Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 12, 2025 ...

reduced power from isl400?

March 01, 2014, 02:39:22 am

Please help me figure this out.

Last summer, I has a resonator installed on my 2003 U295. At the time, I was having my service done, and the mechanic noticed the fuel pump was leaking, so putba new one in. He did not see a need to change the fuel filters.

My next outing, I noticed the engine seemed to be more responsive, but no faster going up hills.

A week later, it was very slow going up hills, and suspecting a fuel problem, I asked my mechanic to change the fuel filters. He showed me what came out of the filter when he cut it open, black sludge. I am niot sure if he changed one or two filters. I added fuel additives just in case something was growing in there, and went through two tanks full of good diesel.

After that it is faster on the hills, but I don't feel as fast as before. And of late, I feel it is getting slower again.

So, what is going on? Did he miss a filter, did it reclog? Is the fuel pump not delivering enough fuel, are my fuel lines going soft? Do I need to use a different mechanic?

Oh, and one thing that makes it hard for me to be certain, at the same time as this all started, I went from the coach alone to the coach towing a 4500 pound car.

Quote Selected

Re: reduced power from isl400?

Reply #1 – March 01, 2014, 07:37:47 am

I have the 400 engine as well 02 295.  I noticed a difference in going up hills moving from towing an HHR to the GMC Terrain.  The added weigh does make a difference.  I know a lot of people say they don't know the tow car is back there and that may be true on flat to short small hills but get on a 10 mile 6% grade up and you will notice it.  Tks DAN

Quote Selected

Re: reduced power from isl400?

Reply #2 – March 01, 2014, 08:22:26 am

With the discovery of algae, you need to do a couple of things:

Add a BIOCIDE (Biobar JF is a popular one and available at most marine stores).

Change both fuel filters (I have not seen a Foretravel with only a single fuel filter.  Make sure you use the correct micron-rating filters-- 10-30 micron for primary and 5 for secondary.

Keep an eye on the primary filter (assuming you have the clear bowel model).  Drain anything other than golden colored diesel (with engine OFF!).  Change filters (i.e. carry at least two sets of filters) if performance degrades or large amount of slime appears.

The biocide will keep the algae from multiplying, but the filters will have to remove their "dead bodies".

To reduce condensation in the tank (algae requires both water and diesel to grow), keep tank full when storing it and use a biocide if you won't be burning that tank of fuel for two months in the summer or three months in the winter.

Brett

Quote Selected

Re: reduced power from isl400?

Reply #3 – March 01, 2014, 10:43:56 am

Yep, fraid algae and their cousins are squatting and won't be evicted without a fight. I have seen shops routinely replace fuel tanks in many cases in Olds and Volvo. Yours is just going to take a dose of biocide and filters. Don't forget to change the generator filters (both) at the same time. A water interface is necessary for them to multiply so check the bottom of the tank with light and mirror and the "view port" on the bottom of your primary filter if it has one.

Get the filter changing procedure down so you can change, restart and be on your way without grinding on the starter. I like to do it with the engine/fuel warm especially in winter. Disposable gloves, gallon freezer bags and paper towels come in handy. I make sure all the air is out of the system before I restart.

Generator after you replace the filters: If you have a manual start switch on the generator, open the "T" handle valve (if you have one) and hold the switch down in the glow position. That will run the electric pump. There should be rapid clicks gradually slowing. When you close the "T" valve, the clicking should slow and then stop in a few seconds. You probably have a different model but hope this may be applicable.

When filters start to clog, it almost always shows up on hill when the engine is using more fuel. Just doesn't have the old power but does not necessarily run roughly or miss. Generator filter problems occur when pulling a lot of amps like with both ACs on. If the big engine is lagging, stop and idle it until it is running smoothly for a minute or two before changing filters. This will get the air out of the system and after the filter change, it will start easier.

Pierce

Quote Selected

Re: reduced power from isl400?

Reply #4 – March 01, 2014, 11:27:41 am

Thanks.

Your responses are pretty much as I surmised. I only used the maintenance amount of algae killer after having the filters replaced, it probably needs the shock treatment. Now would be a good time for that as the tank is just under a quarter full. So after the treatment, I will fill the tank with fresh diesel and have all the filters replaced again.

By the way, the reason I only used the maintenance treatment was because I has just had just gone through two tanks of fuel, so figured the algae was mostly gone. Sounds like unsound reasoning.

Quote Selected