Pusher Pump and Priming Cycle Behavior

[Neal Cassady]

Just finished up the pusher pump install last night, got the wires back in the loom and taped everything up nice and neat. Decided to run the priming cycle as a test, bumped the starter and there were two or three small hesitations in the pump sound(s) before the pusher took off and ran at full speed. I had done this to test the system during the install and never noticed it before.



I am using the positive (yellow) wire of the factory lift pump pump to trigger the relay that provides power to the pusher pump. I have the pusher grounded at pump mount and the relay grounded at the firewall.



Truck runs fine, cruises at around 16 lbs, idles at little higher and I have only been able to pull it down to around 13/14 lbs at under hard acceleration. The priming cycle, once it gets going, will peg the gauge beyond 16 lbs.



Anybody else with a similar pusher setup observe this type of behavior?



Thanks,

Dave

 

[Todd T]

Ive only used my prime cycle once or twice but cant remember it doing anything that was alarming to me.



it sounds like it is working well other than the studder on prime? i dont think i would worry about it.

 

[Steve St.Laurent]

I don't recall anything like that on mine. Since it was the first time you ran the pump remember that you had a LOT of air in those lines, the pump probably sounds a lot different when it's pumping air rather than fuel - just a guess.

 

[Neal Cassady]

Steve,



Wasn't the first time I ran the pump, I have been running the setup for over a week, just hadn't had the time to put the factory lift pump wires back in the loom and tape it up. I ran the priming cycle after I had all the wires buttoned up to test the operation of the pusher pump, that is when I first noticed the little hesitation sounds.



This was the first time I ran the priming cycle with a full tank of fuel but I don't think that would make a difference.



Dave

 

[Neal Cassady]

Update--Looks Electrical

Did some testing with the multimeter when I got home from work.



The 1 to 1. 5 second pulse off electricity when the key is turned to the run posistion works fine. There is about 7 volts for a second or so measured at the pusher pump and the factory lift pump.



When I bump the starter to initiate the lift pump priming cycle there are 3 pulses of approx. 6 or 7 volts that correspond with the noise that I am hearing at the pusher pump. After the 3 pulses there is approx. 12. 5 volts at the pusher pump as well as the factory lift pump. The needle moves quickly across the fuel pressure gauge and pegs it at 16 lbs plus.



When the truck is running I am seeing approx. 13 volts at the pusher pump and the factory lift pump. I took all measurements on both sides of the relay to see if there were any differences, I didn't see any.



Dave