Jump Starting
Moderator: martauto
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ChrisHC
- E30Zone Contributor
- Posts: 515
- Joined: Fri Oct 23, 2015 11:00 pm
Arising from the topic of the blown ABS ECU, is there a safe way of jump starting another car from an E30, or correspondingly jump starting an E30 from another car?
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martauto
- E30 Zone Team Member

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- Joined: Wed Aug 31, 2005 11:00 pm
- Location: leeds
Forgive my ignorance but why should there be a problem ?
Brian ???
Mart.
Brian ???
Mart.
Only the E46 cab left now.
Just got too old.
Just got too old.
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ChrisHC
- E30Zone Contributor
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- Joined: Fri Oct 23, 2015 11:00 pm
Voltage spikes frying electronics
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paultv
- E30 Zone Squatter

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It's suggested that even when fast charging a battery, it is advisable to remove a number of fuses to protect the computers in the car. Burning out the zener diode in the ABS relay is pretty common when jumping the car - maybe wise to remove the ABS relay, get the car running and replace the relay when the car is in "stand alone" mode.
Paul
Paul
4th May 1990 325i Convertible.
BMW E30 Cabriolet Best Mod Ever:
https://bmwe30cabriolet-wdm.blogspot.com/
BMW E30 Cabriolet Best Mod Ever:
https://bmwe30cabriolet-wdm.blogspot.com/
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PattheCat
- E30 Zone Newbie

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- Joined: Fri Mar 02, 2018 11:00 pm
As someone who has recently fried their ECU relay through a jump start, I would recommend removing the battery and connecting to a trickle charge overnight
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ChrisHC
- E30Zone Contributor
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- Joined: Fri Oct 23, 2015 11:00 pm
Surely a trickle charger is not going to cause a problem? It never has on mine. When fast charging or jump starting, disconnecting the battery leads should protect the electronics in the car, at the cost of having to reset the clock, admittedly.
I was wondering if there was anything even easier, many people for instance will tell you to have the engine running, does that do anything to avoid voltage spikes?
I was wondering if there was anything even easier, many people for instance will tell you to have the engine running, does that do anything to avoid voltage spikes?
