Hopefully someone can point me in the right direction. I've searched through the archives, and found several leads, but no answers.

I have a '92 190e 2.6 with just shy of 250K. The car had been running normally, but on a drive several weeks ago it began to stumble when I came to a stop at an intersection. Thankfully I was able to go the additional two blocks to my destination without any problem. I came out to start the car 10-15 minutes later and it would not start. The engine turned over as normal, but it would not start. I left the car and came back 4-5 hours later. It started as normal and I drove it home (7 miles away) without any problem.

Once home I tried to restart the car after it sat for a few minutes and once again it would not start.

I pulled the cap and rotor which are about a year old. There are signs of carbon tracking, but not too bad. The plugs are about the same age, and appear to be in ok shape, but it appears the car has been running a bit on the rich side as they were all a bit black. I cleaned them as best I could with some brake cleaner and reinstalled.

A day later I started the car without any problem, but it died after about a mile and would not start. I came back later that day started the car and drove it home again. Since I've had the car back home it now will not start.

Initially I thought it might be the coolant temp sensor. They're fairly cheap so I replaced it, but that caused no change.

It appears to have a weak yellow spark at the plugs. I swapped in a used coil and get the same quality of spark. It acts as if it wants to start, but almost seems as if the timing is way off as it has backfired while trying to start. Voltage at the coil is just shy of 12v. I read 11.8v which might be due to the battery getting slightly drained by all the attempts to start the engine.

I tried spraying carb cleaner down the throttle plate to see if the problem is fuel, but this had no effect.

I pulled the connector for the crank position sensor from the ignition module. Not really knowing how to test it I just used an ohm meter to see if there was any change when the engine was cranked. It does fluctuate, so I'm assuming that's okay.

I've seen many threads talking about cracked vacuum lines in M103 engines. I am not finding anything obvious here either.

Any other suggestions are greatly appreciated.

Thanks,
Dean