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The Driver · 04-24-2014, 05:26 PM

My 2006 ISM 500hp engine will "derate" or lose power with reduced turbo pressure above 1400 rpms only after at least an hour of steady driving when the outside temp is above 50 degrees.

No check engine light ever comes on (Cummins checked, and it's working properly and no fault codes were stored).

We finally got it to a Cummins shop when it was experiencing the problem, and they found reduced fuel pressure out of the only fuel filter on my coach. Same test had been run by another Cummins shop while engine was cold, and no drop in pressure.

Pulled the fuel filter and found quite an accumulation of stuff: some looked like small flakes of rust, some seemed a bit like gel, and some seemed a bit greenish like algae.

Put on new filter and ran the coach on the nearby interstate almost flat out for 45 min....and maybe felt a tinge of hesitation at high revs with a very slight reduction in boost pressure. Pulled new filter and found a slight amount of same "rust flakes" as before. Put on another new filter.

Even if this fixes the problem, I don't understand why it would only trigger after the engine compartment really warms up. We ran the WVa mountains on a 40 degree day without one hickup last week.

palehorse89 · 04-25-2014, 06:06 AM

After reading your post Doug, is it possable that you picked some bad fuel? sounds like your problems is lack of fuel getting to the engine and you are finding your filters about plugged off...........Maybe a tank drain and flush is in order.........or just keep spare filters on hand.

Rick & Hope · 04-25-2014, 06:16 AM

Did you fuel with Bio Diesel? That will clean your system of all the junk built up and plug your filter.
Has your MH sat for an extended period of time. If so you may have algae growing in the tank.
Just some of the problems we have run into with the semi's over the years.

The Driver · 04-25-2014, 07:06 AM

All kinds of possibilities for the source of the filter debris, but I don't understand why the derate occurs only after a very thorough warm-up...and it seems like understanding that point might help narrow the search for the source.

spinn · 04-25-2014, 09:21 AM

Quote:

Originally Posted by The Driver

All kinds of possibilities for the source of the filter debris, but I don't understand why the derate occurs only after a very thorough warm-up...and it seems like understanding that point might help narrow the search for the source.

Just a thought Driver, but after driving a while the fuel could be getting stired up enough to start pulling it into the pickup tube?
Steve

palehorse89 · 04-25-2014, 10:00 AM

The fuel is cold when first started, and after running, the "fuel return" to the tank is warmed, quite a bit. Not sure to what temperature. If you were to feel your tank after running a while you would feel it to be warm, and with the fuel return going back to your tank.......Might be stirring it up as mentioned above......
I believe me and the others understand what you posted, but as always, when trying to help with a problem, when just reading of what the problem is, and not there to experience it or see what is actually going on, alls folks can do is offer their best suggestions. Your filter condition seems to point to contamination in your tank for sure. Did you actually cut the filter apart at the top ring and remove the outer part so you can see the paper media and what is on it? or in it, or are you just looking inside the center hole? I cut mine apart every change to inspect the media to see exactly what is on it.

The Driver · 04-25-2014, 10:02 AM

Quote:

Originally Posted by spinn

Just a thought Driver, but after driving a while the fuel could be getting stired up enough to start pulling it into the pickup tube?
Steve

Hmmm, makes sense...

Genset · 04-25-2014, 10:06 AM

Would be thinking EGR, they have had issues, Cummins now claims they have it solved, but the issue sure affects many ISM with the EGR.

DAVE M

palehorse89 · 04-25-2014, 10:08 AM

Quote:

Originally Posted by palehorse89

The fuel is cold when first started, and after running, the "fuel return" to the tank is warmed, quite a bit. Not sure to what temperature. If you were to feel your tank after running a while you would feel it to be warm, and with the fuel return going back to your tank.......Might be stirring it up as mentioned above......
I believe me and the others understand what you posted, but as always, when trying to help with a problem, when just reading of what the problem is, and not there to experience it or see what is actually going on, alls folks can do is offer their best suggestions. Your filter condition seems to point to contamination in your tank for sure. Did you actually cut the filter apart at the top ring and remove the outer part so you can see the paper media and what is on it? or in it, or are you just looking inside the center hole? I cut mine apart every change to inspect the media to see exactly what is on it.

Flushing your tank out might be less expensive than a ton of filters and maybe changing them on the side of the road.......

Quote:

Originally Posted by The Driver

Hmmm, makes sense...

The Driver · 04-25-2014, 10:10 AM

Quote:

Originally Posted by Genset

Would be thinking EGR, they have had issues, Cummins now claims they have it solved, but the issue sure affects many ISM with the EGR.

DAVE M

No fault codes, and EGR shows good function when hooked to Cummins computer while hot or cold.

The Driver · 04-25-2014, 10:39 AM

Quote:

Originally Posted by palehorse89

The fuel is cold when first started, and after running, the "fuel return" to the tank is warmed, quite a bit. Not sure to what temperature. If you were to feel your tank after running a while you would feel it to be warm, and with the fuel return going back to your tank.......Might be stirring it up as mentioned above......
I believe me and the others understand what you posted, but as always, when trying to help with a problem, when just reading of what the problem is, and not there to experience it or see what is actually going on, alls folks can do is offer their best suggestions. Your filter condition seems to point to contamination in your tank for sure. Did you actually cut the filter apart at the top ring and remove the outer part so you can see the paper media and what is on it? or in it, or are you just looking inside the center hole? I cut mine apart every change to inspect the media to see exactly what is on it.

Double hmmmm....the fuel return stirring the tank....that's fascinating.

My filter is open on the bottom, where a clear bowl screws on for water separation, so can reach up into filter folds.

tom chelbana · 04-25-2014, 04:21 PM

You have a drain on the bottom of the tank and I would suggest you get a container and drain a gallon of diesel out and look at it. The worst should be at the bottom of the tank.

The Driver · 04-25-2014, 04:49 PM

Quote:

Originally Posted by tom chelbana

You have a drain on the bottom of the tank and I would suggest you get a container and drain a gallon of diesel out and look at it. The worst should be at the bottom of the tank.

I lead a charmed life, Tom. I was on the phone today with Chris at the Spartan factory about my appointment there next week, and he mentioned the drain! I might try to open it before my appt there...after the coach has sat over this weekend.

Good tip, thanks!