this last weekend i jump started one of my friends mustangs(needs a new starter to high of compression) anyway i didnt turn my car off just hooked my live car to his dead car well the next day a friend who was there told me that that can set your cars computer all mested up. if you dont turn off your car does it mess up the computer. if it does what should i do

 

hasnt ever messed mine up, but i dont know for sure

 

your supposed to leave your car on. As long as you do it in the proper manner i can't imagine anything would go wrong. Remember, its not negative to negative, its negative to ground.

 

remember to ground to the block on your car

 

Yup, you can really do some damage by helping somebody else out. I don't even carry jumper cables anymore for that reason. In fact, the Security force at the place I work won't even jump anybody anymore for that same reason. Hooking the cables up incorrectly can really fry the ECM. A fried electrical system in the dead car (which probably caused it to die in the first place) can also fry your system. Moral: No good deed goes unpunished.

 

Dead battery positive to Good battery positive. Then good batt negative to dead vehicle ground, use engine block. That way if there is a spark it will happen away from the battery and limit the possibility of a spark caused battery explosion. It will also limit any voltage spikes that damage electronic component. I always turn my truck off before connecting. If the vehicle will not start I then start mine and let it run a minute or so to recharge the dead batt. Then I try to start the dead vehicle. If it still will not start I disconnect and get a battery charger. When you disconnect remove in reverse order. Make sure the dead vehicle battery connections are clean. Clean them if they are not. Do not let the vehicles touch. If they are touching they may be already grounded and when you make the last positive connection it will spark and this could result in an explosion. I carry booster cables in my vehicle at all times. I don’t make it a habit to boost all the time but I won’t leave anybody stranded if I can help. Check your owners manual under roadside emergencies.

Regards

Jean Marc Chartier