ISL not performing

Wix might be OK for a gas engine but I would not use them on a large diesel. They often do not have the same micron rating as OEM. They also use a different method for establishing the rating. For a Cummins stick to Fleetguard.

Moisheh

Ivylog wrote:
It's surprising how much junk you can get out of a filter before it starts restricting the fuel flow. Yes, I've been known to clean one out by shaking it and then putting back on when I did not have a spare one handy.
Assuming your guy put fuel in the filters, there is no way that small amount of fuel is going to clog the filter regardless of how dirty.
Thanks for the update although it's still a mystery why the filters caused the problem. Two expensive filters is still cheaper than a visit to a shop. I would put one back on at a time to see which one was the problem and then cut it open to see if there is a obvious problem, but I like mysteries and the smell of diesel on my hands.

Ivy,

I seriously doubt that I have more experience than you when it comes to Diesels but, over the years I had more than just a few filters that were dropped/bent/dented, had o ring cut or just a little dirt on the o ring causing the same problem, bad seal/air into the fuel, so we could look at it for hours and never find the problem. So just do the simplest thing first, new filters.

The best thing here is that the OP reported back and we are all just a little smarter.

Other than water in the fuel I have never had a filter not pass fuel, so I'm pretty sure it was a bad seal/air in the line that caused a loss of power under load.

I Hate Mysteries and nothing worse than the smell of Diesel on MY hands, on Your it smells great, but on my hands NO WAY.

JMHO,:B :B :B



















JMHO,

It's surprising how much junk you can get out of a filter before it starts restricting the fuel flow. Yes, I've been known to clean one out by shaking it and then putting back on when I did not have a spare one handy.
Assuming your guy put fuel in the filters, there is no way that small amount of fuel is going to clog the filter regardless of how dirty.
Thanks for the update although it's still a mystery why the filters caused the problem. Two expensive filters is still cheaper than a visit to a shop. I would put one back on at a time to see which one was the problem and then cut it open to see if there is a obvious problem, but I like mysteries and the smell of diesel on my hands.

Both NAPA filters looked OK when we took them off and nothing untold came out when we dumped their contents into a pan. They did have slightly different "o rings" or seals (the loose ones that come in the package), but otherwise looked pretty similar to the Fleetguard ones we installed. The guy helping me also knew they were made by Wix and thought they were usually of pretty good quality. I was a little suspicious when I purchased the Fleetguard filters and found out they were almost twice the price of the NAPA ones. Maybe you do get what you pay for. The other thing I wondered about was the quality of the diesel fuel the guy who changed them last winter used to fill or prime them. If it was old or dirty, perhaps he clogged the filters with it right at the install.

rad1 wrote:
OK, changed out the Napa fuel and fuel/water filters this evening for the correct Fleetguard ones and all seems back to normal.

That could be for quite a number of reasons.

The NAPA filter could have been exactly the correct one and just clogged up.

The NAPA filter could have been an incorrect filter-- not fitting properly on the housing or wrong micron rating (like a 2 micron used as a primary filter).

The NAPA filter could have been improperly installed (wrong or no center seal/gasket.

And, yes the NAPA filter could have been defective.

Thanks for the follow up. It made sense that it was a fuel filter problem and glad it was that simple a fix. I use NAPA filters on my ISL so there has to be a defect or improperly installed problem. Did you see/find anything that might explain why you had a problem with the NAPA filters?
Last year I had a little worse power/fuel problem which changing the fuel filters and the lift pummp $$$ did not solve. Here is a link to that adventure and education for those with Cummins engines.

Good to hear its back to normal.

Wix makes NAPAs filters last I knew, and they're a good filter. Obviously something went south somewhere along the line in this one.

Thanks for the update and enjoy the ride.

Glad you got her fixed...find your 'friend' that changed your filters and give him the Donald Trump wave..."You're Fired"!..:B

Thanks too, for taking the time to post your result...

OK, changed out the Napa fuel and fuel/water filters this evening for the correct Fleetguard ones and all seems back to normal. Went for a 20 mile ride and the engine pulls like it used to and the transmission now shifts up over 2K, where it used to. Thanks to my son and his buddy who has a diesel truck for their help and for all the forum members who helped diagnose the problem. I've never posted a question here that someone hasn't had either the answer to or at least a good place to start. You guys are the best.

I want to thank all of you for your thoughts on what might be causing the lack of performance with my coach. I too leaning towards a fuel delivery issue, but I have no hands-on experience with diesel engines.

Just to address a couple of the questions posted as well. My coaches (old diesel and this one) always sit for 2 or 3 months while we're down in FL for the winter. I always make sure they are full of fuel before we park and I drove about 50 miles after the last fill up prior to parking. I have to believe the cause has something to do with the oil/filters changed by the local guy while we were parked, since nothing we did this past winter was any different than that done every other winter. I always fill up at the truck stops (Pilot/Flying J) to try and insure getting fuel that at least has a good turn over and isn't old due to nobody filling up. That doesn't mean it's impossible to have gotten some bad fuel, but I did drive 50 miles on the last fill up with no issues. I also drove home some 1200 miles with this issue, so I had several fuel stops since, with no change in the way it runs.

I've just come back from my local diesel service center with the proper Fleetguard fuel and fuel/water separator filters (after a call to Cummins to verify the numbers)...and some diesel fuel to prime them. I just got out from under the coach and everything is clean as a whistle, no leaks or anything anywhere. And both filters feel tight. I plan to replace the filters on the coach (Napa versions) in the next couple days with the Fleetguard filters I just purchased. I'll post an update after the change out. Thanks again.