Help.. Rough idle - Benzworld.org

Guest (MBNZ) · 06-21-2001, 02:53 PM

Has anyone had this problem or experience?? 
 
I have an older model 300CE that recently had a valve overhaul. The perfomance was ill at first (sluggish off-line), but now better, with the execption of two things: 
 
1) occational rough idle during stand stills (i.e. at stop lights); and 
2) occational difficulties in starting - engine turns over but does not engage. 
 
My mechanic replaced an electric module, which cured the sputtering starts off-line, but the rough idle and occational starting problems still exists. Lately, he replaced the fuel modulator, it helped but not an all cure. He's thinking maybe the fuel pump (he'll replace next visit). We're still scratching our heads. Any insight would be appreciated...

Guest (MBNZ) · 06-22-2001, 09:26 AM

I too have the same problems with my 260E. Please let me know what you find out. Tommy

Guest (MBNZ) · 07-05-2001, 02:12 PM

I have the same exact problem with my 260E. Its a 1989 and i had the fuel relay switch replaced to try to fix it. It did somewhat, but now its getting to the point where its about to stall because it idles at very low RPM's (500 RPM idles). If you find the problem, let me know. thanks

Guest (MBNZ) · 07-07-2001, 07:55 AM

I have low idle on my '92 300E. It was cutting out when hot because of the low idle. It improved when I unplugged the idle air valve. I figure in my case the idle air valve is jamming when hot. I await the arrival of a replacement.....

Guest (MBNZ) · 07-09-2001, 07:02 AM

O.K. I think the car is finally fixed (got my fingers crossed). I will know for certain in a week or two of daily driving. As it turns out, my 88 CE has two fuel pumps (surprise!). Apparently at least one was faulty, hence explaining why it seemed like it was runing on only two cylinders starting off line. I just got it back from my mechanic a couple of days ago. The performance seems great (lots of spunk), the rough idle appears to have diminished (though not perfectly smooth yet?), and the starts seems o.k. But, I need to take it on a long highway drive to really know that all is fixed. As of now, it seems to be all o.k.