imobiliser + bump starts - james
I got accosted by a Greek man with a Rover 400 with a flat battery last night. He asked me for Jump leads which I didn't have but I tried giving him a tow. Car turned over OK but wouldn't start. We decided it was the immobilser that was preventing it starting. Is it possible to bump start a car with an immobiliser, if so how?
Re: imobiliser + bump starts - Mike H
Can't see it being a problem if the key is in & the ignition on. Unlocking the car & turning the ignition on should deactivate the immobiliser. Unless it's the yellow clamped-round-the-wheel type immobiliser :-)......now that would make it difficult to bump start....
Re: imobiliser + bump starts - markymarkn
Unless the battery was totally flat I would think there would be enough juice to turn the immobiliser off.

If the battery was completely brown-bread however, could you not tow the car in gear, to turn the engine over so the alternator supplies the electricity to turn the immobiliser off? Turn off said immobiliser and car should start?

I suppose it mainly depends on what kind of immobiliser you have.

Mark.
Re: imobiliser + bump starts - Mark (Brazil)
prob. depends on whether or not the battery is *so* dead that it is soaking all the power up before it gets anywhere near spark plugs or electric bits.

Given that if the battery was dead on a car that had been moving, there's a fair chance that a duff alternator actually caused the battery to die in the first place.
Re: imobiliser + bump starts - Steve G
Depends on how flat the battery is and what type of immobiliser.
Re: imobiliser + bump starts - Flat in Fifth
You can't bump start relying on alternator to produce juice when the battery is dead, bang flat. The magnetism in an alternator is produced by the field coil which requires a battery to produce enough current so that the field coil can produce enough magnetic field which then......

Dynamos are a different thing as the iron magnets still retain enough residual magnetism to produce a bit of power from bang flat.

Of course you could resort to a trick I once did, connected torch batteries to provide enough juice to give the alternator enough to get going, but it was desperation stakes at the time.
Re: imobiliser + bump starts - David W
James,

>I got accosted by a Greek man with a Rover 400 with a flat battery last night...

That is what they all say. I think this is on the wrong thread and "Dave" should be involved somewhere.

;-)

David
Re: imobiliser + bump starts - Cliff Pope
Could it be something in the computer ignition control system?
They always say don't try to bump start a car with an ems because it will upset the system if not activated via the starter motor.
I don't know why not, or if true.