Lift pump Diagnostics help needed? Do these lock up with age?

[97Suburban]

Hello,

I have a thread running here, but wanted to ask on main menu specifically about the lift pump diagnostics? So you can reply here or in the thread link below.

http://www.thedieselpageforums.com/tdpforum/showthread.php?t=37776


OK, as noted in the thread above, I swapped my 5 year old lift pump that seems to be working perfectly, based on always running anytime I turn on the switch.
But I am trying to diagnose the stalling issue, making sure the lift pump is good...? I suspect it is, but wanted to make sure and eliminate it.

I swapped out my seemingly good lift pump of 5 years then installed a backup lift pump that worked pefect when I swapped it out for maintenance 5 years ago and kept it for a traveling backup lift pump.

I swapped it out and when I first turned on the key, it worked fine pumping away...
But then after that first run it never turned back on again... then subsequent times of running the truck and trying to bleed the air out of the system, that lift pump refused to pump fuel to bleed the air out and would NEVER turn back on after the first time. It never worked again after it first pumped, I suppose it locked up from sitting wrapped up for 5 years? I did have the ends capped and in a zip lock bag. so it did NOT rust or anything. Does ANYONE have any thoughts on a lift pump locking up? I suspose she is toast and to toss it...
:mad:


Thanks again for all your help! ;)
:D

[DmaxMaverick]

If your pump failed, exactly as you describe, it wouldn't be the first time. They are electrical/mechanical devices, designed and manufactured by humans. They can fail after 1 minute of use, or (seemingly) never. I've seen several of both and everything in between. Apply 12V to it. If it pumps, it's probably good. If it doesn't pump, toss it, it isn't worth the hassle of guessing when it will work next. Also, check for Batt+ voltage at the pump connector when it fails. Your truck's electrical system was also designed/mfg'd by humans.

[97Suburban]

ok great, that makes sense, thanks DmaxMaverick, that fills in the blanks, wasn't sure how smart or finiky this lift pumps are, they look basic, but even though I am mechanical and do most of my own work, I have no real experience with these, nor was not sure what was inside these units and how smart they are and how they act or react or pressure sesnitive or fail, thanks.



If your pump failed, exactly as you describe, it wouldn't be the first time. They are electrical/mechanical devices, designed and manufactured by humans. They can fail after 1 minute of use, or (seemingly) never. I've seen several of both and everything in between. Apply 12V to it. If it pumps, it's probably good. If it doesn't pump, toss it, it isn't worth the hassle of guessing when it will work next. Also, check for Batt+ voltage at the pump connector when it fails. Your truck's electrical system was also designed/mfg'd by humans.

[97Suburban]

Hi DmaxMaverick,
Thanks, and educate me...

For a spare backup lift pump, or rather, in my other thread on the Heath PMD swap out under warranty, I will probably replace my lift pump for safety before my winter trips in a few months, tell me, I will save this good working 4+ year old lift pump and install a new one, but, before each 12 hour trip in winter, then in summer, can I simply hook a lift pump up to 12 volts and test it DRY or should I get kerosene or diesel in a can or something and test it to circulate for 15 mins non-stop or some procedure??? Then if good, carry it also with extra PMD and relays???

Thanks again!!
:D




If your pump failed, exactly as you describe, it wouldn't be the first time. They are electrical/mechanical devices, designed and manufactured by humans. They can fail after 1 minute of use, or (seemingly) never. I've seen several of both and everything in between. Apply 12V to it. If it pumps, it's probably good. If it doesn't pump, toss it, it isn't worth the hassle of guessing when it will work next. Also, check for Batt+ voltage at the pump connector when it fails. Your truck's electrical system was also designed/mfg'd by humans.

[DmaxMaverick]

I wouldn't go that far. I would store it full of fuel with the in/outlets capped, and sealed in a "Food-Saver" bag (toss in a Silica-gel pack). I do this a lot with long term stored items. Great for filters that stay under the truck seat for [years]. I also seal up model engines this way, too. Works well.

[AllThumbs]

I wouldn't go that far. I would store it full of fuel with the in/outlets capped, and sealed in a "Food-Saver" bag (toss in a Silica-gel pack). I do this a lot with long term stored items. Great for filters that stay under the truck seat for [years]. I also seal up model engines this way, too. Works well.

That's a great idea. Thanks.