1997 F53 Motorhome Fuel Pump Mystery

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Old 04-02-2012, 11:31 PM
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1997 F53 Motorhome Fuel Pump Mystery

I have recently joined and already I have a strange problem I would appreciate opinions on.

In 2010, about 7000 miles ago, I had the fuel pump replaced with the new turbine style pump - by a Ford dealer.

Suddenly it won't start
Cranks strongly
There is spark at the coil and plugs.
There is no fuel pressure either at the fuel rail or the filter

The pump appears to be running ( can hear some slight noise even though the tank is full ). When jumpered at the Fuel Pump relay the pump draws 18 amps ( which seems rather high to me).
When the connector on top of the tank is disconnected it shows 0 amps draw when jumpered at the Fuel Pump relay. ( no short in the supply wire and I have checked the inertia switch - its OK ). The ground from the pump is good.
Pump also makes some noises when jumpered with 12 V at the connector on top of the fuel tank

The pump will "run" for 1 second when ignition is turned on and "runs" continuously when cranking ( as indicated by a test light tapped into the pump relay terminals), which is correct.

All indications are that the pump is getting the correct supply voltage and that it is running ( from its current draw and some noises in the tank ).

But no fuel is being delivered . How can this be ??

The only caveat being that the noises when it is running are slight and what sounds like fuel running/ dribbling inside the tank continues for a few seconds after pump goes off ( I initially took this to be the return, but it obviously isn't)

Thanks in anticipation, Peter




 
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Old 04-03-2012, 10:20 AM
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You either have a blockage between the pump and the fuel filter or a bad pump.

My guess is a bad pump.
 
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Old 04-07-2012, 05:12 PM
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Originally Posted by subford
You either have a blockage between the pump and the fuel filter or a bad pump.

My guess is a bad pump.
Subford knows I respect his diagnoses, and his knowledge of likely failures is better than mine. That all being said, if the fuel pressure regulator were to bypass ALL the fuel delivered to it, would that not match the symptoms described?

That might be an unlikely regulator failure mode, of course. And if the current draw is on the high side, that would point more towards a blockage.
 
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Old 04-07-2012, 05:48 PM
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If the FPR were bypassing all the fuel back to the tank the current draw would be low.
Sounds more like a locked rotor in the pump.
I think he hears a hum from the locked rotor motor.
Most Ford fuel pumps draw less than 4 amps.
 
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Old 04-09-2012, 09:40 AM
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Bad/faulty pump.
 
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Old 04-09-2012, 04:07 PM
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Bad news, and it always seems to happen with a full tank. Sounds like a locked rotor to me as well.
 
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Old 04-13-2012, 12:41 AM
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Its a BAD Pump

Got the fuel out of the tank OK using a small 12v low pressure fuel pump I had. Not difficult dropping the tank, used a tow strap through the two oval slots in the frame, to lower it
Took out the fuel pump module and applied 12 V to it, some slight noise but not "running"
Un-crimped the pump body and removed the bottom cover under which is the impeller / turbine. Motor then ran OK - but really don't know if its developing full power or not. Compared with a 12V rechargeable drill I have it sounded "weak".
It "appears" as if the impeller blade tips may have been catching in the slot which they are supposed to pump fuel out through,
Oh, I did blow through the line and gas flowed out at the filter connector - so it wasn't blocked.
I haven't had much luck finding a pump on Vancouver Island so have ordered an Airex E2521 from Rock Auto.
I also intend to install another outlet line in the pump module top plate and use it to supply an external pump down by the filter - to be used if I have another failure. I'm aware that this line will have to be full of gas as the pump isn't positive displacement and won't "suck".
Must saw I'm disappointed in this "new turbine style Ford Pump" which lasted only just over 1 year and 7,000 mile.
Thanks for the help
Peter
 
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Old 04-13-2012, 06:54 AM
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Yes the E2521 will work and is the right one to replace the pump for turbine style pump.
 
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