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Topic: Boost - Aux Start (Read 709 times) previous topic - next topic

Boost - Aux Start

I see, in another thread, conversation abou two solenoids, being called "Boost" and "Aux Start". Sounds like the same thing to this one who knows nothing. Can the difference be explained ?
Dave W. (AKA Toyman )
'03, 270, 36', Build 6095, Pulling whatever I hook it to.

"Don't cry because it's over. Smile because it happened."
Dr Seuss

Re: Boost - Aux Start

Reply #1 –
Boost Solenoid:  Mechanically connects the "House" and "Start" battery banks together.

Aux Start Solenoid:  When you turn the ignition key to "Start" (or activate the Remote Start Switch with the key in "Run" position), power goes through the Neutral Start Switch (relay) to the "Aux Start" solenoid coil.  The solenoid closes, sending power to the "Starter Mounted" solenoid coil, and the engine cranks.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Boost - Aux Start

Reply #2 –
So, in essence the "Aux Start" is a neutral lockout solenoid ? 
Dave W. (AKA Toyman )
'03, 270, 36', Build 6095, Pulling whatever I hook it to.

"Don't cry because it's over. Smile because it happened."
Dr Seuss

Re: Boost - Aux Start

Reply #3 –
Quote from: toyman –
So, in essence the "Aux Start" is a neutral lockout solenoid ? 
I guess you could call it that.

There may be other "tests" that must be met to enable starting, depending on coach year/model.  Barry did an excellent writeup on this subject:
Start failure-no crank-fixed it.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Boost - Aux Start

Reply #4 –
As Chuck noted:

Neutral Safety relay in on front panel (it takes voltage from ignition key & Allison transmission) and sends voltage to Aux Start solenoid).
Aux Start is a simple solenoid (SPST N/O relay) that takes the 'ok to start' electrical signal, sending higher current chassis battery power to starter (through another solenoid mounted on starter)..
If one wanted to crank engine, they could remove the small positive wire on the Aux Start solenoid and put 12-volts on the solenoid's terminal.  This can be helpful if other circuits like ignition solenoid, neutral start, ignition key, etc were malfunctioning.  But to keep engine running after cranking other circuits would have to be powered, too.

Re: Boost - Aux Start

Reply #5 –
I don't know how the aux start relay is wired on an 03, by on  93 the aux start relay also energizes the pull coil on the fuel shutoff solenoid.

Roland
1993 U280 4341
2010 Jeep Liberty
The Pied Pipers

Re: Boost - Aux Start

Reply #6 –
Hi Roland,

Yep, our fuel shutoff is wired the same as yours.  This is where we put in a relay to delay fuel opening during initial cranking to move the oil around before firing the engine.
When Cummins computerized our engine, about 1998, fuel flow was no longer tied to the aux start solenoid.  And M11's and other engines also control fuel from their computer.

Re: Boost - Aux Start

Reply #7 –
Quote from: Barry & Cindy –
Hi Roland,

Yep, our fuel shutoff is wired the same as yours.  This is where we put in a relay to delay fuel opening during initial cranking to move the oil around before firing the engine.
When Cummins computerized our engine, about 1998, fuel flow was no longer tied to the aux start solenoid.  And M11's and other engines also control fuel from their computer.

Does that mean I dd not need to install a relay to delay fuel opening in my M11?

Re: Boost - Aux Start

Reply #8 –
Long storage periods mean the oil will gradually drain off the protected parts like camshaft lobes, etc. Multigrades will do this faster than a single grade oil. Aircraft piston engines recommend a single grade if not started frequently. There are several aftermarket devices you can find with a Google search to pre-lube the critical engine components before starting allowing any type of oil to be used. Here is a typical device to pre-lube your engine before starting. Moroso 23901, Moroso Oil Accumulators & Accessories | Moroso Some allow an electrical activation to be able to lube the engine from the driver's seat before cranking.

I do remember an aircraft engine notice about the rapid drain off of synthetic oils from engine parts with the recommendation not to use them unless the engine was pre-lubed before starting after storage. We use full synthetic oil in our gasoline powered cars but they never see lengthy periods of inactivity.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)
 

Re: Boost - Aux Start

Reply #9 –
Duane,

All computerized engines manage fuel flow at start up.  Some delay fuel until computer sees some oil pressure.  You can tell how things work by turning the ignition to start.  If there is instant start, no fuel delay.  If you hear the engine crank a few times the computer has a delay for the benefit of engine longevity.  After-market pre-lubers are 12-volt motors that take oil pan oil and pump into an oil chamber under pressure, and are activated before cranking.
Not logical to add relay to delay firing to any engine other than the mechanical C8.3.