The most confusing thing I have ever witnessed on a car!

[jack_davey]

Working for a breakdown recovery firm at the moment and I went out to this woman in an E36 BMW 3 series.

Symptoms were wouldnt start, turned over.
The woman told me it would start if I put my jump pack on it.
I immediately stated the obvious and said:
"well if it's turning over it's obviously got plenty of charge in the battery"

She then said: "I know, it sounds stupid, but it's done it before and it worked when the last guy jump started it"

I thought to myself there was no harm in trying, so put the jump pack on it and sure enough it fired up!
Got the battery tester on the battery and it was all good!

Can't understand it at all though! :S

Anyone else experienced anything like it?

 

[adam172]

needs a bigger battary ?? maybe not sure

 

[Hutchie]

had a few bmw's having a faulty starter, they draw too much current on cracking, having the jumper pack on will stop the voltage dropping below 10 on cranking.

last one we did, had a wagon sized battery on and sounded flat, when we checked it, voltage was dropping down to 7.6 volts on cracking :O

 

[jack_davey]

^makes sense but this was cranking over nice and quickly like there was no battery issues at all

 

[Moose4624]

My Pajero used to do this, would just whine like there was no power, the moment it had jump leads or a jump pack connected, started first time every time, and that thing had 2 batteries!

 

[jack_davey]

^Yeah went out to one of those the other day, had recently been for a service and one of the batteries was removed and just had the leads tucked out of the way! Brilliant!

I still cant work out this BMW though, makes me feel like I know nothing! lol!

 

[gaz_5103]

id say its probably a duff battery. just not getting the voltage to start. try a new battery in it. ive had this before, but not on a BM.

 

[sideways danny]

enough battery for cranking but not spark

 

[jack_davey]

Tested the battery and it seemed fine, in hindsight I should've put a spark tester on there to cure my curiosity, but just couldn't be arsed taking the covers off and unbolting all the coil packs

 

[sophiesdad]

yes seen this few times before , needs slighly bigger battery .
also she shouldnt keep jumping in case of surging and blowing components/

 

[stevo172-RWD]

Like danny says if cranking voltage drops too low
and then no volts for coil to charge and spark at plugs?