How close was he to frying his ECU?

[Xspook]

I always heard this was a no-no...

FFWD to 9:00

https://youtu.be/lNH_VQ7SNrQ?t=539

[ptscon]

If you do it properly, connect the cables in correct order then I don't see what the issue is. Should be no different than connecting stock battery cables to the battery. I probably wouldn't have the car running, just battery to battery.

[K447]

If you do it properly, connect the cables in correct order then I don't see what the issue is. Should be no different than connecting stock battery cables to the battery.

I probably wouldn't have the car running, just battery to battery.

A bigger no-no is boosting a ski with NO battery installed in the ski.

The PWC battery does not just crank the engine. That battery also acts as a buffer to absorb energy spikes and electrical pulses. The installed battery stabilizes the voltages within the PWC electrical system.

ÔÇÿBoostingÔÇÖ the PWC with another external battery is not ideal, but at least the internal battery is there to absorb energy and buffer the system.

Boosting a PWC without a working battery installed can cause any manner of unexpected voltage variations. Which is one way to ÔÇÿfryÔÇÖ electronics.

[steve45]

In the old days, it was common practice to leave the engine running when jump starting another vehicle. DON'T do it on a late model vehicle! The solid state voltage regulator can be fried by current surges if the dead engine is cranked. Leave the ignition off in the dead vehicle and simply charge the battery with the good vehicle. After charging a few minutes, disconnect the jumper cables and try to crank the dead vehicle.