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Ron
Ron, ASE Certified Technician
Category: BMW
Satisfied Customers: 33479
Experience:  34 years Fixing Cars and Trucks
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No spark, main relay has power, coik has about 10 v at pin

Customer Question

no spark, main relay has power, coik has about 10 v at pin 15, if I jump the fuel relay you can hear the pump, otherwise not. relay is good.
JA: Tell me a bit more about what's going on so he can help you best. Are you hoping to fix this yourself?
Customer: I can hear the start relay click.
JA: My old Jeep sounds like a steam radiator sometimes. It must be old age. The BMW Mechanic will know what your noise means and what to do about it. Is there anything else the BMW Mechanic should be aware of about your BMW?
Customer: yes, we are trying to fix it ourselves. I have a 91 325i that runs fine. also we switched the crank sensor wires from my 84 745 since those are good to rule that out. but I am just guessing the sensors have the same output as the 325e is supposed to have. . We also checked the flywheel for the magnet. it is there. Also the car had been sometimes randomly not starting but after waiting and trying it would start. maybe unrelated when my son slammed the door the door locks would lock. we switched ecu's and no joy. same behavior.
JA: I'm sending you to a secure page on JustAnswer so you can place the $5 fully refundable deposit now. While you're filling out that form, I'll tell the BMW Mechanic about your situation and connect you two.
Submitted: 9 months ago.
Category: BMW
Expert:  Ron replied 9 months ago.

Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

Can you tell me which year your BMW is as well as engine size and are you saying you are loosing spark? Post back with as much information as you can and I will see if I can help you with this here.

Customer: replied 9 months ago.
its a 1985 325 e, (4 door sedan, e 30) in line 6 cylinder stock engine. approximately 2.5 liters. No spark, no fuel, no fuel pump noise, no injectors firing, battery was charged up. fuel pump relay and main relay have been switched with known good ones, as have the crank position and rpm sensors, the coil and the ecu. When the key is turned on the start relay clicks and there is power to the 30 pin at the main and fuel relays. If I jump those relays ( pin 30 to 87) the fuel pump runs but still no spark. The ecu ends in the number 027. we verified that pin 20 for th fuel pump is functional and drives the pump when grounded.
Expert:  Ron replied 9 months ago.

If the main relay is not powering the ECU you will not get injector pulse, spark or fuel pump action. I have enclosed the steps in the link below to check power in and out of the main relay to the ECU. I would start with rechecking it.

Copy and paste the link below to your browser to open and view the steps.

https://dl.dropboxusercontent.com/u/104923897/Main%20relay%20Mar%2013.pdf

Customer: replied 9 months ago.
We found the problem before doing the checks you recommended on the link.
Expert:  Ron replied 9 months ago.

Glad to hear you got it resolved and thank you as well.

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