Cummins ISL400 runs and quits... questions

[MarcW]

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

[zmotorsports]

I had an issue with my 03 Dynasty right after getting it in 2007. Very similar situation with the exception that we were driving it and it shut down. Restarted and shut down again almost instantly.

After going through the wiring schematic I noticed that it was tripping a circuit breaker in the front run panel. I unhooked the three (or four, can't remember exactly) wires from the circuit breaker and ohmed each one out. Found one directly shorted to ground. Traced it and found it was connected to the front television lockout feature. The previous owner had at one time messed with the front television and apparently pinched a wire. I don't know how long it had been pinched but it decided to wear through and short to ground after we took ownership.

I left the wire disconnected because at the time I was diagnosing this on the side of the road. Once I got home I removed the television and found the problem and repaired it.

On a side note, the lift pump should not run as long as the Cummins tech told you. If you are priming the system such as after a fuel filter change and turn the key on it will run for a couple of minutes. I generally cycle this a couple of times to ensure the system is primed. Once fully primed and prior to starting it will only run about 30 seconds or so. I ended up changing my lift pump in 2007 due to leaking from the ULSD diesel but it was still working fine. PITA to change due to its location nestled right up next to the frame on the side of the engine.

On another note, DO NOT let them tow the coach with a front end or wheel lift style tow truck. Only let them tow it on a low boy trailer. The reasoning is that with a tag axle coach when the front end is raised it exerts a lot of leverage and pressure which ends up being transferred to the tag axle mounting locations at the frame. They will break away from the frame if not towed properly and by properly I mean on a lowboy trailer.

In 2009 (I think that is the year) Monaco added some gussetting to the vertical supports for the tag axle where they meet the frame but they still recommend not lifting the front end to tow. I borrowed a coach from my local dealer and made copies of the gussets and added them to my 2003 as a little extra ensurance but please insist on a lowboy trailer if you need to be towed.

Mike.

[JetAonly]

As it is an '06 for emissions it may have lift pump seals not designed for ULSD. If you can see it it may leak fuel, mine did. Your symptoms are similar to when mine quit. If it is the old style lift pump you can tighten the top bolts, that got me home ~1500 miles. If it is leaking out the electrical connection you will probably have to have it repaired. Bad fuel is always a possibility, too.

[spritz_55423]

We had a hiccup last season up Northern Minnesota, Sunday night around 9:30 10:00 PM two lane hwy and when I stopped the rig I was still a little on the Hwy. I mean its the darkest I have ever seen (scarey too) cars, MHs 5th wheelers flying by. I quickly got out my reflector triangles and went to go out the door and there was like a 3 foot drop after the last step I didn't see it coming. Picked myself up and set them out.I think if I would have gone a inch over more I would have flipped the rig I swear. We called our Insurance company because I have towing on the coverage. They said that they will find a tow company, remember its a Sunday night, but the gal called back within 5 minutes with the tow company on the line and he was 100 miles away but he said he will be there in 2 hours and he was. He hooked up the 30 Foot Pace Arrow, my partner went with him (get this he towed another car to the location with his wife to drive me and our other dog.) Long story short the Pace Arrow went faster than I drive her and we got to the MH dealer and went to bed. Got up the next morning and the service tec came out and looked and listened to me explain what happened and climbed under the rig and changed both fuel filters. That was the problem, fuel filters. He towed us almost 75 miles. Every thing was covered by our insurance Company. We got a call a few weeks later asking us if we were happy with the service we received. I still can't believe the service we had that night. 100% Happy Camper. I will refer that towing company any time.

[MarcW]

djedgar wrote:
Marc
Have you checked to see if they put your fuel filters on correctly? When we had the Ventana serviced they reversed them. After about 450 miles, it started running poorly and the engine died a few times. Turns out, the lift pump was stressed by having to pull fuel through the filter instead of just pushing it to the next one and it was operating only intermittently.

We changed the fuel filters twice in the interim of trying to figure out the problem. With the new lift pump she is running like a champ again.

Thanks Joyce, Although I have a lot of confidence in the people who service the coach I will certainly make sure that when she is getting checked that that is looked at.
I just had another long talk with the service tech at SW Cummins and he is thinking that it is probably electric now but will be bringing the lift pump anyway.
One thing that I failed to mention (too much to think about) is when the engine stops it displays a check engine light and the needles swing back and forth and don't stop until I turn it off. The light resets and does not come back on until I repeat the restart/stop.
I hate this kind of guess what's wrong kind of thing. I would rather just have something break.

[MarcW]

Mr.Mark wrote:
MarcW, how many miles do you have on your '07 Dynasty?

MM.

Just turned 49k

[djedgar]

Marc
Have you checked to see if they put your fuel filters on correctly? When we had the Ventana serviced they reversed them. After about 450 miles, it started running poorly and the engine died a few times. Turns out, the lift pump was stressed by having to pull fuel through the filter instead of just pushing it to the next one and it was operating only intermittently.

We changed the fuel filters twice in the interim of trying to figure out the problem. With the new lift pump she is running like a champ again.

[Mr_Mark1]

MarcW, how many miles do you have on your '07 Dynasty?

MM.

[The_Texan]

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]

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]

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]

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]

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]

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:)

[traveylin]

might consider changing the fuel filter