Basic question: How to SAFELY jump start ?

[clipper]

I remember reading all kinds of things about fried components due to jump starting E30s in the past, and as I only have a trickle charger which takes about a week to charge an E30 battery I'm going to have to jump my 325 from my E39 this weekend.

How do I do it safely ?

[daimlerman]

Using jump leads is perfectly safe.
I had to start my M50'd touring in this way Christmas Sunday it had stood for 48 hours outside my parents garage in the cold.Dad(aged 86)brought his E46 out of said garage and we connected the leads up.I started my car with his not running so as not to get a voltage surge.
I have now bought a shiny new battery!

[e301988325i]

I believe the early ABS ECU surge protector is most at risk.

I was told to jump start with all the electrics on, lights, blower, radio and heated rearscreen.

[telski789]

2nd gear,clutch down,get 2 people to push it quickly then lift clutch!! tadaaa!

[clipper]

I believe the early ABS ECU surge protector is most at risk.

Not in my car it isn't ! No ABS here.

Thanks for the info to all though, I'll take it all into account.

[murran]

ive jumped 100s of cars. jumper car running, connect the leads earth one last, give it a minute for the jumper car to put a bit of charge in the flat battery. then turn it over. once started, disconnect leads earth first.

put lights and rear demister on? lol, there is some retarded advice on here sometimes!!

[daimlerman]

My theory on having the donor car's engine not running was to prevent a voltage surge that may damage my early type ABS relay.My donor car's battery would have been at no more than 12.8v,going into my battery at around 11.25v,assuming that my alternator was not faulty,there was no way I could get a voltage surge as the engine struck up.
However,IF the donor car's alternator was faulty,running it's engine whilst connected to my battery would have caused a possibly damaging voltage surge.
I have since been able to establish on my iced up street outside my home that my ABS relay is undamaged....

[Brianmoooore]

put lights and rear demister on? lol, there is some retarded advice on here sometimes!!

You reckon?
(willnz,1 : murran,0)

[murran]

i'll carry on my way thanks.
you should alway have the jumper car running to give the maximum boost to the other car. also to avoid buggering up the battery on the jumper car. as soon as you connect up a good battery and a knackard one, it drags all the power out of the good one....... example, you wouldnt just replace one aa battery in you digital camera and expect it to turn on would you?
with it running the alternator on the jumper car almost immediatly compensates for the load your putting on the battery by connecting it to a knackard one. common sence really.


your not guna melt anything or cause damage to components on these old sheds by jumping them.

[murran]

if your that worried about it then pull the relay out! jump it and leave the car ticking over for 20 minutes (to charge it up) turn it off put the relay back in then start it up as normal??????
that would be the non-retarded way round it.

[e301988325i]

Murran the ABS relay is cica £50, it is possible to repair them if they blow but not always. Just at the moment in time, keeping the ABS working seems like a good idea. Disconnecting the relay, which is hidden above the glovebox is much harder work than the three secods it takes to turn everything electrical on.

[Brianmoooore]

i'l almost immediatly compensates for the load your putting on the battery

"almost" is the key word here! Almost, on an oscilloscope, looks exactly like a voltage spike, which can, and often does, trip the zener protection diode in the ABS relay.

[murran]

then pull it out, better that than possibly knackering up a even a slightly weak battery your jumping off.

ive done it and got the t-shirt!

ive jump started lambo guiarrdo's, lotus elise's, audi a8's, bentley coupe's, lincon navigators ffs (yes i work on all sorts of piles of sh1t)...... never any problems...... who's more qualified?

anyway i very much doubt you can blow up relays and fuses unless your a dumb ass connecting the jump leads the wrong way round!
have you guys actually had this happen or are you just reading stories on threads?

[Brianmoooore]

have you guys actually had this happen or are you just reading stories on threads?

Two in the last week, IIRC!

[murran]

it would be a first for me damaging anything from jumping a car. must be just the abs relay your on about on e30's. as i said ive jump allsorts of cars, no probs.

id still jump a car with the jumper car running everytime, no matter what it is.

[clipper]

Well I never though that this would be such a long thread !

I'll fire it up tomorrow off the E39, and as I said before I can guarantee that I won't damage my ABS relay, no matter what I do.

I will however be following some of the advice given.

Thanks to all contributors.