| Author | Message | ||
| jr villanueva (Jrrockstar67)
Registered Member Username: Jrrockstar67 Post Number: 1 Registered: 2-2009 Posted From: 64.234.241.235 Rating: |
MY BUS STARTS AND RUNS FOR ABOUT 35-45 SECONDS THEN SHUTS OFF LIKE IF I HAD SHUT DOWN THE MASTER SWITCH,ALL POWER TO THE DASH SHUTS OFF,THEN AFTER A FEW SECONDS COMES BACK ON,A MECHANIC CAME DOWN AND SAID THE #3 CIRCUIT WAS GETTING VERY HOT,DONT HAVE ANY WIRING SCHEMATICS,CAN ANYONE HELP ME?THANKS... (Message edited by jrrockstar67 on February 17, 2009) | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 731 Registered: 8-2006 Posted From: 64.55.111.6 Rating: |
JR, These buses are equipped with automatic resetting circuit breakers, so when they trip, after several seconds they will reset. This explains the shutdown, and the recovery. These buses are shutdown by air pressure, so if this happens after starting with no air pressure, the engine will not stop until air pressure builds up to about 80 psi, and the protection valve opens and charges the auxiliary reservoir. Your problem is either a bare spot in a wire touching ground in that circuit, two wires with bare spots touching each other somewhere, the voltage regulator could be shorted, a ground in the field circuit of the alternator, or a shorted coil in the Skinner valve. This is the valve that controls air pressure to the shutdown cylinder on the engine. Someone here is offering maintenance manuals for sale, look way down the postings, as it has been a couple of months, or look in the archives. MCI will have a manual, and you need one to fix this problem, and for future. A suggestion is to find the circuit breaker that is tripping, (you can hear it click on and off) and read the number attached to the wire on a metal tag. I realize you have said #3. Look in the front junction box for that circuit number, and disconnect one wire at a time from the stud in the box. With the offending wire removed, not the wire feeding the stud from the breaker, the breaker will stay on. Now all you have to do is figure out what that wire feeds! It will also go to the central junction box in the bays, and to the rear junction box, then to the Skinner valve. With a schematic diagram and an ohmmeter, its easy, really tough without. Good luck, George | ||
| jr villanueva (Jrrockstar67)
Registered Member Username: Jrrockstar67 Post Number: 2 Registered: 2-2009 Posted From: 64.234.241.235 Rating: N/A |
THANKS FOR YOUR HELP,ORDERED MANUEL,COMMING SOON,MEANWHILE DID WHAT YOU SAID DISCONNECTED ONE WIRE AT TIME FOUND #70 WIRE IN THE REAR JUNCTION BOX DRAWING 60+AMPS,DISCONNECTED WIRE,BUS NOW STAYS RUNNING BUT NOW THE NOT GEN LIGHT IS ON,REINSTALLED #70 AMP WIRE,BUS IS STAYING ON STILL BUT THE NOT GEN LIGHT IS STILL ON | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 733 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
JR, Very good! The voltage regulator requires power from the master switch to field the alternator and determine what the actual battery voltage is. In mine, the reg is in the central box, and the field wire runs from the reg to the alt thru the rear box. Can you see which conduit the #70 wire goes into, and then follow it? G | ||
| jr villanueva (Jrrockstar67)
Registered Member Username: Jrrockstar67 Post Number: 3 Registered: 2-2009 Posted From: 69.15.129.205  Rating: |
TRACED PROBLEM TO REMOTE START FROM REAR,DISCONNEDTED IT,ALSO FOUND RUSTED WIRE END AT THE REGULATOR,CUT AND CHANGED WIRE END TERMINAL AND LEFT THE REAR REMOTE START DISCONNECTED,BUS IS RUNNING GOOD NOW,THANK YOU ALL FOR ALL THE GOOD ADVISE YOU ALL ROCK!!!!THANKS AGAIN..... | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 743 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
JR, Thanks for the thanks, we really appreciate hearing back when something works! Regards, George |
