2000 2.3 automatic trans.
On occasion- when warming up- I get a rough idle. "feels" like it would be a vacuum leak or timing off. (if it were a 1960's american car)
Today it did it after running about 1 min. Noticed it as I pulled up to my front gate and put it into park to get out and open the gate.
After I noticed it---- as an experiment--- I shut it off and restarted the engine. It was completely
gone when it started back up. Did not re-appear. It has done this 3 or 4 times in the last 3 months.
I got a schwaben code reader a little while back. I have been checking for codes each time I come home from driving.
I have gotten lean mixture codes a couple times-
got a cyl. 6 misfire code 2 days ago.
(neither of which have reappeared)
So tonight I thought I would take a scan for codes to see if that rough idle this morning recorded any codes. No engine codes. No tranny codes.
(dont have the other cable yet to do other modules)
So im asking myself--- what type of problem would cause rough idle but not generate a code of some kind ?
Could it be something really basic like the oil is a little dirty and Mr. Vanos is failing to return to home at idle ? (and when I shut it off and
restarted - that cycled the oil pressure and helped it reset to home ?) Should I try changing the oil a couple times to get it cleaner in there ?
It has 116K miles--- Ive only owned it about 6 months--(driving it for 2) ---- no idea if the vanos has been updated with the new O-rings-
The manual with the Schwabben is so large I havnt had time to dig into it yet to understand all it can do...... AND- this is my first scanner too....
Suggestions ?
Tim
Last edited by fairchild; 09-22-2017 at 10:16 PM.
That actually is one of the symptoms of a worn VANOS seal on the M52TU/M54 engine. I spent a weekend as a guest of Raj a few years back. Fascinating conversations, one of which was about his old E46 and spending years tracking down a rough cold idle. In a nutshell, after figuring out the issue, he handed the info to BMW. They didn't care; it was an old product at that point. So Beisan Systems was born.
Anyway, a lean condition can cause your symptoms. The computer is correcting for a mixture issue, and overshoots cold. What code did you have?
A misfire can also cause your issue. If the computer detects an issue, it will shut down the effected cylinder totally. Restarting the car will reset the system. Again, what code did you have? Code numbers matter. Vague paraphrases of a vague imperfect description that's been through a german-english translation can only get you a vague answer, at best. We need the number.
/.randy
I would have a slight miss at idle when cold once in a while and then one day a mile from my house I had a coil fail. It was trying to warn me but I didn't listen .
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