1989 420 SEL Stalling update
 

While driving home my car began to run rough and hesitate as if it wanted to stall. The RPM gage was moving rapidly out of control. I managed to get the car home and it stalled. It will start but stalls after a few minutes. I had it towed to a European repair shop and this is my diagnosis thus far, and the car still stalls.

Crank position module replaced
Ignition control module replaced (That was a fortune.)

I'm at my wits end with this car. Luckily I found a used ignition module. So far the bill total is up to 1160.00.

I will keep everyone updated. I should know more in a few days.

Does anyone know a repair shop or specialist in Southeast Michigan?

Mary

Try John & Holger..
 

You can try a place called "John & Holger".. it's in an eastern suburb of Detroit (can't remember which one.. maybe Hamtramck?)

They're pretty good.

If you are in Detroit and want to make a 4hr trip to Toronto, I can suggest a guy who is GUARANTEED to fix it. He's a former MB tech and *really* knows his stuff. He knows the W126's like the back of his hand... has certainly solved a number of "unsolveable" issues with my cars.

Neal

rule out the fuel pump relay
 

Install temporary jumper between socket pins 7 and 8 of the fuel pump relay and see if you problems disappear. If so its the relay. Remember, while the jumper is installed the car will always be pumping fuel--remove jumper when not in use.

So what happened?
 

Well did they solve the issue... I know I am late in posting this but I have the same issue

1986 420 SEL

Mary dose the car just stall or dose it do it when dropping in rpm such as coming to a stop sign?

I solved it
 

I solved this problem...
Changed idle air control valve, changed plugs to Bosch Copper Core, all my ignition wires, cap ,rotor, coil and grounding wire... Runs like new. this is a idle air control valve (replace or clean out... including electrical contacts) problem mixed with the fact that original ignition equipment is on the car. Bad ignition causes a cascading effect in the system. Also not that the brittle vacuum hose that runs from the Ignition control Mod located on the driver's fender to the drivers side of the engine (yellowish) can be cracked. Mine was.. Then there is a vacuum hose at the front of the engine that runs down from a black and blue vacuum diaphram near the distibuter that runs down deep inside the block, this heats up and falls off, long pliers will fix this... I think its a yellow and red tube 15cm long. All this will make a difference... Ignition system replacement was the best thing I ever did... only use Bosch copper core. oh get only Bosch equipement, its not GM, this stuff is all top of the line.