BMW Repair: Low engine rpm on warm start and raw fuel odor, mass airflow meter, intake leak

Question
Recent purchase of a BMW 2002 330CI with 55k mileage and an automatic transmission, has resulted in a perplexing problem. After the engine reaches operating temperature and is shut down, on restarting (warm start) the engine, after say 30 minutes, the rpm is at 500 rpm and too low in Park, resulting in the appearance of the battery icon in red on the instrument panel. The engine rpm even on a “warm start”, which is the condition I’m describing, should be just under a 1,000 I would think and then soon drop to around 650, which seems to be the normal rpm in Park when the engine is warm.

The afore mentioned problem, however, while annoying, isn’t terribly serious, even though it’s obvious something is wrong with the engine. The real problem is the presence of a strong odor of raw fuel whenever this ”low rpm” of the engine occurs on the restart of the engine in a “warm” state.


Answer
John I would look at the idle valve first also the throttle boot at the idle valve bend for cracking and tearing. Could be an issue with the Mass Airflow meter, but not as likely as the idle valve or intake leak. Also check the Crankcase vent valve (PCV) valve under the intake manifold. Make sure this valve is working properly. A torn diaphram in this valve will cause an intake leak and Usually HIGH vacuum in the crankcase.
-Evan