No power to coil

russhixmo · 03-27-2012, 12:21 PM

Have an b34 motor that im swapping into my 83 533i and i know the motor runs strong because it was running a few weeks ago but I let the car sit and went to go start it recently and it cranks all day but not start. Figured out there's no power to the coil but not sure why. Any thought?

k.gen04 · 05-31-2012, 05:15 AM

First check the 12v side of the coil by connecting a multimeter between it and ground. Should be over 10v there when the key is in the on position. If not, you needa check your wiring, as according to my e34 ETM it goes straight back to the ignition switch.

If it does have voltage at the 12v side, disconnect the 12v lead and check the resistance between the ground side of the coil and pin 1 of the ECU. If all good, next bet would be the CPS probably, check the gap. Also be worth checking your ECU connector pins too.

03-27-2012, 12:21 PM	#1
russhixmo Grease Monkey Join Date: Jun 2011 Location: East Haven CT Posts: 337	No power to coil Have an b34 motor that im swapping into my 83 533i and i know the motor runs strong because it was running a few weeks ago but I let the car sit and went to go start it recently and it cranks all day but not start. Figured out there's no power to the coil but not sure why. Any thought?

05-31-2012, 05:15 AM	#2
k.gen04 Noobie Join Date: Apr 2012 Location: New Zealand Posts: 33	First check the 12v side of the coil by connecting a multimeter between it and ground. Should be over 10v there when the key is in the on position. If not, you needa check your wiring, as according to my e34 ETM it goes straight back to the ignition switch. If it does have voltage at the 12v side, disconnect the 12v lead and check the resistance between the ground side of the coil and pin 1 of the ECU. If all good, next bet would be the CPS probably, check the gap. Also be worth checking your ECU connector pins too.