1987 260E stumbles and stalls after warming up (after sitting over weekend) - Page 2 - PeachParts Mercedes-Benz Forum

skis3 · #16 10-05-2011, 01:28 PM

It is at least 80% highway averaging 65-72 mph. I will be thrilled if I can get 22 mpg.

Mike Murrell · #17 10-10-2011, 01:15 AM

Does this occur only after driving approx. 15 or so miles in warm weather....guessing it's still warm where you live.

If so - suspect fuel pump.

skis3 · #18 11-03-2011, 09:58 AM

My fuel economy has finally reached 23mpg averaging 75mph. The car still had trouble starting on two occasions after changing the O2 sensor and OVP. I tested the resistance on the crank position sensor and the values ranged from 830-2350 ohms. The specification was 600-1300 ohms, so I changed the sensor and now it is running and starting much better. I know several people said to change the sensor, but I did not want to change the sensor before performing some sort of verification test. Now I am working on vacuum leaks. Thanks, Bob.

lorainfurniture · #19 11-03-2011, 10:36 AM

Quote:

Originally Posted by skis3

The mileage has gone from 16 to 21.5 and I hope it will go a little higher after I adjusted the duty cycle from 10.8 volts to 6.2 volts.

What did you do to adjust your duty cycle? Did you adjust through the eha?

skis3 · #20 11-03-2011, 11:22 AM

I used a multimeter and measured the voltage across I believe pins 2 and 3 in the circle port on the driver's side of the engine bay. The engine needs to be at normal operating temperature, then you use a 3mm hex wrench to change the duty cycle. Insert the wrench in the hole of the air filter cover, push down and turn screw to change the voltage. I revved the engine after adjusting the duty cycle to see if the value was stable. There are several good articles on the subject if you search the threads.

KenCBrown · #21 03-10-2012, 05:02 PM

This is a most helpful thread. I too have a 1987 260E which is exhibiting similar symptoms: my car won't restart after being turned-off once reaching temperature. it cranks and cranks and I detect some backfiring (too advanced ignition?) and it will not light. Could it be a bad crank sensor in my particular case? Should I also consider the O2 sensor? -Thanks!