Kennedy lift pumps
- Thread starter ZeroGravity58
- Start date
i have twin kennedys, black ones, and have been chasing a problem due to lack of pressure. I've bled them like John described, checked all my lines and changed filter. It's either got to be the pump(s) or something in the tank.
I get 4 psi with BOTH wired up, and 0psi with only one wired up. Yet I can wire one at a time and hear it come on, both pumps do this.
With both pumps on at WOT, it drops to 0psi, heck not even WOT drops it to 0psi.
I may need to take my tank off i guess and check the pickup(Trippin pickup) and I need to prolly go with the Airdog II,
What did you ever do with yours OP?
I get 4 psi with BOTH wired up, and 0psi with only one wired up. Yet I can wire one at a time and hear it come on, both pumps do this.
With both pumps on at WOT, it drops to 0psi, heck not even WOT drops it to 0psi.
I may need to take my tank off i guess and check the pickup(Trippin pickup) and I need to prolly go with the Airdog II,
What did you ever do with yours OP?
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what pump are you running now? I thought about the mitusa, but figure I'll go with airdog II, I just want to know for sure if the KDs are bad or if I have another fueling issue.
If I have to replace the cp3, I'd rather go with one of Wickeds pumps.
Have you pressure tested your lift pump? Mine was bad even though it was not visibly in bad shape (2 months old before I figured out it wasn't working to be exact), and I could still hear the pump running it just wouldn't build any pressure atall
no i haven't, how would i do such?
i hear mine on, with both wired up or with just one wired up. And either pump bleeds to the fuel filter, yet only 4psi on gauge, or 0psi with one wired.
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hook up a pressure gauge to the filter head with an adapter from Lubercation Specialits. Or you could just put a cheap pressure gauge inline after your pump. Or the redneck way would be to unhook the fuel line on the pressure side of your pump, and tried to hook back fuel with the key in run position. You should only be able to hold back the gravity fed fuel, pretty much any positive pressure will get very hard to hold back with your finger :thumb:
Sorry I should have wrote that differently.
Tested the pressure of your lift pump, instead of saying pressure testing it... Sorry for the confusion
EDIT: When I first installed my faulty fuel pump, it had and continuely had enough force to start the vehicle without hand priming the filter head, but that was all the pressure I had so don't think just cause you didn't have to prime it on sartup means you have any working pressure... Mine could have been less than 1 psi (just enough to lift alittle bit of fuel)
Tested the pressure of your lift pump, instead of saying pressure testing it... Sorry for the confusion
EDIT: When I first installed my faulty fuel pump, it had and continuely had enough force to start the vehicle without hand priming the filter head, but that was all the pressure I had so don't think just cause you didn't have to prime it on sartup means you have any working pressure... Mine could have been less than 1 psi (just enough to lift alittle bit of fuel)
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i meant the big berthas and such the cp3s.
on side note: i find weird, I just wired up lift pumps to a switch(controlling both) turned em on and ran truck....every time I turn the pumps off, the truck gets a bumpy idle, makes me think it's starving for fuel. Turn the pumps back on and it quits, pumps off and bumpy inconsistent idle, but it is very hard to notice, has to be completely silent and I have to be very still.
for some time now, my truck takes longer to turn over, quite a bit longer that it used to or than a new one, even if I leave ignition on a few seconds to let the lift pumps push fuel.
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I have a fitting and gauge hooked to filter head like you speak. This is how I"m getting my readings of 0-4psi. It pours out of the filter head when i'm priming/bleeding with the pumps.(without hand pumping)
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www.fuelab.com
Probably one of the nicest looking pumps I have ever seen. I bought it for my truck but we decided to test it on Abby first. Same price with an inline filter and regulator as an airdog or FASS-just no plumbing or wiring to go with them.
Ya it know about the colors but red is the one most know lol and that is also the color most shops have is stock.
Well we need it on Abby and running so we can see how well it does as I have one on a old truck back in Ontario but dont want to pull it off the truck till I know diesel wont kill in in a week.
Well we need it on Abby and running so we can see how well it does as I have one on a old truck back in Ontario but dont want to pull it off the truck till I know diesel wont kill in in a week.
so it must be a 41403. The one my truck in Ontario is a 41401 so it is not as much flow humm the 300SD might like it lol.
I don't think my old one said "Compatible with gasoline, diesel, methanol, and ethanol" when I got it so it might be just the newer ones still need to look into it.
Thanks for all the info.
But back on topic of kennedy pumps I dont have any or even played with them so I am not much help.
I don't think my old one said "Compatible with gasoline, diesel, methanol, and ethanol" when I got it so it might be just the newer ones still need to look into it.
Thanks for all the info.
But back on topic of kennedy pumps I dont have any or even played with them so I am not much help.
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I have a single KD on my truck right now and if I was to add a second, I think I would plumb it in parallel not in series the way KD says to. Simply because it is not a positive displacement pump, but a centrifugal one. Two centrifugal's in series don't work as well as they do in parallel. In series, the one pump can actually cause the other to lose prime and make it pretty much useless.
Centrifugal pumps in series compound pressure. In parallel they compound volume. In either case, once primed, they will stay primed. Don't know where that info is coming from....
Advantages of a centrifugal pump over a positive displacement is that it does not require a regulator and when dead, still flows. Down sides are that they don't self prime well and the pressure rise is usually much smaller than a positive displacement.
Flow wise, you have to size the pump the application in both cases. Don't whine because your 20 GPM pump isn't keeping up with your 50 GPM demand.
Advantages of a centrifugal pump over a positive displacement is that it does not require a regulator and when dead, still flows. Down sides are that they don't self prime well and the pressure rise is usually much smaller than a positive displacement.
Flow wise, you have to size the pump the application in both cases. Don't whine because your 20 GPM pump isn't keeping up with your 50 GPM demand.