I have done it several times with no apparent damage but I will defer to the judgement of the service man and leave this little trick up to the judgement of the vehicle owner. Maybe some other forum member can post something on this.

It seems to me, and this is just my opinion, that if you remove the ground cable with the engine running and then turn the engine off before reconnecting it, that this would minimize the danger of damage to the computer but that is just my opinion. Of course if the alternator is bad, the engine is going to die anyway so my idea would be moot.

I have heard that just jumping one car to another can damage the electronics so what are we to believe? I know with a truly dead battery, you have to reset the clock and all the pushbuttons on the radio which is a pain. When I was growing up, cars had generators, not alternators and most were straight shift. If your battery was dead, just get someone to give you a push with the car in low or second gear and then let the clutch out when you got up your speed and the motor would start. Ah for the good old days. I guess pushing would still work with a manual transmission. <img src="/images/graemlins/smirk.gif" alt="" />

While i have done exactly what Joe has done to check an alternator, lifting the battery cable off while the engine is running can cause a spark and the battery can explode. So be careful.

The links provided above give a good explanation of how to jump start a car. But if you are driving a newer car 90's and up, read and follow the instructions in your owners manual. There can be some unusual precautions that need to be followed. I remember reading one that recomended not jump starting the car, the recomended procedure was to remove the battery and charge it. But if jump starting was deemed nessary that the drivers side door should be open for the duration of the jumt starting procedure. The reasoning was that the engine management computer was on the same curcuit as the dome light. Which hopefully would help to dampen any voltage spikes that might fry the computer which cost quite a few$$.

nice tutorial, and nice website too...thanks!

This is the thing I don't understand...in high school, I always chanted the mantra "positive to positive, negative to ground". Maybe that's why I didn't have a lot of friends <img src="/images/graemlins/blush.gif" alt="" /> <img src="/images/graemlins/grin.gif" alt="" />

Anyway, the first time my father in law helped me do a jump start, he INSISTED that the negative terminals were connected to each other too. I felt it was wrong, but he's the type of person that you can't tell anything to. So when he was around, that's the way we did it.

So my wife left her lights on one day and drained the battery. My mother in law came with her car, and I hooked up the cables, using my old mantra. I was reasonably sure the battery was okay, but let it charge for five minutes or so. It was still as dead as dead can be...let it go for another five minutes...still nothing. Then instead of grounding the negative terminal on the dead car, I put the clamp on the negative terminal...a few seconds, and the car started right up.

I don't understand it, does anyone else?

My wife wouldn't even try to jump start it...she'd call AAA <img src="/images/graemlins/grin.gif" alt="" />

But your point is well taken. Suffice it to say that in Wal Mart's effort to keep prices low, it would probably be wise to consider most products not reliable to bet your life on, eh?

Planned obsolescene...making stuff so it only lasts so long, then it becomes unusable, so you have to go buy another one. Happened with a $300 full face mask for my CPAP...didn't even last a year, while the much less expensive nasal masks last me for several years. Then someone at the medical supply shop said, "Yeah, the manufacturer only expects these to last for six months, because most insurance pays for a new one every six months"

Ah...corrupt capitalism!

I have to admit that some of their stuff looks like it would be cool. I even lingered a bit when looking at it. But then that little voice inside of me said, "It's Eddie Bauer for the sake of Pete. It's about the 'bling', not about the 'zing'! "

Although I must admit that we have Eddie Bauer car seats in our van at this moment <img src="/images/graemlins/blush.gif" alt="" />

In my defense though, we did comparative shopping and decided on it for the quality of it, and not the 'bling' <img src="/images/graemlins/wink.gif" alt="" />

Recently had a problem with the battery on my Renault Clio. A cell collasped creating a short in the battery, it died basically. Renault size the smallest battery they can expecting it to die within two years. As this one did. I didn't know this at the time. Also a funny feature of this car is the engine immobilser. When there is no volts from the battery it defaults to off and has to be reset by the garage. So even if I'd repalced the battery myself I would still be stuck as I don't know how the resetting is achieved. (note to self find this out) (second note to self, don't bother the car was stolen last night. <img src="/images/graemlins/mad.gif" alt="" />) I refused the battery offered by the garage and sourced my own, one with a high or higher Amp Hour rating. Capable of supplying the umph when you need it.

The cables I have I got from a Heavy goods vehicle store rated at something like 1200A in rush. The best set I ever had were made for me when I used to be a designer of diesel generator sets. Had to give em back when I left the company.

1- Always follow the procedure written in your vehicles owners manual.
2- Use biggest / shortest cables for max power.
3- Longer cables will offer better chance of connecting in a tough situation (contradicts no 2)
4- Look into getting a power pack, some have compressors (for flat tires) and you'll never need a 2nd vehicle to jump start your own.

".....the car was stolen last night."

Sounds like somebody did you a favor. <img src="/images/graemlins/confused.gif" alt="" /> Seriously though, I could never own a car like that.

Regards, Vince

This works, and most of us have probably done it this way or seen it done this way at some point (I've done it back as a teenager and didn't know better). The sole reason, as far as I am aware, of grounding the last clamp away from the battery instead of on the negative terminal itself is a combination of:

* The last clamp will close the circuit and may produce a spark
* Batteries can generate explosive gasses so you want to keep sparks away from the battery

By clamping +/+ and -/- terminals, you're closing the circuit and it works, but any potential spark occurs right at the battery. Most times you can get away with it, but it's that rare time that you'll regret it.

4- Look into getting a power pack, some have compressors (for flat tires) and you'll never need a 2nd vehicle to jump start your own.
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Frank, let me offer a little tip about these cheap air compressors. On a flat tire, they will inflate it...........eventually, and usually gets red hot in so doing.
To assist this little fella, jack up the car to get the tire free from the pavement. It will inflate much easier and puts much less stress on the compressor by not having to raise the vehicle in the process. However, by their very nature, all air compressors heat up to some degree.

Boone