Diesel fuel in my coach has gone bad. Engine doesn't run. What next?

[Funster101]

Due to unexpected (and tragic) circumstances my Safari Sahara has been parked for about 16 months with a near full fuel tank. I run both engines in the coach once a month. Last Thursday the main engine shut down and will not restart. When cranking, the "low fuel" light on the dash goes on. Fuel gauge reads between 3/4 and half. And the generator would shut down if the fuel level drops below quarter tank. Problem may be the main engine fuel pump, but I suspect the fuel has gone bad and is clogging the fuel path.

Any suggestions on how to go about getting the coach fixed? How could it be towed to a shop if I can't get the air pressure up to release the brakes? Is such a repair something a mobile diesel mechanic could/would take on?

[Phil D]

Fuel should not "go bad" to the point that the engine won't run in sixteen months.  While ULSD isn't what diesel once was, it can cause poor performance over a period of many years of sitting, but not to the point of the engine shutting down, and certainly not in your time frame. 

I'd suspect a mechanical problem rather than a fuel-specific problem.  You can try to hire a mobile mechanic, but even if a trip to the shop "on the hook" is necessary, your brakes can be caged (the springs manually retracted via the caging bolts in the brake cans) to make the trip.

[Randyretired]

Depending on what the problem is I would think a mobile mechanic should be able to fix or determine what is wrong.  A good mechanic can fix a lot of things without requiring it to be towed. My neighbor is a mobile mechanic and he has talked about a number of repairs all "in the field".  He does heavy equipment and trucking that to a shop would be very involved, expensive and a last resort.

Edited December 24, 2023 by Randyretired

[Ray,IN]

  My MH sat for 2 years without being started. When I did start the main engine everything was normal.  I knew  the MH would not be started, so I added a biocide to the tank when topping it off to prevent the growth of algae.

Diesel fuel does not "go bad" per se. Now if biodiesel sits for years it will stratify, the pure diesel will rise to the top of the tank, leaving 100% biodiesel near the bottom.  That is not normally a problem unless you also have water in the tank; that situation allows for this condition:  https://criticalfueltech.com/faq.html

If your tank has sediment and algae in it, the fuel filters most likely are plugged up and must be replaced,thus the no-start condition. If the algae is bad you may have a tough time remedying the problem.

As Randy said, heavy construction equipment is rarely worked on in a garage. Mobile mechanics perform the work at the jobsite unless major engine/transmission work is required.

Time for a story. I once bought a diesel farm tractor that had been parked in a fence-row for so long a 4" diameter tree was growing through the frame. I cut the tree, towed the tractor to the road, loaded it and brought it home.

I then drained the fuel tank, poured the fuel off the top of the water through a strainer.. I replaced both fuel filters and drained the carb. Next day I poured the fuel back into the tank,primed the system the turned the key. The engine started about the 3rd revolution and ran fine the rest of that tank of fuel.

The next year I sold that tractor for a $2,000 profit.

Edited December 24, 2023 by Ray,IN

[WILDEBILL308]

I wonder if the OP  Funster101 got his problem solved.

Wanted to point out that if he needs to air up the system, air bags and breaks there is normaley a air fitting on the front firewall. This is what the tow truck uses to add air to the system. I think his problem is fuel / fuel filter related. I would look at the Diesel Kleen website. This is the only additive recommended by Cummins.

https://powerservice.com/psp_product/diesel-kleen-cetane-boost/

Bill

[Funster101]

Thanks to all who replied.

I had decided to park the problem till after the holidays. Next week I plan to call around to see if I can find a mobile mechanic who'll trek up here from Las Vegas to diagnose & fix the problem. If that doesn't wash, will have to work on getting the rig towed down to the Cummins dealer.

As to airing up, there's a standard male air fitting in the rear of the engine compartment. I've used it for airing up tires and doing a quick air dump. Seems I could connect a hose from my big NAPA compressor and pressurize brakes and suspension. Any problems with doing that?

[Lou Schneider]

18 hours ago, Funster101 said:

As to airing up, there's a standard male air fitting in the rear of the engine compartment. I've used it for airing up tires and doing a quick air dump. Seems I could connect a hose from my big NAPA compressor and pressurize brakes and suspension. Any problems with doing that?

No need, any tow truck large enough to tow the motorhome will have their own air supply.

When I was maintaining large diesel generators at transmitter sites, we'd "polish" the fuel every year or two.  Essentially it's passing the dirty fuel through a series of filters decreasing in size to remove water, sediment and microbial contaminates.  When you're done you have essentially new and fresh diesel.  We used a commercial service for our 5000 gallon storage tank but you can DIY for smaller quantities.  Google "diesel fuel polishing" for several articles and  videos.

