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10-31-2017, 11:44 AM
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#1
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Junior Member
Fleetwood Owners Club
Join Date: May 2017
Posts: 24
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94' 37ft bounder f53 ford 460 fuel pressure problems
As my title says I am having fuel pressure problems. New fuel pump assembly (not just pump), fuel filter, Fuel pressure regulator, plugs, wires, rotor, coil, throttle position sensor, and water temp sensor (on top of the block). I have deleted and blocked off EGR. Disconnected and block the gas vapor vacuum.
At idle I get 32-35psi at the fuel rail at idle and can go WOT in park and get about 40 psi.
Now the problem starts. I start to drive and she goes great for about 10 minutes. Responsive all the way through the throttle positions from top to floor then at some point she will bog down and fuel pressure drops. Last night went down to 10 psi. I will also get a backfire. At this point I have to feather the throttle to get any acceleration. If I turn off then back on she is good for another few minutes then the cycle starts back all over again.
Cool temps in the 50’s-60’s and about ¾ tank.
Feel free to call or email.
404-441-7812
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10-31-2017, 03:02 PM
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#2
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Senior Member
Winnebago Owners Club Ford Super Duty Owner
Join Date: Jul 2012
Location: Where the Rig is Parked
Posts: 1,393
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It almost sounds like some part of the fuel line is getting too hot and creating vapor lock. Is the timing OK
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10-31-2017, 05:04 PM
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#3
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Senior Member
Join Date: Mar 2009
Posts: 1,700
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I suspect a high resistance circuit. Gets hotter the longer you drive and drops the voltage to the fuel pump. Maybe the fuel pump relay in the fuse/relay box under the hood. When you turn off the engine and restart, you exercise the relay contacts. Just swap it with the horn relay and give it a try. Also the inertia switch on the left side of the steering column could be a problem.
Vapor lock is pretty much a thing of the past with pressurized fuel lines.
Richard
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11-01-2017, 07:25 AM
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#4
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Senior Member
Join Date: Aug 2008
Location: Austin, TX
Posts: 393
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Quote:
Originally Posted by RHellen
As my title says I am having fuel pressure problems.
I have deleted and blocked off EGR.
404-441-7812
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As Richard says, fuel pressure depends on getting the correct electricity supply to the pump, the pump working, the flow being unimpeded, and the pressure being correctly regulated. You've done most of those, so it seems time to monitor voltage at the pump, and possibly also current to the pump.
On your EGR mods, if you haven't changed your ECU or the code in your ECU, then you haven't deleted EGR, you've just disabled it. What you still have is the advanced ignition timing that EGR needs to work, and without any EGR happening, you'll have too much timing. On our engines, EGR is an economy device, worth keeping.
Michael
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11-01-2017, 07:35 AM
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#5
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Registered User
Ford Super Duty Owner
Join Date: Nov 2014
Location: NW Ohio
Posts: 7,114
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Two thoughts
1) does the fuel regulator have a vacuum line connected to it? If so, disconnect it and see what happens..
2) Remove the fuel fill cap, this will make sure the fuel tank is breathing and not pulling a little vacuum.
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11-01-2017, 04:46 PM
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#6
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Junior Member
Fleetwood Owners Club
Join Date: May 2017
Posts: 24
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Quote:
Originally Posted by Waiter21
Two thoughts
1) does the fuel regulator have a vacuum line connected to it? If so, disconnect it and see what happens..
2) Remove the fuel fill cap, this will make sure the fuel tank is breathing and not pulling a little vacuum.
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rh
1)it does. Do this while driving?
2)did the fuel cap thing and it did not help but I was thinking the same thing
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11-01-2017, 05:09 PM
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#7
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Junior Member
Fleetwood Owners Club
Join Date: May 2017
Posts: 24
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Quote:
Originally Posted by mpaton
As Richard says, fuel pressure depends on getting the correct electricity supply to the pump, the pump working, the flow being unimpeded, and the pressure being correctly regulated. You've done most of those, so it seems time to monitor voltage at the pump, and possibly also current to the pump.
On your EGR mods, if you haven't changed your ECU or the code in your ECU, then you haven't deleted EGR, you've just disabled it. What you still have is the advanced ignition timing that EGR needs to work, and without any EGR happening, you'll have too much timing. On our engines, EGR is an economy device, worth keeping.
