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Discussion Starter #1
Need some help on this one, here is the scenario. Installed blue spring, primed fuel system and truck fired right up w/out issues and no leaks. Let it run while I cleaned up my mess (10min), then drove 8 miles into town to fuel station. Filled tank with truck running, ran through car wash, then truck dies when pulling out. Checked fuse for fuel pump and it popped. Installed new fuse and truck fired right up. Assuming just a bad fuse I take off to the house. Get about 1/4 mile from him and she starts to stumble and dies again, won’t restart. Fuse and inertia switch good. Pump not kicking on, but power to plug based on test light check.
Assuming pump failed, I drag it to the house. Pulled pump and installed a replacement pump from O’Rielly in the HFCM housing. Noticed some junk and a little white wax looking substance in housing. Cleaned all that out. Cycle key to prime and truck fired up. Let it idle and within 10min it starts stumbling and dies. Run through same checks again and pump isn’t working despite power to plug. Remove, warranty replace and install new pump and it dies in 10-15min also.
Out of time today to work on it, but would love some help to point me towards probable causes of the continued pump failures as this has me stumped.
 

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O-rileys is my guess
I would only use a Parker / Racor = OEM motor for 99 bucks
or even a whole 300$ Parker / racor HFCM since there are non-serviceable parts inside the housing

other than that check the suction/ tank side for easy flow


I always like to think about things that were new before the issue
seems like for you it was fuel and blue spring

Are you sure the fuel was good and filters clean ( OEm filters now use a hydro block and do not bypass when clogged like the older version) and do you monitor fuel psi ?
 

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Discussion Starter #3
Forgot to mention, pump was replaced about 1500 miles ago with fresh MotorCraft filters. Put new MotorCraft filter on when I did the 1st pump last night. Old filters still looked clean, but replaced them anyway based on the wax looking white junk I found. No FP gauge currently, cheap glowshift job that was on truck when I bought it has a bad sender that I need to call and replace. Only change before this pump issue was the blue spring install.
 

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Fuses only blow when the current is excessive.

With the continuing issue, while you checked for voltage presence, you didn't check what the voltage was. A lowered voltage will cause a higher amp draw, which is what blows fuses.

There are three ways for this to happen, poor pin connections through the harness, poor ground connection, or poor relay contacts. There are multiple connections for this circuit, at the CJB, at the inertia switch, usually two in the harness under the master cylinder, at the harness by the pump, and at the pump. The ground for the fuel pump is on the firewall above the master cylinder area with two wires.

The bigger problem saved for last is the fuel pump relay. For reasons I can't imagine, he fuel pump relay is soldered into one of the boards of the CJB. The typical repair is to buy a new CJB ($350-400) or sent it out for repair ($150). The DIY solder-in doesn't have a good success rate due to the multiple pins that have to be worked to get to the relay properly.

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G100 is the fuel pump ground, along with others.


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And I forgot to add, to complicate it more, the PCM grounds the fuel pump relay to turn it on. It would not affect the voltage to the pump however.
 

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A voltage check at the pump connector with a new plugged in would be good -- lets see what is being delivered to the pump

The pump motor is cooled by the fuel flowing thru it, there could be air in the system or the return flow may be blocked
the pump can output about 100 psi and the blue spring should be abour 70 psi, but if something is wrong with the spring installation, the pump could be on internal relief all the time while re-circulating the same fuel over and over = hot pump
 
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The recirculating is not 100%, they were trying to avoid the overheat, but nothing is 100% when there are other factors, so a valid point.
 

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Discussion Starter #8
Sorry for the delayed responce and thanks for the suggestions. Heading out to go try and solve this dilemma again now. Will let you know what I come up with.
 

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Discussion Starter #9
Ok, double checked blue spring and everything looks correct there. No fuel leaks. Pulled plug from HFCM and read voltage key on, 11.88-11.94V during prime. Dropped to 11.47V after 20sec prime. This tells me I am getting proper voltage to pump, correct.

would the plunger in regulator not being seated right during blue spring install cause a lack of return if it couldn’t pop-off? Wouldn’t that lack of return cause the pump to then get hot?
 

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Discussion Starter #10
About to mount the brand new HFCM that I got from Ford this morning. Just want to be sure everything else checks out before plugging it in. Don’t feel like cooking a $500 pump.
 

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You would need to read the voltages with the plug in place by back pinning the connector for the readings to be meaningful
yes, the fuel flow is what cools the pump motor, so there has to be some return flow for this to happen

Would be a good time to re-locate the HFCM to behind the transfer case -- unless you do not have a 4x4
 

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Ok, double checked blue spring and everything looks correct there. No fuel leaks. Pulled plug from HFCM and read voltage key on, 11.88-11.94V during prime. Dropped to 11.47V after 20sec prime. This tells me I am getting proper voltage to pump, correct.

It tells you are getting proper voltage without a load. You need to back probe from the pump connector and see what the voltage is with the pump running.

would the plunger in regulator not being seated right during blue spring install cause a lack of return if it couldn’t pop-off? Wouldn’t that lack of return cause the pump to then get hot?
Is that what you found?

Jammed, the fuel pump would pump up to 100psi when it's internal relief valve would pop off, recirculating the fuel within the pump, but not flowing fuel through the motor itself to keep it cool as Hydro warned.
 

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Just one more reason to have a fuel pressure gauge installed on the truck
banging my drum again -- fuel gauge - fuel gauge - fuel gauge
 

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Discussion Starter #14
I hear you on the fuel gauge, waiting on glowshift to warranty the sensor unit for the one installed on the truck. New Ford HFCM is installed now And with return from engine unhooked I am getting circulation back to housing. See no leaks under pump pressure at regulator/upper filter housing. Let me see if I can get a reading KO with pump plugged in.
 

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The same wire you previously got ~12v, pink with a black stripe wire? Within the 20 seconds of Key-On? The pump should not be pumping anything with that.
 

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Discussion Starter #17
Just proved again. Getting 1-1.5v on that wire and meg lead to ground. Pump is running entire time, then shuts off at 20sec.
 

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I would not be running it for too long at that voltage, but next, I would check the voltage at the inertia switch at the passenger foot panel. My service manual calls out a different color than the green with a yellow stripe from the fuel pump relay, but Key-On for a quick reading is what I would check. If the voltage is still low there, you've got an issue with the fuel pump relay contacts. The pink-black goes through several connections to the fuel pump. Somewhere you have an issue.


768018
 

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I'm assuming that was still with the pump running.

Along with the inertia switch connection, there can be two or three others located under the master cylinder, and there is one just in front of the pump too. I don't have the 2005 wiring layout, only 2003. But Ford uses these connections, two or three, to move the fuel pump circuit around. There are a few wires that can look like pink with a black stripe. You are going to need to check these connections for corrosion. And if no corrosion at any of the connections, then it's hunting wires.



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