[Funster101]

Good news. Had a mobile repair technician come out. He ran diagnostics and found that the engine wasn't starting because the fuel actuator had thrown an error code. The engine firmware will not let the engine start until the code is cleared. After the code was cleared the beast fired right up and ran perfectly at high and normal idle. Technician tells me the standard procedure for codes that occur only once is to ignore. If it does hit again, he'll replace the actuator.

The key here is the technician has all the very expensive diagnostic equipment to interface with the engine electronics to read and reset fault information. Don't see how the problem could have been resolved without the proper equipment.

[Kirk W]

3 hours ago, Funster101 said:

Good news.

Great news! And thanks for coming back to let us know the latest. 

[Ray,IN]

A point of general knowledge; do not start the engine unless you can drive the vehicle for 20 minutes to get everything, including motor oil up to normal operating  temperature. A diesel engine will never reach normal operating temperature at low idle.

source: https://www.cumminsengine.net/is-really-good-that-engine-running-with-low-idle-speed.html

 

Edited February 8 by Ray,IN

[mike5511]

2 hours ago, Ray,IN said:

A point of general knowledge; do not start the engine unless you can drive the vehicle for 20 minutes to get everything, including motor oil up to normal operating  temperature. A diesel engine will never reach normal operating temperature at low idle.

source: https://www.cumminsengine.net/is-really-good-that-engine-running-with-low-idle-speed.html

 

I like to double that time, especially if it is cold outside.

[Kirk W]

11 hours ago, Ray,IN said:

A point of general knowledge; do not start the engine unless you can drive the vehicle for 20 minutes to get everything, including motor oil up to normal operating  temperature.

That is true for any vehicle engine if it has been sitting long enough to be considered to be a dry start, according to the Ford tech support folks. They define a dry start as all oil having drained from the lubrication points and it is typically about 2 weeks. The reason that they gave me for driving was to warm not only the engine but also the transmission enough to evaporate any moisture that may have condensed inside and to fully lubricate all critical points in the entire drive train. 

[sandsys]

When we stayed in one park all summer one year, we took our motorhome out for a half hour drive once a month and used that time to run the generator as well. No sense running the generator while in the park and annoying the neighbors.

Linda Sand

[Ray,IN]

On 2/8/2024 at 9:21 AM, Kirk W said:

That is true for any vehicle engine if it has been sitting long enough to be considered to be a dry start, according to the Ford tech support folks. They define a dry start as all oil having drained from the lubrication points and it is typically about 2 weeks. The reason that they gave me for driving was to warm not only the engine but also the transmission enough to evaporate any moisture that may have condensed inside and to fully lubricate all critical points in the entire drive train. 

Recent/this century, diesel engines/Cummins, have a feature in the ECM to prevent "dry starts". The ECM only allows an engine start after the ECM "sees' oil pressure.

My 1999 ISC used to start immediately when the starter engaged. I had work done on the engine and Cummins had to wipe my ECM clean and install the latest version, just to be able to communicate with it, after that my engine cranks a lot longer before starting. I thought something was wrong, but I was assured the new program was the reason, to allow oil pressure to build.

Edited February 10 by Ray,IN

[Kirk W]

7 hours ago, Ray,IN said:

Recent/this century, diesel engines/Cummins, have a feature in the ECM to prevent "dry starts". The ECM only allows an engine start after the ECM "sees' oil pressure.

While that is a big improvement, the engine that has sat for months will still have no lubrication when it begins turning over. Delaying the start does lessen the amount but only a prelube system completely resolves that and looking at the Cummins website it lists a prelube system as optional on some engines. I suspect that starting any engine is the thing that is most wearing thing we do to it under normal circumstances. 

[Ray,IN]

11 hours ago, Kirk W said:

While that is a big improvement, the engine that has sat for months will still have no lubrication when it begins turning over. Delaying the start does lessen the amount but only a prelube system completely resolves that and looking at the Cummins website it lists a prelube system as optional on some engines. I suspect that starting any engine is the thing that is most wearing thing we do to it under normal circumstances. 

i agree, and statistics have proven your last sentence.

[WILDEBILL308]

On 1/7/2024 at 1:20 PM, WILDEBILL308 said:

I wonder if the OP  Funster101 got his problem solved.

Wanted to point out that if he needs to air up the system, air bags and breaks there is normaley a air fitting on the front firewall. This is what the tow truck uses to add air to the system. I think his problem is fuel / fuel filter related. I would look at the Diesel Kleen website. This is the only additive recommended by Cummins.

https://powerservice.com/psp_product/diesel-kleen-cetane-boost/

Bill

Well I hope the OP read and uses this link. If he is parked for long periods of time he needs a biocide.

Bill