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MarcW's avatar
MarcW
Explorer
May 20, 2013

Cummins ISL400 runs and quits... questions

I'm currently stuck in a RV campground with a engine that won't run.
I called and talked with the nearest Cummins service center and the tech on the phone says he thinks it's the lift pump.

The problem goes like this... After getting parked after a normal 250 mile day driving, I started the engine again later and it ran for about a minute and then quit. That was a first. I started it again and did the same thing. I got a "engine comm error" on the dash.

It repeated the same thing several times so I took a break to go on line to search the engine comm error thing to see what I could find out.

One person said that they had a similar event that was caused by a "WIF sensor", another said to disconnect the chassis batts and reset.

That was easy so I did it and the engine started and ran. I let it run long enough to come up to temp and it ran perfectly but I had to shut it down because it was getting late and I didn't want to make everybody mad.
The next morning I restarted and once again it quit, so what exactly caused it to run normally on the previous start and now go back to the problem again is unknown.

When I turn it on the lift pump runs for 30 seconds. Same amount of time every time I do it. The tech said it should run for a couple minutes.

At this point we're waiting on the lift pump and then they will make the 45 mile drive out to diagnose and hopefully fix the problem.

Anyone have any thoughts on what else might be going on? It acts like it is simply running out of fuel after it starts but the "engine communications error" sounds electrical to me.

The coach is a '07 Monaco Dynasty.

Thanks in advance for any insight you might be able to give me..... Marc
Class A
  • The_Texan's avatar
    The_Texan
    Explorer
    May 20, 2013
    If you got a bad load of fuel, it makes no difference if you just changed the filters. The price of a lift pump and the price of a Cummins service call, would lead me to change them again, just for peace of mind. I would take them out and pour the fuel into a clear glass container, so I could see what is in there. Also, my pump only runs 30 seconds or so, so that makes me suspicious of the tech from the get go. My next move would be to chase the ground wire to the Cummins ECM and make sure it is clean, with a Comm error......Sorry, but unless I had an extreme deadline to meet, Cummins would be my last resort.
  • Ivylog's avatar
    Ivylog
    Explorer III
    May 20, 2013
    Guess I have a dumb speedo. While Monaco Support deals with the house... not so much the chassis I would still call them at 800-634-0855. I agree it's more an electrical problem and doubt that changing the lift pump will solve your problem. Does it still shut off in a minute if you keep the revs above 1200+ ?
  • MarcW's avatar
    MarcW
    Explorer
    May 20, 2013
    Ivylog wrote:
    My lift pump only runs for 30 seconds before it shuts off. How did you come up with "engine comm error"? Do you have a code reader? Before I'd let it be towed, I'd be unhooking the batteries every 5 miles if necessary to get to Cummins.


    Thanks Ivylog... The repeated 30 sec shutoff on the pump seemed normal to me too and why I'm questioning the lift pump being the problem.
    I get the engine comm error readout on the LCD screen in the speedo where it normaly says "engine not running" when the key is turned on before you start.
    I don't have a code reader and wouldn't start to know how to use one if I did. The tech on the phone said they would be bringing that equipment when the come out.
    Also... it's a '07 with a '06 ISL 400 and that "reset" only worked once. Haven't been able to do it again.
  • MarcW's avatar
    MarcW
    Explorer
    May 20, 2013
    traveylin wrote:
    might consider changing the fuel filter


    Yes, I'm sure that is always a possibility but, the filters were changes 700 miles ago (along with the oil) just before I took off on this trip and there has only been one half tank fill-up since then at a Loves TS about 200 miles ago.
    The engine ran normally as far as temps and oil pressure at all times during the trip and also while it was running the one time that it did during this ordeal.
    I will be having all the filters checked or replaced before any hard parts on the engine would be replaced. I'm assuming that the Cummins service tech will do things in the right order.
    What I'm really hoping to do here is have any and all possibilities covered so they can be looked at here rather need to have it towed back to their facility.
    Also, just to be clear... when it quits, it's not like it is starving for fuel and then quitting. It just stops like you turned the key off.

    The thought of towing a 43' coach is frightening.
  • Ivylog's avatar
    Ivylog
    Explorer III
    May 20, 2013
    My lift pump only runs for 30 seconds before it shuts off. How did you come up with "engine comm error" as that is not an option on my dash. I did a google search and did not find anything on this code/error. Before I'd let it be towed, I'd be unhooking the batteries every 5 miles if necessary to get to Cummins.
    Even though you posted ISL 400, do you have a 425 ISL? Sounds like something to do with the regeneration cycle.
    *WaterInFuel sensor so drain your primary fuel filter and see if you have any water. Mine is near the mud flap on passenger side. If no water, unhook it.
  • PapPappy's avatar
    PapPappy
    Explorer
    May 20, 2013
    You sound as if you're doing all the right things.
    Your comment about how it acts like it's running out of fuel, could also indicate a bad fuel filter. And don't think just because you may have changed them recently, that it couldn't be that....(unless you JUST changed it).

    I've had problems with fuel, that had me changing out the fuel filters daily! I had to flush the tank, to get it back to the normal 300 hours on the filters.

    Also, as soon as I's shut down the engine, the fuel gauge would go back to normal, and the engine would start right up again, but within minutes, the fuel gauge would start showing a vacuum, and the engine would start being fuel starved and cut off.

    We had growth in the fuel. Be used an algae eliminator (forget the name though), which helped, but as I said, I ended up flushing the tank.

    I would think that the lift pump would run, until it reached pressure, and if it did that in 30 seconds, so be it...but I may be wrong there! I've had similar problems with the fuel pump on our Onan Genset, and it would cut out after a few minutes (overheat, I guess, so tripped, and I could restart it a few minutes later). Replacing it made the difference.

    Hopefully, you will have the same results....though it's strange that it seemed to be fine, after you "rebooted" with the disconnect of the battery?????

    Good Luck:)

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