Very balky 300SL

[Robert Deming]

My 1991 300 SL (M104 engine) virtually stalls when I try to accelerate during warmup. It starts well and runs fine for about five minutes. Then it continues to idle well, but will not accept much increase in throttle opening. If I try to open the throttle, the engine stalls and is very hard to restart. After a LONG warmup, 15-20 minutes, it runs OK again.

I have done all the tests I can do with a multimeter. The throttle switch is OK, the throttle position sensor seems to work, the airflow sensor works. There is continuity to the EHA. The only thing I find wrong is that the duty cycle measured at the test connector does not vary with the airflow sensor position. The test procedure I have seems to make the airflow sensor/duty factor test an alternate to the throttle position/duty factor test, and that works fine. So I don't know if I have a failure or not.

I sure will appreciate the advice of anyone with CIS-E experience.

Bob D.