Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: beachbear on May 09, 2016, 00:45:23

Title: Engine RPM hunting under light load while warming up
Post by: beachbear on May 09, 2016, 00:45:23
Usually experienced after a few minutes of running, while coming to a stop or slowing to round a corner; my '69 automatic "hunts for an idle speed", seeming to die, then surging in waves of unnerving bucks. If I move the shifter to 3rd as I decelerate, I can usually avoid this as I force the engine to assist in braking the car's speed. I have almost no trouble starting the motor. I do usually have to give it a couple of seconds on a "first of the day crank", then rotate the ignition switch OFF and back, but then it starts and runs smoothly. But I believe this is a separate, and less annoying issue. I live in a warm climate, so the engine coolant starts around 72 degrees F. After about 5-10 miles of average city driving, the engine and transmission work together as they should. I've looked at the various components that assist warmup, and shifting, but none seem to relate directly to this issue. Have any of you experienced and/or solved something like this?
Title: Re: Engine RPM hunting under light load while warming up
Post by: Benz Dr. on May 09, 2016, 01:00:37
Kind of sounds like a fuel mixture problem or a possible throttle position switch adjustment or even both.
Title: Re: Engine RPM hunting under light load while warming up
Post by: Cees Klumper on May 09, 2016, 16:32:20
My wngine started doing the exact same thing years ago, and I've been battling it ever since. I am pretty sure it's the WRD (Won't Run Device, aka Warm Running Device) operation, shims, thermostat or what have you. Am going to remedy for sure this summer!