JEEZE - the change in the board has caused posts to scroll so quickly that the &quot;last 50 posts&quot; no longer keeps up, and I miss posts unless I actually retrace thru every forum I participate in - I was afraid that would happen - bummer! : <br><br>ANYWAY - to answer question directed my way - my pump setup was IMMEDIATELY installed after buying the truck so it's been on there nearly all its 13,000 miles - been a few minor changes, like the bypass I made for the pusher, but that's about it. PSI has remained constant, absolutely NO problems of any kind, and ALL filters are still the originals and showing NO drop in PSI at this time.<br><br>The relay is a low current coil type - and there's NO reason for concern about duty cycle or variations in current - in the first place, voltage/current pulsing only occurs at startup, and usually only cycles once - and relays of this type are MADE for frequent and rapid pulsing - that's their reason for existence! Just be sure to get a low coil current model, and one with heavy contacts - 10 amps at least for a decent margin of safety - 20 amps is better - they come in various values.<br><br>I would guess that under very low fuel flow conditions, like coasting down a long grade, fuel recirculation thru the LP motor (and pusher!) would be at maximum - hard to say how hot it would get, but the sample motor I provided pics of had over 100,000 miles on it, so use your own judgement - windings and commutator looked great...<br><br>I would think conditions might be worse under HEAVY fuel flow to the engine, when there was NO flow thru the pump because it was sending nearly ALL it's flow to the engine and none or at least much less is left to circulate thru the pump motor - and yeah - it blew ME away when I first heard that fuel actually passed THRU the motor!<br><br>Biggest question in my mind concerning the valve failures in these pumps, is WHY do they fail, and under what typical operation? Is it from pulsing from the VP-44's mechanical LP being &quot;reflected&quot; back to the Carter, or rapid &quot;flutter&quot;, as often happens in ball valves of this type at varying flow rates? Is it more likely under HIGH recirculating flow, or low flow that keeps the valve on/off its' seat? IF we could get the answer to that, we might be better prepared to provide a fix...<br><br>Alpine is right in the fact that there's not much to be done to mess with the built-in valve in the Carter LP - you have to destroy the pump to get it apart - but if a person figured the built-in valve WAS the greatest weak point, his idea of drilling and tapping a bolt thru the pump housing to mechanically hold the valve closed against it's seat, and THEN install a better quality EXTERNAL valve, might work, and CAN be done easily without damaging the pump - but leave the unknown as to require fuel flow thru the Carter pump motor for cooling and lubrication. Of course, there would always be fuel in that area from the still-open passage on the intake side, and perhaps that is sufficient...<br><br>nuff for now...

 

Dunno what makes the difference, but I direct-connect a hose about 2 feet long to the shrader valve at the inlet to my VP-44 - I use an electric sender on the other end - and have NO trace of guage pulsing installed that way...

Here's a pic of the sender and mount I use, the relay discussed earlier can be seen back on the firewall - it mounts to a bracked secured by a grounding bolt already in that position...

Do you suppose it's possible that the pulsing some report is NOT caused by the VP-44 - but rather from rapid open/close flutter of the ball valve in the lift pump, which would cause the same effect on a guage?