Motor shuts off while driving

[Fred Cook]

Well, I guess I stand corrected. But my rear run box has a “Fuel FTR Relay” labeled on one of the circuit boards.

[Frank Bergamo]

Just a guess, but most of Monaco motor homes have a Cummins motor in them. Different fuel delivery system than the Cat motor homes.

[Joel Ashley]

As others have suggested, the dash ignition can go funky, as ours did long ago on our Pace Arrow.  But pointed out here also was the ignition solenoid in the street side forewardmost bay, a quite common failure device.  So be sure to review online its proper operation, then check that it passes clean and full 12v through as designed.  It's not expensive, easily replaced, and many of us carry a spare.

Also from your description and I believe mentioned here, check your alternator output if your chassis batteries aren't fully charged after a short time on the road.  Many owners break a dry camp without using the generator for awhile beforehand, and overwork the alternator to build back the house batteries, a job its not designed to do, and resulting in its being burned up.

Joel

[Steve Huber]

Hi Fred,
A few observations;
If your radio or other entertainment/dash functions stayed on when the engine died, it probably is not the ignition switch.
If the engine starts immediately after shutting down the fuel pump is probably OK.
A faulty relay, bad connection or fuel jelling is probably to blame. Consider replacing the Fuel FTR (Fuel Transfer Relay) relay out of caution.
Before throwing any more parts/$ at it, consider trying it in warmer weather to eliminate fuel jelliing.
Steve

[Rosemary Allen]

Our 2001 Patriot Thunder with a CAT C-12 had this problem a few years back. Engine would occasionally just shut off. Would restart when key turned off and back on until it happened on I5 where we pulled over to the shoulder and before we could turn the key off/on, the engine just restarted. We took the coach to Bakersfield CAT. The engine died in the parking lot and would NOT restart. The CAT crew was very knowledgeable. They isolated the engine from the rest of the coach after checking the batteries. The engine started remotely with no problem so they reversed the isolation of the engine. They did locate the problem in the front wiring compartment with the main solenoid. Since they didn't have the correct part, one of the techs drove to NAPA Auto Parts to get a new solenoid and installed it. We have not had any further problems. We decided that a 21 year old solenoid had probably done its duty.

[Fred Cook]

Our 2001 Patriot Thunder with a CAT C-12 had this problem a few years back. Engine would occasionally just shut off. Would restart when key turned off and back on until it happened on I5 where we pulled over to the shoulder and before we could turn the key off/on, the engine just restarted. We took the coach to Bakersfield CAT. The engine died in the parking lot and would NOT restart. The CAT crew was very knowledgeable. They isolated the engine from the rest of the coach after checking the batteries. The engine started remotely with no problem so they reversed the isolation of the engine. They did locate the problem in the front wiring compartment with the main solenoid. Since they didn't have the correct part, one of the techs drove to NAPA Auto Parts to get a new solenoid and installed it. We have not had any further problems. We decided that a 21 year old solenoid had probably done its duty.

Thanks Rosemary. As it turns out, my problem was the ignition relay switch inside the rear run box. I took the circuit board off and had it refurbished along with a new relay. So far…. all is good.