OK. Here we go, I am trying to diagnoise a friends, friend car without seeing it..
It is a 1992 190E Gas/petrol 2.6 runs for intermittent periods then dies and won't start. let cold soak/ sit awhile, about a few hours and it restarts.
They had fuel pressure checked when it was not starting and it had pressure.
To me it sounds like a classic ignition system electronic componet failure.
Is there a crank angle sensor on these cars? I know it has the distributor on the very front of motor. Located at end of cam. I don't think that distributor has a hall switch to tell coil when to fire, once again I think theres a C.P.S. sensor??
I know Mercedes pretty well and kinda remember the last one of these I worked on but I have slept since then..
I don't have any books or tech sheets on this one, anyone know this ignition system by heart??
All help appreciated!

 

Dumokie,

Yes there is a crankshaft position sensor in the back near the fire-wall, toward the drivers side. The wire from the CSP goes to the EZL unit located on the driver's side fender/bulkhead.

You can test it with an analog ohm meter, by leaving the CSP installed in the car, unplugging its plug from the EZL unit, set the meter to OHM, contacting the meter probes to the two contacts inside the plug, then have someone crank the engine over a few times. If the CSP is "picking -up", you will see the meter needle twitch once per rotation, indicating that it is working.

Blue

 

Hi, i have a 1990 190E 2.6 and had the same problem. I was sure it was a fuel problem as i have had a few with the motor. When it got hot it stopped, had no power, would not draw away in auto D or R and very often would not start again at all. If it was left to get absolute cold , it would start and run like a dream.
The fault in the end was the distributor cap and rotor arm, the arm had cracked across one of the 3 mounting points and had broke off the center conductor in the distributor cap. All the 6 contact points in the cap were black crusty and mouldy and the center of the cap was all burnt and blistered. Replaced , now seems to run like a dream again.
Just a thought!
Mawbs.

 

Mawbs!
Hi mate.
The scary thing is that MOST of the FI parts can develop some kind of glitchy "now I work, now I don't" condition. I think this is what frustrates everyone because it challenges our logic. I'm going to go check my cap now.

Blue