Intermittent stop lamp, ISC -- HELP!

[marka]

Howdy,

We're in the middle of our first trip with our new-to-us '99 Dutch Star with an ISC Cummins.

Occasionally the stop lamp & warning buzzer will go off when driving. They go off for perhaps a second up to five seconds, then stop. I can't detect any change in how the coach is running/driving... Engine sounds the same, trans doesn't do anything weird, etc. If the light/buzzer weren't going off, I wouldn't know otherwise.

I've checked tranny fluid level, coolant level in the expansion & overflow tanks, oil level, guages all read normally (air pressure over 100psi, engine temp at 180, trans temp at 180-190, voltage above 12v, oil pressure between 40 and 50 psi.

All were fine. The tranny fluid level was at the bottom line for the 'hot' range, so I added a half quart of trans fluid, checked it again in a little while, then added the other half quart. Level is now at the top of the line for the hot range.

Any ideas? I'm out of them. :-/

Is there anyway to find out why the computer is lighting the stop engine lamp, without a diagnostic tool?

Thanks!

Mark

[marka]

Howdy,

More info (trip continues today)...

After startup and running this morning, it went two or more hours before doing it again, then started again. It seems to possibly be related to the motor/everything being warm, plus having load. When it happens, its when going up a hill and on the throttle (not full throttle, just medium throttle). It also seems to stop if I lift off the throttle.

We just pulled over to check everything out again, as the last hill we went up (not a super steep hill, but reasonable & long...) it would do it most any time I was into the throttle much at all.

Appreciate any pointers. I suppose I should call the extended warranty people.

Mark

[Pigman]

I'd call your chassis manufacturer and find out if this sort of malfunction is recorded in an on board computer someplace and if reading it would help.

John

[Gary RVRoamer]

There is no point in calling the extended warranty people until you have something to repair. They will authorize a repair shop to do diagnosis and repair, but they can't tell you what's causing the problem.

I'd first change the fuel filter(s) just to be sure. Lack of adequate fuel flow fuel in a diesel causes all sorts of thing to go subtly (or sometimes not so subtly) wrong.

Next, get to a Cummins shop and see if an error code has been stored. I think there should be one whenever the engine light comes on, even briefly. You can verify this with Cummins Customer Service before you make an appointment, though.

[marka]

Howdy,

Thanks Gary. I'd come to a similar conclusion, and will be putting on new fuel filters either tonight or tomorrow, then taking the RV to the 'local' (50 miles) cummins shop for them to scan it. Hopefully that's all it is, but I guess the codes will tell the tale.

In case this helps anyone else... I talked to a Cummins customer help line guy and he said I should be able to dump any active codes (i.e. the stop lamp is on when the engine gets shut off) by turning on the ignition (but not starting th engine) and then going full throttle with the accelerator pedal three times. I haven't verified that works, however.

Mark

[marka]

Howdy,

Welp, I don't know if that was the problem, but the chassis rail fuel filter was about the most disgusting thing I've seen in a while... Sludgy, nasty, horrible. The motor side filter didn't look too bad.

I'm wondering now how long that thing was sitting and if there's a ton more crud in the tank waiting to come out and give me another project. :-)

Would an anti-sludge, if such a thing exists, additive for the tank be a good idea? Or should I just change filters after every trip for a while until they don't look like that? Or is it possible to clean the tank and lines?

Anyway, we'll take it for a ride to the "local" cummins guy tomorrow and get the codes read, but those filters needed to be changed, either way.

Just figured I'd post an update. :-)

Mark

(edit: Oh yeah... Seemed to take forever to re-prime. Per the Cummins guy I talked to, I filled the chassis filter with diesel before installing but installed the motor side filter dry. I assumed this would be better because there'd be at least one filter between raw diesel and the motor. Turned the key on and let the fuel pump run for thirty seconds or so a couple times, then fired it up. Started right up, ran for about ten seconds, then died. :-/ Did the re-prime thing a few times, tried again, nothing. Re-primed again a few more times, same deal. On the third time around I heard it trying to start and it fired up and ran fine. Is that normal? Or do I possibly have some weak fuel pumps?)

[st687]

Go to Napa and get an algicide and new filters, change filters as needed, if this does not correct the problem you will have to remove the tank and have it cleaned.

[marka]

Howdy,

Went to the 'local' Freightliner place... Freightliner of Bangor (Maine). They couldn't have been nicer... Super helpful and highly recommended.

Anyway, no issues driving the 50 milies each way to the place, the tech pulled the inactive codes, and they all related to fuel with the first step in all the diagnostic procedures was "check fuel filters"... :-) He was also able to scan and see that the reported fuel pressure matched the requested fuel pressure.

On his recommendation as well, I picked up some biocide / fuel conditioner and have it in the tank right now. I'll probably change the chassis side fuel filter again when we get back from this trip (another 800 miles or so), then just monitor.

Again, I can't recommend Freightliner of Bangor highly enough. They wouldn't even charge me for the diagnostics! At least I was able to buy some filters there to give them a little business... Prices were within a dollar or so of RVChassisParts.com as well.

Thanks for everyone's advice on this!

Mark

[rmmpe]

I, too, had a really great experience with Freightliner of Bangor. For the very same reason as you.