PeachParts Mercedes-Benz Forum - '80 300se start,stall,start,stall,start,stall

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Update. Return of the problem, sort of . . .

After several weeks of working fine I had a return of the problem. I've been making sure that the AC is off when I start the car, as that seemed to help when I was in the midst of tracking down the cause of the start/stall/start/chug-chug/run behavior. However, last week I forgot to leave it off and the problem returned. I was in a hurry, so I held the gas down, which made it start right up again, but it would stall as soon as I took my foot off. It even stalled a couple more times as I was coming to, a stop.

After that the idle seemed to drop down to a slower speed than usual, and it would cough and shudder a couple of times, though it didn't stall.

I decided to try my spare OVP again. I tried it when the problem was at its height but it made no change. Now that the other problems are cured, it did make a difference. It's been about a week since I put it in, and the problem has not happened again. Also, I've been starting it with the AC on to see if I can force it to fail. So far, so good.

One more update.

No return of the problem, but I decided a new fuel pump relay was in order and put one in. Now the car cranks about 1 second longer before it fires, but the revs never drop down as though it's going to stall after it does. They stay up there in the correct range for a warming engine, then slowly ease down until it's idling smoothly and at the right speed.

Of all the testing and changing of parts that I did, it seems the only ones that made a real difference are:

New Injectors
New (used) OVP
New Fuel Pump relay
New O2 Sensor

I'm glad I replaced the rest:

Distributor Cap
Rotor
Ignition Wires
Spark Plugs
Crank Position Sensor
Spark plugs
Fuel pump
Fuel filter
Fuel accumulator
Hoses leading to and from the ICV
All fuses
Air filter
Coolant Temp Sensor
Throttle Position Microswitch

As I now know what the state of the car's maintenance is.

Along the way I also aquired a spare EZL & ECU. Both tested and working fine.

It's been a long process, but the car is now boringly reliable. I just turn the key, put it in gear and drive away. At one point during my quest, fuel milage dropped to a little over 14 mpg now it's consistantly 19.5 to 22.2.

replace coolant temperature sensor