Flat Battery-Safely jumpstart your Euro

[Tobster]

I recently roll started my car after i left the keys in the ignition with the accessories running for too long.

Maybe I'm just confused but I'd always been led to believe that you couldn't (or maybe it was shouldn't) roll start a fuel injected car? Unless it depends on how flat the battery is: what's going to power the engine management and injectors?

Something about stuffing injectors?

Anybody?

[Chris_F]

well the battery still ahd enough charge to roll down the windows and unluck the car it just didnt have enough charge to display the dash properly (flickering as the OP said)... it started up ok and ran perfectly fine after being roll started (in reverse i might ad lol)

[aday]

Maybe I'm just confused but I'd always been led to believe that you couldn't (or maybe it was shouldn't) roll start a fuel injected car? Unless it depends on how flat the battery is: what's going to power the engine management and injectors?...

I believe the problem lies with push-starting cars with catalytic converters.

From http://www.tribuneindia.com/2005/200...y/motoring.htm:

"If you bump-start or push-start a car, the fuel pump will be activated before any of the systems begin to function. If the fuel pump is working, fuel which has not been fired up will flow into the exhaust system and into the catalytic converter. When the engine fires up, the excess fuel will catch fire and cause extensive damage to the catalytic converter."

[aaronng]

I believe the problem lies with push-starting cars with catalytic converters.

From http://www.tribuneindia.com/2005/200...y/motoring.htm:

"If you bump-start or push-start a car, the fuel pump will be activated before any of the systems begin to function. If the fuel pump is working, fuel which has not been fired up will flow into the exhaust system and into the catalytic converter. When the engine fires up, the excess fuel will catch fire and cause extensive damage to the catalytic converter."

In your car with a fully charged battery, when you turn your key to "ON", the fuel pump runs, but you don't get a bang in the cat. Why? Fuel injectors require electricity to spray and if you don't have power to your injectors, you don't get fuel in the cylinders.

Anyway, when your car is in gear and rolling, the engine will be turning and the alternator will be providing enough juice to run your car even with a flat battery.

[aaronng]

Maybe I'm just confused but I'd always been led to believe that you couldn't (or maybe it was shouldn't) roll start a fuel injected car? Unless it depends on how flat the battery is: what's going to power the engine management and injectors?

Something about stuffing injectors?

Anybody?

When in gear and rolling, your alternator provides the power to run everything. How do you think that your car is able to idle as well as charge the battery at the same time? The alternator provides for everything. Just make sure you turn off your A/C when push starting. If the compressor kicks in, the spike in the current draw can wear out your alternator.