Michael
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RH
top response: voltage i get, OHMS kinda, but current? Is that amps? Kind of ties into what Richard said and something dropping power to the pump. Not sure how to monitor other than to createseom long a** probes.
bttm response: on the egr. This was not intentional but tube broke in half but then the bottom fitting broke off at the block and I had no way to grip the fitting to get it out. See picture and the smooth hole at the bottom of the tube. That was attached to the block. It almost looks like a prssure fitting. I have access to welder so I can re-attach if needed. Iread on another thread to tape a wire nut to the sensor to keep it partially depressed so the CE light does not come on. Timing: Are you saying I need to back the timing off back towards TDC? Top Dead Center?
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11-01-2017, 05:17 PM
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#8
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Junior Member
Fleetwood Owners Club
Join Date: May 2017
Posts: 24
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egr assembly
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11-01-2017, 05:21 PM
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#9
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Junior Member
Fleetwood Owners Club
Join Date: May 2017
Posts: 24
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I have been told the timing "sounds" ok from an old school Ford guy but we could not get the distributor bolt loose so we could not adjust. I have a light but have not tried it.
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11-01-2017, 05:53 PM
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#10
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Junior Member
Fleetwood Owners Club
Join Date: May 2017
Posts: 24
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I have seen the posts about the inertia switch/relay and will look at that and the pump relay. Got to find 'em now. Dumb question but does the inertia switch have a mechanical mechanism that could move by "punching" the throttle?
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11-02-2017, 12:00 PM
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#11
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Senior Member
Join Date: Mar 2009
Posts: 1,700
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Quote:
Originally Posted by RHellen
I have seen the posts about the inertia switch/relay and will look at that and the pump relay. Got to find 'em now. Dumb question but does the inertia switch have a mechanical mechanism that could move by "punching" the throttle?
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No, the inertia switch goes open on impact to stop the fuel pump. There is a reset button on the switch.
Do the easy stuff first. Swap out the fuel pump relay with the horn relay. Both in the black plastic box under the hood.
Richard
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11-02-2017, 03:27 PM
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#12
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Senior Member
Join Date: Aug 2008
Location: Austin, TX
Posts: 393
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Quote:
Originally Posted by RHellen
RH
top response: voltage i get, OHMS kinda, but current? Is that amps? Kind of ties into what Richard said and something dropping power to the pump. Not sure how to monitor other than to createseom long a** probes.
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Yes, current is measured in amps. Making long wires that go from the connector at the top of the tank to somewhere that you can attach a meter would work. If you have good voltage at the pump, then the current SHOULD be fine.
Quote:
Originally Posted by RHellen
bttm response: on the egr. This was not intentional but tube broke in half but then the bottom fitting broke off at the block and I had no way to grip the fitting to get it out. See picture and the smooth hole at the bottom of the tube. That was attached to the block. It almost looks like a prssure fitting. I have access to welder so I can re-attach if needed. Iread on another thread to tape a wire nut to the sensor to keep it partially depressed so the CE light does not come on. Timing: Are you saying I need to back the timing off back towards TDC? Top Dead Center?
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Bottom fitting goes into the exhaust manifold. If the timing is correct, then it isn't worth changing it. Computer controlled ignition timing is way more complex than a simply curved distributor. Even your old school guy could probably hear pinging when EGR is called for and advanced timing is output, but this isn't close to all the time. Just light throttle cruise. You may never do light throttle cruise in a 37 footer.
If you might replace the tube, look into a Ford service which would supply a new insulated tube that is curved to avoid house bodywork so it doesn't set it on fire. That could get you a new tube for free. Sorry I don't remember the number, but my own '94 F53 still gets mail from Ford about it.
Michael
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11-04-2017, 09:50 PM
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#13
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Junior Member
Join Date: Aug 2017
Posts: 4
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I suppose that you have checked the fuel line filter, had a problem like you described.
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11-04-2017, 10:00 PM
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#14
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Junior Member
Join Date: Aug 2017
Posts: 4
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F 53 mechanic near Somerset Kentucky
I have an apparent fuel pump problem. MH is in a storage building. I need a mechanic and probably a tow truck. I've had Good Sam towing for over 11 years but they will not help.
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