Car stops randomly, but not often.
 

My car will sometimes randomly shut off. So far it has happened 3 times. Once as I was driving about 20 mph, the car lost power and dash lights lit up and I was able to drift to the spider of the road and restart car. Another time I was on the freeway sitting in traffic and the car engine cut off, I put the car in neutral and restarted it. Another time I was just sitting in my driveway, car in D, but I wasn't moving and the engine shut off. The last time it happened I was reversing out of my driveway and as I began to turn the wheel it shut off. I did notice that my car idles high sometimes and sometimes its fine. I checked the ovp and both fuses are fine. I also checked the voltage regulator visually by taking it out of the alternator and it seems fine. Any suggestions?

I had the same thing happening in my '97 CL500. We checked the codes and it said the MAF was defective! We pulled it, cleaned it but the problem remained. $320 later with a new MAF the problem disappeared along with the error code. Go figure!
Anziani
'95 E420 130K
'97 CL500 135K

What year?

Fuel pump relay?

CPS? (don't know if it even has one of those)

+1

Need to know more details than just "190E 2.6" because the fuel pump relay changed during the later models.

Could be any: OVP, FPR, low compression, CPS, MAS, etc.

1990

Check your alterntor properly, get your dvm and place it on the battery, start her and get a friend to rev and keep the rpms at 2500, you should have a steady 13.8-14.2 volts. After that have friend turn all electronics on full, it should still bein the range.

Before, what is the voltage before start? If below 12.8, the battery is drained.

Jim

Maybe you can learn a thing or two from Drew's novel

Stalling Again - Benzworld.org - Mercedes-Benz Discussion Forum

The way it stalls & restarts suggests an issue with the "air flow position sensor".

A new MAF solved it for me. See Post #2 above.
Anziani

Is that the mechanical predecessor to the MAF or something different?

Replace OVP -it fails
 

If you do not know the history of the OVP, replace it. Cheap insurance as they say.

The fuses may be "good", but an OVP fills up with dirt, or corrodes over time, or solder fails, or all.

ovp replaced 7/9/10

I think around 90 they moved to the MAS relay for fuel pump power however on my 89 420SEL the fuel pump relay had a cold solder joint on the fuel pump relay which would cause the fuel pump to randomly get turned off.

On my 190E I had a simliar problem with the car turning off randomly. It turned out to be both bad spark plug wires and bad OVP solder joints. I resoldered the OVP and it has been fine ever since.

http://www.peachparts.com/shopforum/tech-help/339278-420sel-randomly-stalling.html

It could be the crankshaft position sensor ckp. You can replace another one yourself. My car used to crank but wouldnot start and after i replaced it, starts all the time after. It also stalls sometimes while driving.