Jump start=instant 7K rev up and crapped pants

WTF, let my battery run down again, this is the second time I jumped the car and the thing went straight to redline, and stayed there, switched it off, fired it back up, all good, except my pants, need new ones now. Anyone ever had this happen? No check engine lights.

 

LL

 

Please no "It depends" jokes :-)

The last thing you want to do is jump start your car. You can do damage to the computer. You are better off charging it or getting a new battery for it then put a battery tender on it.

OR - jump start car with donor car "not running" that way you can't voltage spike dead cars electrical system.

holy crap.

 

Last thing you want to do is lose an ECU and have to replace it.

A couple of things come to mind here.

 

1st, the good.

If you are in a bad situation where you need a jump, Get the jumper cables connected correctly and start the good/donor vehicle. Let it run for 5-10 minutes with the idle around 2,000 rpm. Then DISCONNECT the cables completely before starting the Lambo.

By doing this, you are simply "quick charging" the Lambo's battery, but not using a donor vehicle to start it. It is very unlikely to do any damage to the Lambo this way (unless you do something stupid like not correctly connecting the pos and neg on the cables)

 

2nd, the bad.

Any car that starts and instantly jumps to a high rpm is doing so without oil pressure. It may seem to run fine right now, but you probably knocked off 15k miles worth of life/wear on the piston rings and crank/rod bearings.

NEVER rev the engine until oil pressure is at normal reading in ANY car. Even then, wait until full operating temp for any "aggressive" driving.

I agree I would not jump this type of car. There was one at the dealer recently guy fried his computer .... $$$$$ ouch.

 

 

How would the engine suddenly rev to redline? These aren't drive by wire cars. It couldn't happen unless your foot was planted on the accelerator.

Happened to me...

When my 6.0 was delivered, I turned the key and the revs went straight up. Fortunately, I immediately switched the key off. Restarted and all was good.

I did not jump it, and it never happened again. I can guess that it had something to do with being in a transport trailer for about a week.

 

I have since learned that it's a bad idea to start this car on a low battery, because it will most likely give a CEL.

 

Slow charge, or do like SYNYSTR and 360challenge said.