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Discussion Starter #1
I'm restoring a 2002 FLHTCUI that sat for many years in a neighbor's garage. First major project was rebuilding the fuel pump assembly. With the assembly complete, I've attempted to "trial" the pump outside the bike by submerging the strainer in bucket of gas and hooking the power cord from the bike. The pump will cycle on for 2-3 seconds and then shut off when I engage the run button. No gas is being pumped through the line. I expected it would pump gas through the assembly and back into the bucket since there was no pressure until I turned off the switch. Not the case. Should I cover the exit hole on the regulator to create a vacuum? Little help here, if possible... thanks!
 

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Normal operation is when you first apply power the ECM will activate the pump for a second or so to get pressure up. Once the engine is running the pump will run continuously.
 

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Discussion Starter #3
Thanks for your reply RustyG...
I can understand that when a bike has been running previously and still has fuel in the lines. However, this bike has NO fuel in the system due to the rebuild. I was assuming the pump would run until the lines were full. How do I rectify this issue? Does the pump not recognize the presence or absence of pressure? Thanks.
 

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Just pull the fuel pump relay and jump power to load. I use a manual relay with a thumb switch, but you can just use a piece of wire. Then the pump should run anytime the switches are on.
 

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Discussion Starter #5
Thank you, Thermodyne. Unfortunately for me, I'm barely above novice level regarding electrical maneuvers... and your suggestion is for what is most likely a novice-level action, but still above my understanding. I'm trying to work on that. However, my question remains as to whether this is what I should expect from a fuel pump... the intermittent run time (2-3 seconds) per activation regardless of fuel pressure. I would think this would certainly hold true for an active bike, but not necessarily for a rebuild process when the system is completely dry & devoid of pressure.

Interestingly, my repeated trials with the strainer submerged will not coax any fuel at all into the line attached to the pump. I've run a succession of 6 or so "0n-off" cycles per trial with no results. Even if the pump was somehow reversed, one would think there would be air bubbles in the strainer.

I do have a replacement pump coming in tomorrow and will see if it performs differently. This in-tank install activity is rather tedious... I'd prefer to have a good idea that the process is working before doing it again. Again, thanks for your input!
 

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At key on it runs for a second or so. Then it does not run again until the engine is cranked and or running.
 

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Discussion Starter #7
Excellent. Then how does a rebuild get the initial gas to crank? Does the fuel pump activate and run constantly while the engine is cranking? Should I simply run the starter until it pulls the gas up through the lines to create full pressure allowing for ignition? Since my trials didn't pull any gas from the pump, I suppose I'll wait and try the new pump to see if it reacts differently. If it pulls the fuel, then the cranking activity shouldn't take too long to fill her up.
 

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What exactly does "rebuilding the fuel pump assembly " mean? Part by part, what did you replace, what did you "rebuild?"
 

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Continuous pump operation is triggered by pressing the start button to crank.and continues with the engine running. Installing the whole fuel pump assembly back into the gas tank is a pita and the original HD shop manual gives short instructions to get it done and still it is tedious fumble job.

Armin.
 

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Discussion Starter #10
Good morning, all. I replaced the pump, filter, regulator & the fuel sending unit... plus had the wiring replaced due to some skinned and broken insulation along the run. I was able to reuse the pump and plate connectors. The bracket itself and the tank plate were cleaned thoroughly.

Oh, yeah... it's a definite pain to extract and reinstall the assembly. That is why I was hoping to test the pump prior to the actual install by pumping some fuel through the lines. Apparently, the 2-3 seconds run time is insufficient to get the fuel moving through the strainer and pump, as it will not even reach the fuel line on top of the pump, much less send it through the lines. I've been hesitant to run the starter for long periods without fuel in the lines, but this may be necessary to get the fuel moving. I've replaced the engine, primary and tranny fluid, plus the plugs, so I suppose the only problem with that would be battery drain.

So, just to be sure... when the "run/off" switch is engaged all I'll get is the 2-3 seconds of pump run per cycle... regardless of whether the strainer is submerged or not, and regardless of whether there is any fuel pressure built up...?
In addition, when the run/off switch is on and I engage the starter for cranking the pump will kick on & run for the duration of the starter run cycle? If so, this will be my next trial to see if extra pump run time will flow the fuel.

Appreciate all of you comments. Always had carbed bikes before... this EFI thing is new to me. I'm getting there, I hope.
 

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If you feel it is necessary to test the pump before you install it in the tank, couldn't you just run it on an external power source being careful not to make and break the circuit close to the fuel so a spark doesn't ignite it?
 

