Suspected Chassis Electrical Issues

[Aviator]

Hi All

We're talking about a MCI 102 C3 with a Cumins L10-30

I started it up about a week ago (during a cold snap) to move it inside to work on interior projects.

Block Heater plugged in overnight, Started Fine  Good oil pressure, but the air dryer was frozen.  No problem there, I have a heat gun on a stick for this problem, turned on the fast idle, and went inside to take care of other things, and wait for the thaw

Came back out in about 30 minutes and the bus was no longer running. Tail lights were still on indicating the master was still on.

Inside the low air light was out, about 125PSI on the gage, and the master was confirmed on.  Tried to crank it and It started then died out, and did it again shorter on the second crank.

Great  I assume I have a fuel gelling problem and have a fuel line block and have now lost my prime.  Waited until today to further trouble shoot the issue since it 54 here in Northwest Indiana today.

Pulled the fuel filter and found it full of fuel, seemed odd but put it back on and tried to crank it.  No Luck and no hint it would start.

I earlier had suspected an electrical or ground problem because occasionally the engine would stop for no reason but simply turning off the master and waiting a minute or two and it would fire right back up.  I'm not really driving it anywhere, just in and out of the shop to work on it so I figgured I'd tackle this problem later. Oddly during these episodes the engine would run on Fast Idle but die if i turned off fast idle or did anything else that would drop the Fast Idle

So Suspecting electrical gremlins I verified the master relay was closing and that I had power to the Rear Electrical Bus. All good.   

Then I discovered the maintenance manual I have doesn't match up with my chassis ( I have the book for a 102A from 85 and my bus is a 102C from 92)

Standing at the back looking at the Rear Electrical box I see the symptom but don't know where to go from here.

When the master is turned on I can see the relay marked FUEL SOLENOID close for a couple of seconds and then open under load ( i can see it arc) and at the same time, I hear a circuit breaker go ping.  if I wait with the master off, the CB will cool I can hear it reset itself and if I turn on the master again, the same thing happens.

So Its obvious to me that something past the FUEL SOLENOID relay is shorted but I'm not sure where to look, and without a wiring diagram I'm flappin in the wind.

So, does any one have the engine control schematic page from a 102 C3 manual that can give it a look (or make it a pdf and PM it to me) and let me know what the wires are on that relay so I trouble shoot further?

Also Does anyone have a source for a Cummins L10-30 engine service and maintenance manual?  I probably should add that to my library as well

Thanks Guys

Larry

[luvrbus]

Turn the fuel solenoid on manually with the thumb screw on the shut down solenoid if it keeps running the fuel solenoid has a short   

[Aviator]

Turn the fuel solenoid on manually with the thumb screw on the shut down solenoid if it keeps running the fuel solenoid has a short   

Thanks Luvrbus  I'll give that a shot the next time I'm at the bus

Larry

[niles500]

And that is why they call him Bus Yoda, happy new year Clifford

[B_K]

And that is why they call him Bus Yoda, happy new year Clifford

Yup and Happy New Year to Clifford and you too Niles! (are you in FL?)
   BK