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1989 P30: Runs fine when not pulling a hill..throttle..acceleration…

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My 1989 P30 chassis motorhome...
My 1989 P30 chassis motorhome has a 454, 4 bbl, auto trans. Runs fine when not pulling a hill. In most places a push on the throttle gets a downshift and higher rpm with decent acceleration. On hills the engine will not rev even if manually put into lower gear. Have replaced fuel filter on carb and on gas line. Have heard there might be another filter closer to tank, but have not see it.
Submitted: 8 years ago.Category: Chevy
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Answered in 1 day by:
7/6/2010
Chevy Mechanic: mobile-tech,
 replied 8 years ago
mobile-tech
Category: Chevy
Satisfied Customers: 831
Verified
Hello , my name is Joel

I have read your post , and will do my best to help.

Your description sound very typical of a fuel starvation problem , and since you have already replaced both fuel filters , I would suspect that your in-tank electric fuel pump is not working.
There is an electric fuel pump in your fuel tank that provides a low pressure boost of fuel to the mechanical pump on the engine.
Normally , there is not another fuel filter - unless the coach builder or previous owner installed one.

There is a relay and an oil pressure switch involved in the electric circuit - which could be at fault.
Below are a few drawings of the electric fuel pump circuit which may help you in troubleshooting.

graphicgraphic
I hope this information is of help.
Please let me know if you still have any concerns.

Thank you ,
-Joel
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