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      06-01-2016, 04:05 PM   #7
BMWrules7
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Drives: 2015, 740 LdX, Alpine White
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Quote:
Originally Posted by Barbera335
Quote:
Originally Posted by BMWrules7 View Post
The fuel pump starts before the engine ever attempts to start, right? Would not the system lock out the starter motor if the fuel pump had a fault?
Yes, the pump does run before the engine starts. And unfortunately, because the pump is still functioning while self destructing the computer will not turn it off. Unfortunately the pump is sending metal shavings along with fuel up to the engine while the engine is trying to start. This is what destroys the high pressure fuel pump, injectors, etc. Your dealer should be replacing the entire fuel system.
Ok, thank you so much for your advice.

I discovered another reason BMW does not disable the starter if the fuel pump subsystems fail: In order to place vehicle in Neutral when motor fails to start!

This boneheaded idiotic procedure is overly complicated and extremely hazardous.

You need to depress start button while foot on brake, shift and hold selector release while shifting into N. Then release, and shift back into neutral (while holding selector button) within six seconds.

This procedure requires a fully charged battery. If the starter gets hot or the battery depletes and the starter motor short cycles (I.e., cuts out prematurely) then the bloody car will suddenly shift back into park. By ensuring the starter has enough juice for a full cycle, the system knows it has enough power to manage the shift out of park into neutral. The uninitiated will find this procedure to be disturbingly challenging.

I guess if you strike something that causes the air bags to go off, the battery pyrotechnic charge is going to blow power to the starter motor. Thus, after such an accident you will need some other procedure to put the car in Neutral. This sucks because minor accidents involving the air bag (if there is such a thing) will make it hard to put this car in neutral. That can only mean than an impatient or inappropriately equipped tow truck operator is going to do even more damage to your x3 as they winch the car on the flatbed whilst the x3 remains in park.... I can hear those tires rubbing now!
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