Bus wont start

[buswarrior]

Only if the DDEC is wired thru the battery switch...

Not a reliable procedure for a newbie that just discovered he actually has a DDEC, and can't get it to start by himself.

There is much danger to hurt oneself, when you don't know about buses and their variables.

Joe, get some experienced help onsite, the advice on these boards has always assumed a certain base knowledge, and miss oh so many basic safety steps and required checks and knowledge about the particular coach and it's unique workings.

Previous owners change things, bypass things, render protections useless, the current mechanical condition... the coach starts, won't shut off, brakes won't hold it, it's in gear, it's in neutral and it still moves, even down to where you stick your fingers and arms without knowing...

Please be careful, there is a lot to know that isn't typed on the internet.

Happy coaching!
Buswarrior

DDEC II will shut down if you cut electrical power to it.   Just turn the start batteries off, and the engine will stop because there's no power for the injectors.   Simple!

John

[luvrbus]

This post is indeed interesting to say the least ,it would not surprise me if he has a Allison 741 with a shift tower instead of the pad 

[bevans6]

Very late to this thread, but popped in and saw the advice to open the master battery cut-off switch on a running engine.  If you open the battery cut-off switch when the alternator is producing power, the voltage regulator loses it's reference voltage and can/will tell the alternator to produce full power by applying full voltage to the field coil.  Depending on the alternator, full output could be 30 - 120 volts, which could obviously do harm to anything connected to the electrical system of the bus.  This was a big issue when we were racing - we gradually switched from cars with a full loss electrical system, just a battery, where the need was for a simply battery disconnect switch, to cars that had alternators to run high current ignition systems and computers.  We went to a battery disconnect with a resistor to drag down the field voltage and stall the alternator so it couldn't continue to produce voltage.

[luvrbus]

Very late to this thread, but popped in and saw the advice to open the master battery cut-off switch on a running engine.  If you open the battery cut-off switch when the alternator is producing power, the voltage regulator loses it's reference voltage and can/will tell the alternator to produce full power by applying full voltage to the field coil.  Depending on the alternator, full output could be 30 - 120 volts, which could obviously do harm to anything connected to the electrical system of the bus.  This was a big issue when we were racing - we gradually switched from cars with a full loss electrical system, just a battery, where the need was for a simply battery disconnect switch, to cars that had alternators to run high current ignition systems and computers.  We went to a battery disconnect with a resistor to drag down the field voltage and stall the alternator so it couldn't continue to produce voltage.

He does not want to be jacking around turning a master switch off and on on a DDEC engine especially on a DDEC ll that is 12v only on a 24v system with a center tap for the 12v supply to the ECM