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The fuel pump, main relay and fuel system relay, even the DME.

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I have a 94 530...
I have a 94 530 that i just cant get to start. Replaced the fuel pump, main relay and fuel system relay, even the DME. Turn the engine over and still no power to fuel pump. Can anyone enlighten me with anymore information? Frustration starting to set in and am not making any headway. If I jump the main relay and the fuel system relay I traced the wires and found the fuel system relay power going to the DME but it will not send power to the pump. Will the crank position sensor if bad, completly disable the system? Thats the only thing thats left. Looked for broken wires all night and found nothing. Can someone help me out please? Where can I find a wiring schematic. Need to know where the grounds are. Any help would be greatly appreciated.
Submitted: 8 years ago.Category: BMW
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Answered in 5 minutes by:
6/24/2010
BMW Mechanic: Steve, BMW Expert replied 8 years ago
Steve
Steve, BMW Expert
Category: BMW
Satisfied Customers: 26,100
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Hi,

Have you tried using quick start to see if you have spark?

Steve

 

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Customer reply replied 8 years ago
I haven't. My brother and I have been tag teaming this project. What else would cause it not to get spark? Replaced the DME. and the DME also controls the fuel also correct? But to answer your question no I haven't checked for spark.
BMW Mechanic: Steve, BMW Expert replied 8 years ago

The DME will not send power to the fuel pump unless it senses proper ignition, rpm and injector pulse.

 

I suspect this is a bad crank sensor. If you test with quick start and the engine does not catch at all, then you have no spark and most likely it is indeed the crank sensor.

 

If you have injector pulse and spark and the pump is still not getting power, then you might have a dme issue.

 

The quick start test is pretty easy. Also, a new crank sensor is only about $60 so it is not an expensive replacement either if you just want to swap a new one it. It isn't uncommon for them to fail.

 

Please let me know if you have any further questions. Please press the accept button if satisfied with my assistance so that I am compensated for my time and effort. I am not compensated until you press accept.

 

Cheers,

 

Steve

 

 

Steve
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Customer reply replied 8 years ago
But I already replaced the DME with one from a running car. How does the crank sensor tell the pump to prime the system when the key is turned before you try to start?
Customer reply replied 8 years ago
Can the keyless entry system disable that also? When I disconnected the battery and reconnected it my flashers came on as well.
BMW Mechanic: Steve, BMW Expert replied 8 years ago
I believe on your vehicle the prime signal comes directly from the dme. this could indicate a wiring issue if it is not sending this signal
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Customer reply replied 8 years ago
What's the proper test for crank sensor
BMW Mechanic: Steve, BMW Expert replied 8 years ago
Can I have the last 7 digits of your vin please?
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