Our E300 can run fine, other times the engine Engine idle always surges
somewhat. At a stop the engine can surge enough the brakes need solid
application to keep the vehicle motionless. Other times the engine will
surge and die when stopped. Much work has been done to correct this
problem, but to no avail. Any help would be greatly appreciated.
Brian, join the club. My '89 does the same...... I've yet to isolate the
problem. It will idle around 500 rpm roughly and then surge (the engine is
trying to correct the rough idle problem) only to stall when coming to a stop
Then there is a, if not literal, 'click' and all will be fine. Clearly the
problem is electrical.... and probably also in yours. There's a plethora of
items to chose from that could cause similar symptoms. I've heard of people
selling their cars for these reasons.
best of luck, guenter
Tiger, interesting. However, wouldn't the symptons (rough running, etc)
get worse at higher rpm....? then there's the 'instantaneous' change in
running characteristics ..... almost like flipping a switch ... when the
engine goes from idling rough and not wanting to rev above 1500 or so (with
the vacuum gauge aka fuel economy gauge, pegged at max) to running perfectly
cheers and thanks, guenter
ps I'm looking for the Hall sensor today hopefully to check
Your perception may be "instantly" because car seems to runs okay until
critical points where cat is really clogged... then it will lead to lower
idle RPM as engne at lower speed has less power to push exhaust out... and
that will lead to rough idling...
As for higher speed, yes, with exhaust partually closed, you can only push
so much CFM out... which at that point engine will not be able to overcome
that and backpressure is high.
Tiger, thanks for that. OK, I will check the Cat. However, meanwhile
I started to disconect sensor to see what the effect is. disconecting the
Temperature sensor from engine made things much worse to the point where engine
would stall out constantly... Then (!) I disconected the O2 sensor (I'm pretty
sure I got it right, it's underneath the mat on passenger side) well (!) all
the sudden no more stalling.... idle still on the rough side, but no more
stalling .... maybe it's just luck but will drive car again tomorrow for some
distance to make sure. I 'may' have found the problem. In retrospect, I did
burn oil (valve stems) for some time which may not have helped the sensor.
Do you think this is possible??
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