| 5500 Onan won't run [message #198514] |
Thu, 14 February 2013 20:58  |
John Sharpe
Messages: 489
Registered: February 2006
Location: Texas
Karma: 1
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The genset is a model BGM. I don't have any model specific maintenance manual info on this genset. The problem is the genset starts and dies. It's like the controls don't switch over to run. The starter seems to drop out as soon as the engine starts even if the start switch is held down. Onan manuals for several models seem to address the low oil pressure switch and the presents of 12V current produced by the generator. I took the wire off the oil pressure switch and still had the same problem. Since the starter drops out when the engine starts, I assume current is being generated as that is the only way the board would know that the engine had started. A previous owner ran independent lead to the fuel pump and did not use the board to operate the fuel pump. It seems that both of these malfunctions point to a bad board. Is there a guru out there that can shed some light? This is a link to pinout of the control board:
John Sharpe
Humble,TX
'78 Eleganza TBI
'89 Spectrum 2000 MPI V-10
'40 Ford Panel Delivery TPI
johnasharpe@gmail.com
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| Re: 5500 Onan won't run [message #198533 is a reply to message #198514] |
Fri, 15 February 2013 08:48  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Is the switch normally open and closes with pressure? In that case you would need to ground the switch lead as a test. You can see if switch is N/O with lead off and engine off it would be infinite Ohms sensor to grd.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: 5500 Onan won't run [message #198576 is a reply to message #198533] |
Sat, 16 February 2013 07:39 |
John Sharpe
Messages: 489
Registered: February 2006
Location: Texas
Karma: 1
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Senior Member |
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| Quote: |
....Is the switch normally open and closes with pressure?....
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Don't think so. Onan is all concerned that the wire is not shorted to the engine (ie ground). Good point though to check the switch with a ohm meter after removing the wire from the terminal. Reading from terminal to base should read infinite.
John Sharpe
Humble,TX
'78 Eleganza TBI
'89 Spectrum 2000 MPI V-10
'40 Ford Panel Delivery TPI
johnasharpe@gmail.com
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| Re: 5500 Onan won't run [message #198587 is a reply to message #198514] |
Sat, 16 February 2013 08:59 |
An87ttype
Messages: 157
Registered: September 2012
Karma: 0
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Senior Member |
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I clipped this out of the troubleshooting guide i have. It sounds like you might of seen this but here it is for anybody else that's interested.
ENGINE RUNS 3 OR 4 SECONDS -THEN STOPS*
1C. Checkoillevel.RefilltoFULLmarkondipstick.Doesenginenowcontinue to run?
2C. Check voltage from terminal 11 to 12.Is it 12 volts with engine stopped and does voltage drop to zero when engine runs?
3C. Check oil pressure sensor wire for shorts to ground by visually tracing wire from S2 low oil pressure switch to control.Is wire grounded?
4C. Replace or repair wire making sure it isn't rubbing against anything that may again cause a grounding problem.
5C. Replace low oil pressure switch S2 . NOTE:Remote control leads may be shorted or grounded.
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1975 Eleganza II
Hudson Valley NY
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