to one bank hence the stalling. This car has computers that monitor computers! It’s insane. I have the s320 and the s500. I really like them! Well, not as much as the DeLorean but getting there! Thanks for the advice. I will try to find the part you say on this car.

New insight: fuel pump may be getting hot after 15-20 minutes and it shuts off. Known issue for some w140 Mercedes-Benz.

Latest update: Fuel pump was fine and was not replaced and neither the relays were replaced. New non-resistor spark plugs were installed with 1mm or 0.04 gap. New voltage regulator installed (no need but I wanted to) and ignition control module (used off eBay) was installed. Car left with engine running for a little over 3 hours without any issues at all. Temp was always around 80 degrees Celsius.

As advised by MB mechanics, the use of regular spark plugs on m119 engines would work for some time at the expense of damaging the ignition control module, hence why people can’t match the damage to the spark plugs. Mercedes designed it that way and that is the reason why so many w140 are being scrapped. Lack of proper maintenance is the culprit. He also advised to just do some research and also advised never to compare s-class maintenance with the rest of the Mercedes models. The sonderklasse or “class on its own” as he describes it , means exactly that, no other like it. My friends have c-class and e-class and it accepts virtually any parts. The s-class is precisely a car that took 1 billion dollars in research and development back in the 80’s to begin production in 1991. It’s the las over engineered car in history. They tried virtually all possible scenarios and decided which was the best, included the spark plugs available at that time. No wonder they would cost more than a house back then (no bathroom included). The sticker price on mine was $115,000 back in 1995. I got it for $2,500 with 38k miles. I am learning this baby every single day and it’s awesome

Mileage

S500 with modified emblem (60s Chrysler Imperial). This is the one it has 90% of the time.

S500 with modified emblem (60s Chrysler Imperial). This is the one it has 90% of the time. The other is the Rolls-Royce emblem/mascot. Only take her out on long trips.

By the way, both emblems/mascots are OEM ones. I just bought a few OEM MB emblems and removed the top part. Replacing them takes only minutes but the Rolls-Royce (Spirit of Ecstasy) is so heavy that I do not open the hood completely. If it slips out of the hands it will smash the windshield.

18” wheels from 2007 s-class

AMG tailpipe

GuruSX58C, by the way, you can call me JJ. Since replacing the spark plugs is considered regular maintenance, I would replace them as well as the ignition control module. Now, can you post a photo of your ignition control module? The numbers have to match yours or the equivalent ones. In my specific case it gave 3-4 additional options to the same one I had. Another modification I installed on this car is a simple one that requires a part from the s-class w126 series. It allows the car to start every single time in first gear rather than the 2nd gear that your car and mine starts with. This was later improved with the S/W switch that basically means “Summer/Winter”. In summer it starts in 1st gear and in winter it will start in 2nd gear to avoid slipping. You can research w140 first gear start. You will find many links to it. It is a short gear when driving slowly but it is amazing long when driving 0- 60 entering the highway! I’m not sure if you know this but the W140 vehicles are designed not to change into the following gear until the catalytic converters get into operating temperature thus getting the car into emissions-ready status faster. It is not a transmission problem but yet another over engineered feature of the w140 series. Just let the engine warm before driving (when started cold) and problem solved.

Here