Why wouldn't my Jetta TDI jump start off another car?

[Howie]

The Jetta will never know the difference between  a battery or a starter unit (which, if portable, contain batteries).  Cory's statement that it takes more amps to start a diesel is correct.  Anyone remember the Oldsmobile/Cadillac diesels that had two batteries and still did not want to crank well in the cold?

[Bun-bun]

The Jetta will never know the difference between  a battery or a starter unit (which, if portable, contain batteries).  Cory's statement that it takes more amps to start a diesel is correct.  Anyone remember the Oldsmobile/Cadillac diesels that had two batteries and still did not want to crank well in the cold?

Dodge's diesel trucks have all had a dual battery setup. Such fun putting out for two 850CCA batteries every 4-5 years.

[cyrus buelton]

The Jetta will never know the difference between  a battery or a starter unit (which, if portable, contain batteries).  Cory's statement that it takes more amps to start a diesel is correct.  Anyone remember the Oldsmobile/Cadillac diesels that had two batteries and still did not want to crank well in the cold?

So is there anyway I can jump it with a car?

having a vehicle that can't be readily jumped by my other blows.

[redxblack]

That's why we sold our Jetta.

[Rev. Millertime]

So does BMW put the battery in the trunk straight out of the factory or whas this a spare power source for a sound system? 

Battery is installed in the trunk for weight distribution.  If i remember correctly, the M3 has a 51/49 weight distribution front to rear.

[cyrus buelton]

That's why we sold our Jetta.

Yeah, but you a bit different situation with the computer getting fried.

Just curious...


how did you have the batteries connected during the jump?

I've always done 2 on the good, pos on the bad and the other grounded to the frame

[ryandalling]

Grounding to the frame helps you from frying the electrical, but doesn't give you as good of a jump. (From what I have been told.)

[Howie]

I jumped my wife's jetta and it cooked the computer onboard. My mechanic told me that the VWs need a full charge to kick over, which is why charger boxes work but cables don't. He said that IF I were to jump a jetta, I should leave the cables on for 45 minutes.

We fixed and then sold the Jetta for a toyota.

What usually fries an electronic component in a car (any car, including a Toyota) when jump starting is a voltage spike from connecting or disconnecting with the key and component on or the vehicle running.

[Howie]

So is there anyway I can jump it with a car?

having a vehicle that can't be readily jumped by my other blows.

Most of the time your Jetta will start fine with a boost from a car.  The combination of a stone dead battery and other factors was probably just a little too wrong.  Chances are, if you let the other car run for a while it would have started.  Like Mr. Incredible said, in his case, his little Ducati battery started a TDI.

Grounding to the frame helps you from frying the electrical, but doesn't give you as good of a jump. (From what I have been told.)

You want to hook up and disconnect the ground on the dead car last away from the battery to avoid sparks and the possible battery explosion.  Hydrogen and sparks make boom!  A good ground is a good ground.

[rgramjet]

Do yourself a favor.  Invest $80 in a starter pack, compressor emergency light.  Cant tell you how handy it is to have around.  It will recharge off a cigarette lighter plug or household.

[redxblack]

We had it grounded but the jump didn't work. We never got the car started, so I don't think it was a voltage spike turning it off.

[cyrus buelton]

Most of the time your Jetta will start fine with a boost from a car.  The combination of a stone dead battery and other factors was probably just a little too wrong.  Chances are, if you let the other car run for a while it would have started.  Like Mr. Incredible said, in his case, his little Ducati battery started a TDI.

I let my lexus run for 5 minutes connected to the dead battery.

After the diagnostic, the old battery was only kicking out 300 cold crank amps or whatever that is called. The car requires a minimum of 700 per the battery required. Therefore, sounds like the contributing factors led to it not jumping.

Do yourself a favor.  Invest $80 in a starter pack, compressor emergency light.  Cant tell you how handy it is to have around.  It will recharge off a cigarette lighter plug or household.

That's a good idea.

I'll pick one up this weekend 

[acalles]

I jumped my wife's jetta and it cooked the computer onboard. My mechanic told me that the VWs need a full charge to kick over, which is why charger boxes work but cables don't. He said that IF I were to jump a jetta, I should leave the cables on for 45 minutes.

We fixed and then sold the Jetta for a toyota.

Bull.

I've been working on vw's for 6 years now (actually certified as a VW electrical expert), I've jumped MANY cars, using other cars, jumper boxes, all that.

the ONLY time I've ever seen a ECU fry was due to some moron tow truck guy jumping the car backwards.. you ALWAYS know when this happens because the fuse in the back of the radio pops.

the only other way ECU's fry is on the old digi systems if the ground from the starter is bad it will toast the injector circuit in the ecu and the injectors stay on..

Now, Vehicles with immobilizer are very senstive to voltage lower then 10v. the immobilizer pickup will not work at this low power level, which will keep the vehicle from starting, particularly on a tdi.

Cyrus. your vehicle being a 04 stores the radio code and all radio presets in the instrument cluster's gateway (address 19) in non-volatile memory. you can disconnect all voltage to the radio and when power is restored your radio will say "safe" for about 5 seconds then beep and go right back where you had it.

the only things you'll have to reset are the window auto up and down, and the clock.

based on what I'm reading your vehicle's battery had a dead cell, and was only making ~10.5v, plus it sounds like your jumper cables sucked. Its almost impossible to get good cables any more (unless you get them off a tool truck.)

[cyrus buelton]

based on what I'm reading your vehicle's battery had a dead cell, and was only making ~10.5v, plus it sounds like your jumper cables sucked. Its almost impossible to get good cables any more (unless you get them off a tool truck.)

You are correct, I'd have to go look at the diagnostic, but I believe it was only making 10.5v.


My jumper cables do not suck. They are a quality pair I have had for about 6 years.

[acalles]

You are correct, I'd have to go look at the diagnostic, but I believe it was only making 10.5v.


My jumper cables do not suck. They are a quality pair I have had for about 6 years.

I was just giving you crap about the cables.

in all reality the connection at one of the terminals was probably not that good.

If you have a set of cables and a DVOM, next time you can check a volt drop across the cables to see if they have any resistance.

FWIW, my procedure to jump start a dead car.
*if using an other vehicle, make sure its started, running and all consumers are off (ie head lights, radio, all that stuff)

1 make sure key is Off, and in my pocket (I've had cars decide to lock when I connected power, key locked inside =suckage)

2 connect positive to positive terminal.

3 connect negative to negative terminal. I almost never use any other ground unless I have to (like old audi's and twatregs where the battery is under the seat) I've never quite understood why some people say to ground some where else. if there happens to be a voltage spike (good vehicles alt spikes when it sees increased load) the battery, even when dead acts like a sponge, so it will "soak up" the extra shock.

4 ensure all the consumers are off in the vehicle that needs to be jumped.

go ahead and start it.

Now good cables can go bad. They've got thicker wires in them, which don't like to be bent back and forth too often, can break, and can cause a higher resistance. you can allways check them by placing a load across them and checking the voltage drop..

jump boxes.. be careful which ones you get. the sams club, pep boy specials are trash. the've got lights and compresssors and radios and all kinds of junk on them, they don't seem to last very long. in a year and a half you'll be throwing it out.
buy a good one, http://www.cloreautomotive.com/site_cat.asp?family_pk=11&br_pk=37&category_pk=70

I've got the 660, (1700peak amps) works great. I've had it for probably 5 years now, daily abuse, still works great.