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Thank you, Thermodyne. Unfortunately for me, I'm barely above novice level regarding electrical maneuvers... and your suggestion is for what is most likely a novice-level action, but still above my understanding. I'm trying to work on that. However, my question remains as to whether this is what I should expect from a fuel pump... the intermittent run time (2-3 seconds) per activation regardless of fuel pressure. I would think this would certainly hold true for an active bike, but not necessarily for a rebuild process when the system is completely dry & devoid of pressure.

Interestingly, my repeated trials with the strainer submerged will not coax any fuel at all into the line attached to the pump. I've run a succession of 6 or so "0n-off" cycles per trial with no results. Even if the pump was somehow reversed, one would think there would be air bubbles in the strainer.

I do have a replacement pump coming in tomorrow and will see if it performs differently. This in-tank install activity is rather tedious... I'd prefer to have a good idea that the process is working before doing it again. Again, thanks for your input!
So, you have a replacement pump coming to replace the new one you just "tested"?
 

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Good morning, all. I replaced the pump, filter, regulator & the fuel sending unit... plus had the wiring replaced due to some skinned and broken insulation along the run. I was able to reuse the pump and plate connectors. The bracket itself and the tank plate were cleaned thoroughly.

Oh, yeah... it's a definite pain to extract and reinstall the assembly. That is why I was hoping to test the pump prior to the actual install by pumping some fuel through the lines. Apparently, the 2-3 seconds run time is insufficient to get the fuel moving through the strainer and pump, as it will not even reach the fuel line on top of the pump, much less send it through the lines. I've been hesitant to run the starter for long periods without fuel in the lines, but this may be necessary to get the fuel moving. I've replaced the engine, primary and tranny fluid, plus the plugs, so I suppose the only problem with that would be battery drain.

So, just to be sure... when the "run/off" switch is engaged all I'll get is the 2-3 seconds of pump run per cycle... regardless of whether the strainer is submerged or not, and regardless of whether there is any fuel pressure built up...?
In addition, when the run/off switch is on and I engage the starter for cranking the pump will kick on & run for the duration of the starter run cycle? If so, this will be my next trial to see if extra pump run time will flow the fuel.

Appreciate all of you comments. Always had carbed bikes before... this EFI thing is new to me. I'm getting there, I hope.
What Thermodyne was trying to tell you is just to get constant power to the pump to see if it runs. That's all you want to do right? Why are you getting all hung up on what the electronic components do in various situations? Nothing you are doing will change how the relay, ignition circuit, or the ECM work so I don't understand the concern with all of that.

Power the pump to see if it works, then install it in the tank and ride.
 
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Discussion Starter #14
Thanks, guys. I suppose the alternative power source is the best way to bypass the restrictions of the bike's system to ensure that the pump is gonna do its job. Just trying to learn here as all of this EFI stuff is new to me. Again, your input has been valuable.
 

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therm answered your question in his first reply,, may have been over your head.. we call it bench testing, as in supplying power to the component outside the bikes electrical system so as to have the correct power available.. if the pump does not run correctly,, it is a safe bet to toss it.
 

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Discussion Starter #16
Latest: I was able to create a bench test & the fuel flowed well throughout the pump assembly. Installed in the tank & verified pump running for the prescribed 2-3 seconds via on-off switch. However, when attempting to bust her off via the starter button there is no ignition. I’ve allowed the starter to crank for approx 10 seconds a couple of times with no indication of firing activity.

How can I be sure the fuel is actually making it to the injectors? Are there any related relays that would be subject to failing due to years of inactivity that could affect the starting processes? The plugs are newly replaced.Your continued suggestions are appreciated.
 

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If the pump is running then you need to do a pressure test. You'll need a special pressure gauge hookup that attaches to the "check valve" on the tank.

Sent from my VS995 using Tapatalk
 

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How can I be sure the fuel is actually making it to the injectors? Are there any related relays that would be subject to failing due to years of inactivity that could affect the starting processes? The plugs are newly replaced.Your continued suggestions are appreciated.
Do you own a set of manuals for this bike?
 

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Discussion Starter #19
Thanks for the replies. I have an online manual. I’m replacing the tank check valve with hose from it to regulator. My indie will check the pressure at his shop as I don’t own a tester... yet.
 

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I have an online manual.
Dump it and get a REAL Harley Davidson manual. Available only in print.

Sent from my SM-G965U using Tapatalk
 
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