Motor shuts off while driving

[Fred Cook]

Hello…. It’s me again. TV lift is working fine now, but now I have another problem. We started out this morning on our 80 mile trip back home. Motor started up fine. We left and at about 10 miles down the road the motor shut off completely while we were doing about 60 miles an hour. I immediately turned the key off and turned it back on, and it started up again. Traveled down the road another mile or two and it started sputtering and turned off again. Again, I turned the key off and turned it back on, and it started up and kept going. At one point I thought I was going to have to pull off the side of the road as it shut off and would not start back up but it finally did. This happened at least 10 times going down the road and finally about 30 miles from home it stayed running all the way back to the house. I recently had all filters changed and new oil so that is likely not the problem. It got down to 18° last night, but I had the block heater on all night and also the aqua hot preheat function. So, would anyone know what is going wrong with this thing??

[Frank Bergamo]

Could be a fuel issue. Fuel might be jelling in the cold weather if you don’t have winter blend in your fuel tank. Also, might be an electrical issue. I would check all battery connections to make sure everything is good and tight.

[Fred Cook]

Frank, I noticed when I got home and tried running the bedroom slide out, it would not go all the way out on its own until I pushed on it. I went out and plugged into shore power and brought it back in and out easily. So I attribute that to possibly a low battery issue. Do you think a low battery would cause a motorhome to shut down while driving? I would think the alternator would keep it going.

[David T. Richelderfer]

After reading your original post on this thread, I too suspected a fuel jelling issue.  A block heater and/or a warmed coach interior due to running the AquaHot/furnace doesn't heat the diesel in the fuel tank and fuel lines running between the fuel tank and engine.  Certainly, an 18F overnight temperature is cold enough to initiate fuel jelling, especially if the diesel has a higher than 5% bio rating.  20% bio in diesel can cause jelling up to nearly 40F.  So, my thought is the fuel was jelling before it entered the fuel filters and started to impede flow through the filters.

After reading your second post, I'll ask what is the at-rest voltage in your chassis batteries?  It's possible your alternator and/or voltage regulator may be weak, resulting in low chassis battery voltage.  Had you experienced the slow bedroom slide issue while on the trip, then you could have started the coach's generator or pressed the Battery Boost to perk up the chassis batteries through the BIRD/Big Boy.().

[Fred Cook]

Dave, thanks for your input. Hopefully it’s an easy fix.

[Frank Bergamo]

It’s very possible a low battery would contribute to your symptoms. How old are the batteries? A load test on the batteries will give you an idea of battery condition. As David stated above, is your charging system working properly? Also very possible the cold temps contributed to the shut down issues. Could be two totally different issues going on. If you had summer blend fuel in the fuel tank, then that may have contributed to the problem. All things you need to figure out before next road trip.

[Richard Davis]

Fred
I have also had the same kind of issues when the ignition solenoid in the front run bay was failing.  It was intermittent at first and would act like I had turned off the switch, but would restart.  Eventually it failed completely.  If that is the problem, make sure you get the continuous duty solenoid as a replacement and be sure to install the little diode pointing the right way.
Richard

[Fred Cook]

Thanks Richard, I’ll look at that too.

[Wayne Ogren]

I have been lurking and learning much from this forum for a couple years now.  Thank you for all I have learned.  We experienced this same behavior driving through Montana, motor died, but would restart, then die again at random times.  Turns out it was the in-dash ignition switch, a unit used in 1970's vintage GM pickup trucks.  When continuity is lost, the engine shuts down as it is supposed to do when ignition is off.  Wiggle the key a bit, restart, and runs fine until the next bumpy bridge or whatever.  Replaced the switch with in-stock NAPA unit and has not happened again.  Avoid using a heavy batch of keys in your ignition switch.

[Fred Cook]

I have been lurking and learning much from this forum for a couple years now.  Thank you for all I have learned.  We experienced this same behavior driving through Montana, motor died, but would restart, then die again at random times.  Turns out it was the in-dash ignition switch, a unit used in 1970's vintage GM pickup trucks.  When continuity is lost, the engine shuts down as it is supposed to do when ignition is off.  Wiggle the key a bit, restart, and runs fine until the next bumpy bridge or whatever.  Replaced the switch with in-stock NAPA unit and has not happened again.  Avoid using a heavy batch of keys in your ignition switch.

I thought about the ignition switch too and bought a new one. But before changing it out I started the coach and wiggled the key around several times and it continued to run normally. Wouldn’t wiggling the key around make it lose continuity the same as hitting a bump?

[Carl Boger]

Fred,

I have had a similar issue where the coach power would occasionally disappear.  Play with the key and everything would eventually power back on.  I ended up unplugging the main harness behind the electrical bay and cleaning the pins on both sides with spray electrical  contact cleaner, soft brushes and mig tip cleaning rods. I used dielectric grease to help seal up both both haves and plugged the harness back together.  That has fixed my electrical gremlins for several years now.

I also bought a spare ignition cylinder to carry as a spare.  I have several keys to the old ignition switch so I won't swap it out until it starts failing if it ever does.  The ignitions are known to fail, or be temperamental all the way back to their use in Chevy's. Wiggling them to the exact spot it fails would be hard to do. Changing them out is easy just carry a paperclip.  I also have a spare door entry lock/latch since it is also known to fail.  If I every can't get in I will be grabbing a drill and drilling it out.

Hopefully this will help you some.
 

[Fred Cook]

Fred,

I have had a similar issue where the coach power would occasionally disappear.  Play with the key and everything would eventually power back on.  I ended up unplugging the main harness behind the electrical bay and cleaning the pins on both sides with spray electrical  contact cleaner, soft brushes and mig tip cleaning rods. I used dielectric grease to help seal up both both haves and plugged the harness back together.  That has fixed my electrical gremlins for several years now.

I also bought a spare ignition cylinder to carry as a spare.  I have several keys to the old ignition switch so I won't swap it out until it starts failing if it ever does.  The ignitions are known to fail, or be temperamental all the way back to their use in Chevy's. Wiggling them to the exact spot it fails would be hard to do. Changing them out is easy just carry a paperclip.  I also have a spare door entry lock/latch since it is also known to fail.  If I every can't get in I will be grabbing a drill and drilling it out.

Hopefully this will help you some.
 

Thank you for providing your experience. I switched out the ignition switch this morning and the old one looked pretty much worn out. Won’t know if this is my problem until I get on the road in a couple of weeks to Dallas. I have a few people on other forms telling me they had the same problem with their motor shutting down and it turned out being a fuel pump relay in one case and an ignition relay in another situation. Others suggested tightening battery terminals, and check for loose ground wires. Very difficult to determine what’s going on here. I am trying to cover all bases before going on our trip. Very frustrating.

[Frank Bergamo]

I believe your fuel pump is mechanical. You can cross that one off your list.

[Fred Cook]

I believe your fuel pump is mechanical. You can cross that one off your list.

The 2008 Caterpillar C13 engine does not use a traditional mechanical fuel pump. Instead, it is equipped with an electronic fuel system that utilizes a unit injection system.

[Frank Bergamo]

Here is your fuel pump. https://atldiesel.com/products/3848611-caterpillar-c13-fuel-supply-pump-new?srsltid=AfmBOooa4R0psbYA3IoHRvApOTc_ZiwDow3iTbf99cD-O-NTpT3-gWa3
On my C-15, it is located inside the engine compartment down and to the right on the engine block. Yours should be similar.