POSSIBLE FUEL FILTER FOULED?

[LEAH DRAPER]

I have been experiencing some problems when starting  up a slight incline.  I first noticed it in traversing a rainy pass thru Utah mountains.  Since it was raining heavily I thought the perhaps the drive wheels were slipping.  After arriving home, I had the codes checked (at Allison dealer) and there were no codes indicating a problem.  As I left NM for AZ I again experienced the problem.  If on the level, there were NO problem, but the slightest incline would bring back the "slipping feeling" or bucking and the power would drop.

I am NOT a mechanical person being female, but I am also somewhat "more" savey than many women.  

I am beginning to think that I may have "dirty" fuel filters.  Is this a plausible explanation for what I am experiencing?
 

Gerald, I need your expertise please.

[Lloyd Hall]

I am not as sharp as Gerald on diagnosing these problems, however, I did have the same experence with my coach and it was the fuel filters. I changed them and put in new filters and it solved my problem.

Lloyd Hall

[Bill Sprague]

I paid a Cummins shop $600 for trouble shooting a rough runner with laptops and codes.  Oddly, the ATC light would flash when it missed a beat and that was confusing them.  Finally, a "good 'ole boy' blurted out, "Just change the *%X&n filters."  It has run well ever since and the ACT light quit flashing.  For the $600 they found a code saying the fuel pump had not been delivering enough fuel so the engine had to "de-rate".  The pump could pull enough fuel through the filters for the de-rated state, so it would decide to lurch back to "normal".

On the first sign of trouble, change the fuel filters!

I now have spare filters sealed in plastic, a couple strap wrenches and think I remember how to do change them.  If I forget, I'll call Marty for coaching.  

[Bill Sprague]

"I am NOT a mechanical person being female...

The most complicated machines in our 44 years of marriage are the sewing machine and embroidery machine.  Those are decidedly female and overshadow any complexity in a motorhome, drill press or table saw.  

It may be true that females are smart enough to avoid grease and oil.  Even smarter when they use their sly ways to convince the men to get greasy!

Spin on fuel filters are only slightly more complicated than spinning off the lid to a jar of peaches.  

Change those filters Leah!

[Joel Ashley]

Lloyd and Bill are right, Leah.  As long as your fuel tank isn't perilously low, the most likely cause of power loss only on inclines is that you are calling for more power, and therefore more fuel flow, which can't get through dirty filters in amounts adequate to the job.

Joel

[Gerald Farris]

Leah,
Like the others that have responded to your question, I think that the highest probability for the cause of your problem is a restricted secondary fuel filter. The primary filter is a 15 micron filter in most cases (some are even a 30 micron), so it filters out the sticks and leaves, but since it is much less restrictive than the 2 micron secondary filter it does not restrict fuel flow near as often. Therefore I normally only change the secondary filter, however it is only about 15 or 20 dollars more to be on the safe side and change both filters.

Gerald

[Glenn Perkins]

Leah,

I have to also side with the conventional wisdom here ... the filters are likely the culprit ... having had a similar experience coming west from a fuels stop in Amarillo and encountering a significant loss of power in Tucumcari NM.  Not carrying spare filters then, I found a shop open that immediately changed out the filters and all was well.  Believe I may have gotten some bad fuel in Amarillo ... or it may have been as a result of a winter in FL humidity too.

Good luck.

Glenn

[LEAH DRAPER]

Hey guys
Thank you so much for your input on this issue.  I guess I'll go get the proper filters and see if I can find some one to change them or try myself.  

Is there any thing I need to be aware of if I try to do it myself.  What about any fuel that may leak out, or will that happen?

Leah

[Bill Sprague]

Hey guys
Thank you so much for your input on this issue.  I guess I'll go get the proper filters and see if I can find some one to change them or try myself.  

Is there any thing I need to be aware of if I try to do it myself.  What about any fuel that may leak out, or will that happen?

Leah

I have a Cummins, so experience may vary!

Marty helped me change filters a little over a year ago when the fuel tank was full.  A quart or so siphoned out and there was a quart or so in the filters themselves.  When I changed them a few weeks ago, the fuel tank was around 1/4 full and there was no siphoning at all.  (The Cummins version has two filters.)  A standard bucket below the filters works fine.  

After you put new filters on, there is air in the system that has to be purged before you state the engine.  The Cummins version says you turn the ignition key on 4 times to let a "lift pump" purge the system of air.  Some installations have a manual pump at the filters.  Although my Cummins book says not to pre-fill the filters, I've seen mechanics do it.  The trick is to pre-fill the outside holes, because the engine draws from the inside hole.  The mechanic said he used recently filtered fuel to do the pre-fill the filters and then ran he ran the lift pump.

Any truck repair shop, truck stop service bay or truck dealer can do this easy.  And, they have a way to get rid of the fuel and old filters.

[LEAH DRAPER]

Thanks Bill, I think I will NOT try this my self.  Best I go get them serviced.

Appreciate your input, thanks again.

Leah