I may have to get someone to look at our ISL and our travels will take us thru El Paso after a week stay in Kerrville, TX. Anyone have any feedback on Cummins Rocky Mountain in El Paso? My coach is well out of warranty so would be fine with a good independent shop if they know their way around Cummins engines. I am having intermittent low fuel pressure events which cause loss of power. I have changed my fuel filters twice in the last 900 miles and problem goes away for a day or two then returns. I had this problem last year but my local Cummins shop could not duplicate it and said they thought I should just treat my fuel for algae, which I have done and continue to do.

Is the fuel in your filters black?read my old post, I've been fighting this for several years, my cummins is now having all the injectors removed checked for cracks, tested, re-sealed.my filters will clog at 10k miles (+-) but the first few times they would clog almost every day while traveling. it took 5 sets of filters to nurse it home from Tenn. in 2010. Algae must have water and sun light to grow, it is very rare that Algae will grow in a motorhome tank, but it can be pumped in.

Do you have a programer/chip on your 425 ISL?You maybe running too hard, over heating the fuel in the head as the return fuel is returning to the tank, this will cause Asphalting, and clog filters. Does you oil quantity go down as you drive. If so, you can have a leaking "O" ring that separates the oil from the return fuel in the head. Have your shop call Cummins technical get them involved, they will tutor the shop thru the repair process.Do not allow the shop start throwing parts at this problem, none of cummins injection pumps can cause this, and they are huge expensive. You either picked up a load of bad fuel, or have oil or combustion products getting into the return fuel. Have you ever seen any black jelly like substance in the filter cans when you change filters? (that would be algae )A loose injector will allow combustion products to enter the return fuel when combustion occurs. IT simply by-passes the copper gasket at the bottom of the injector, enters the return fuel.A leaking injector "O" ring will allow oil to enter the return fuel, but usually shows as high oil usage. Both will eventually clog a filter. quickly at first. -- ( that, I still don't understand)PM me for all we have done to cure our problem.

Might be a weak lift pump. Be careful if so because you can knock out the injector pump if pressure gets too low. I would want to put a gauge on pressure to see what it runs over time.

When you changed the fuel filters-- what did you find?

lc0338 wrote:Might be a weak lift pump. Be careful if so because you can knock out the injector pump if pressure gets too low. I would want to put a gauge on pressure to see what it runs over time.He has common rail system, it can not be a weak lift pump. it turns off after 3 minutes.

Cummins El Paso | Good Sam Community

smlranger
Explorer
Jan 25, 2016
RandandDoug wrote:
I had the same "sounding" issue a couple years ago, and it was a sensor on the fuel rail. Hope yours is just as easy.

Was the issue intermittent/unpredictable?
RandandDoug
Explorer
Jan 25, 2016
I had the same "sounding" issue a couple years ago, and it was a sensor on the fuel rail. Hope yours is just as easy.
smlranger
Explorer
Jan 24, 2016
artillery6 wrote:
We have used Rocky Mountain in El Paso and found them to be very professional and know what they are doing. I would recommend them.

Thanks. That is good to know. While I am hoping the diesel shop here in Kerrville can diagnose and fix the problem, it is good to know we still have a good option on our route west.
artillery6
Explorer
Jan 24, 2016
We have used Rocky Mountain in El Paso and found them to be very professional and know what they are doing. I would recommend them.
smlranger
Explorer
Jan 23, 2016
I understand the injector pump is very expensive. I would also be more inclined (unless the mechanic has proof/evidence of something else failing) to have them replace the fuel rail pressure sensor and switch.
moisheh
Explorer
Jan 23, 2016
Ray: a 559 code can be many different fuel problems . Could be the pump, could be the sensor, pressure switch, filter related and more. I saw on the Cummins computer a page or 2 of the possibilities. Cummins has a specific order to do the tests. Nothing is ever as simple as throw on a new pump. When I had them replace the switch and sensor I already had a $1500 bill. I simply told them to replace the 2 items. It worked.

Moisheh
Tom_Barb
Explorer
Jan 23, 2016
RayChez wrote:
Yea! code 559 is low fuel pump pressure. Might have to change out the fuel pump.

I'd certainly check the pressures with a direct reading gauge prior to committing to a new pump.
2gypsies1
Explorer III
Jan 23, 2016
Fiesta wrote:
To answer the OP. We lived in El Paso for 22 years. The service there was terrible. Too many across the border mechanics....
Make sure the person working on your vehicle is truly certified by actually looking at his/her credituals.

Are you talking about the Cummins facility? Their mechanics have specialized training.

Or do you mean the general repair shops?
RayChez
Explorer
Jan 23, 2016
Yea! code 559 is low fuel pump pressure. Might have to change out the fuel pump.
Fiesta
Explorer
Jan 23, 2016
To answer the OP. We lived in El Paso for 22 years. The service there was terrible. Too many across the border mechanics....
Make sure the person working on your vehicle is truly certified by actually looking at his/her credituals.

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