LRGTENT
California
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Joined: 04/13/2007
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Here's a bizarre scenario for all you techs out there.
We have a 96 Bounder on an F-53 chassis. The 460 engine often bogs down while driving, usually when we encounter a grade. Sometimes it happens on flat roads. If I shift to neutral and turn off the ignition (dangerous, I know) then restart, everything is fine.
We have had the fuel pump replaced several times but had it checked anyway. Shop said fuel pump waveform is good. Fuel pressure regulator has also been replaced.
Anyone have any ideas? Any help would be much appreciated.
1996 Bounder F53
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Dick A
Spokane
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You mentioned you have had the fuel pump replaced "several times"?? It is well documented the original in-tank pump used during the early & mid 90's was a problem but the replacement current model should last a long time.
Has the fuel filter located along the chassis rail been replaced recently?
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Big Katuna
Deland, FL
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Joined: 12/27/2003
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I recognize the symptoms; sounds like the in-tank fuel pump. I don't understand why the fuel pump should have to be replaced several times. At $700 per incident, I would have torched the coach by now. The factory pump was a diaphragm type and they ALL need to be replaced with a turbine style pump. ONCE! I also don't know what "fuel pump waveform" means. The pressure as read at the OBD port should be in the high 30's, low 40's.
My Kharma ran over my Dogma.
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calicoupl64
castroville,calif.usa
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Joined: 10/15/2004
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have the catalytic converter checked,I thought it was the fuel pump to but my cat was plugged and eventually just shut the motor down.
92'gulfstream sunsport
F53 460fi 
big gas tank,small holding tanks 
3 honda dirtbikes in tow.
Quote:"My wife doesn't drive the RV,She just tells me how to" 
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Bruce Brown
Northern NY
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Joined: 06/01/2001
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calicoupl64 wrote:have the catalytic converter checked,I thought it was the fuel pump to but my cat was plugged and eventually just shut the motor down.
Good advice. Also keep in mind there are sometimes 2 fuel pumps; the one in the tank and another on the frame rail. Ask me how I know. (And how easy it is to change sitting in a parking lot) 
There are 24 hours in every day - it all depends on how you choose to use them.
Bruce & Jill Brown
2008 Kountry Star Pusher 3910
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The_Vintagers
Georgia USA
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Joined: 06/22/2008
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and fuel FILTER
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Big Katuna
Deland, FL
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If turning the ignition off then back on corrects it temporarily, it still sounds like a fuel pump or low fule pressure. I did the same thing all the way back to Florida. I wouldn't think a clogged CAT would do that.
I think if there is a second fuel pump on the frame rail, someone added it aftermarket. There wasn't one there stock. Some folks did that instead of replacing the in-tank. There are several threads here on the forum regarding doing that.
A decent shop should be able to connect a portable OBD diags device or a fuel pressure guage to the fuel line and monitor the pressure while driving.
Did it do it when you had a full tank of fuel or get worse when the tank got to about half?
Keep us posted.
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Hikerdogs
Wisconsin
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Joined: 08/23/2004
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I had a similar thing happen on my 1995 Ford Bronco with a 351 engine. It started out bogging down only on a grade. Over time it got worse, and eventually would hardly run at 50 mph on the straight and level. It turned out to be an internally collapsing muffler.
Have someone listen to the noise from the tailpipe when you momentarily step on the gas hard. If the noise from the tailpipe sounds like a jet trying to take off it's probably a restriction somewhere in the exhaust system.
Disassemble the system at the rear of the catalytic converter. If there's still a problem the converter itself is probably plugged. If you get good performance with it disassembled it's either a collapsed pipe between the converter and the muffler, the muffler, or the tailpipe.
Hikerdogs
2001 Winnebago Adventurer
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topflite51
In The Desert of Nevada
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Joined: 05/13/2004
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Can't remember if the OBD I system checked fuel pressure. I believe also that a '96 is a non CAT system. Have a good fuel pump pressure gauge connected and drive it.
When you say it is fine after the restart, do you mean until the next hill or until you have to restart after being shutdown for a period of time?
I also don't understand the " replaced fuel pump several times" statement. Did you misspeak and mean the fuel filter?
It sure sounds like an intermittent fuel pump problem to me, hard to diagnose sitting in the repair bay.
David
Just rolling along enjoying life
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decan9
Oceanside, CA
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calicoupl64 wrote:have the catalytic converter checked,I thought it was the fuel pump to but my cat was plugged and eventually just shut the motor down.
F53's in mid 90's did not have catalytic converters!
Bonnie and me and Casey makes three!
Staying warm in Southern California
FMCA #402157
W9NCR
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