1991 BMW Other Crank won't start

CAITLINBAILLARGEON

MEMBER
1991 BMW
MANUAL
126 MILES

I have an e30 and it cranks but won't start. I replaced the fuel pump, relay, battery and we bypassed the fuel pump to the battery and it started. Why can be the problem that the bypass worked but it won't work without?
126,000 miles

Sunday, August 31st, 2014 AT 10:10 AM

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,772 POSTS

Either you have no power from the relay or there is an open in the power supply to the pump.

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Wednesday, September 3rd, 2014 AT 5:13 AM

CAITLINBAILLARGEON

MEMBER
2 POSTS

How would I check for that? And where can I find a fuel pump wiring diagram? I've been searching online and can't find any for my year

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Friday, September 5th, 2014 AT 7:52 PM

JACOBANDNICKOLAS

MECHANIC
109,772 POSTS

I would first check if there is power to the fuel pump relay. If there is, I hate to say it, but you need to access the wiring to the pump which, if I remember correctly, it above the fuel tank. You need to check if there is from the power supply getting to the pump.

As far as a wiring schematic, most likely I have one I can access, but it is impossible to copy and paste. Also, I would need the model of the vehicle. From that, I can try to walk you through it. Other than that, I would purchase a manual from the parts store for you exact vehicle. They may have to order it, but it would be helpful if you like to work on it yourself.

Let me know.

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Friday, September 5th, 2014 AT 8:24 PM