1984 BMW 733I
145,000 MILES
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1984E23
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While driving down the road the engine suddenly stops running. Each time I try to start the engine runs for 1 or 2 seconds and the stops again. After several tries the engine keeps running. I have noticed that after the car has been running for a while and I stop the RPM fluctuates up and down. The engine suddenly stopping is comming more and more frequently.
Thank you,
Ray.
Dec 18, 2012 at 4:02 PM
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MERLIN2021
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Check fuel pressure.
Dec 18, 2012 at 4:52 PM
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1984E23
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The fuel pressure is fine. We also recently changed the fuel filter. I think it is something electrical. This BMW has alot of electrical components, I probably need a response from someone that is familiar with older BMW's and familiar with the electrical components and which one would cause these symptoms.
Dec 19, 2012 at 1:06 AM
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MERLIN2021
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Does it only happen on deacceleration and idle? Or all the time?
Dec 19, 2012 at 8:33 AM
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1984E23
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It happens mostly at in town speeds and idle. Generally runs fine at highway speeds.
Dec 20, 2012 at 12:30 AM
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MERLIN2021
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Have you checked throttle body, and IAC? Clean all ports of carbon? And PVC system is a biggie, dry rot of vacuum hoses and PCV gasket.
Dec 20, 2012 at 8:42 AM
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DOCHAGERTY
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I agree with Merlin. The items on his list need to be checked and eliminated from the equation. I also have some input as to the idle air control, it is usually quite robust on that car and I have not seen them fail, however, diagnosis of that system would start with checking for power at the IAC valve/connector and resistance at the IAC valve. With the key on and the engine off, the valve should be felt to vibrate, if not, you have a problem with the IAC, let us know what you come up against mate.
Dec 29, 2012 at 11:45 PM