markrinker
New Member
2000 CAT 3126 375hp - does anyone here know if there is a lift pump between the tank and the RACORs, or does the injector pump work on suction?
Reason I am interested: My 'sync weirdness' (see other thread) is actually only at or near WOT, and increases under fuel/water/gear/people load. It also happens on BOTH port and starboard sides, which tend to rule out the syncronizer, as it only matches starboard RPMs to port.
I ran ~7hrs this holiday week at 2200rpm cruise without as much as a flinch in the sync. Increase the 'go-lever' to WOT and the intermittant port or starboard slow dance would start.
My theory at this point is that under high fuel draw conditions, the system is momentarily drawing air past an o-ring, fitting, or a bubble gets pulled out of the fuel itself. Postive fuel pressure between the tank and the primary filter will often solve these problems as it pushes the fuel through the filters, rather than the injector pump sucking it through. I have added lift pumps to GM work trucks in the past that were not originally fitted with them, and solved high load fuel starve problems.
Thinking that if my boat doesn't already have them, I'll mount them near the RACORs and wire them to be powered directly off their respective port/starboard alternator battery charge lead with an appropriate fuse for overload or short protection. This way, the only way the pump is pumping is with a running engine...
Thoughts? Comments?
Reason I am interested: My 'sync weirdness' (see other thread) is actually only at or near WOT, and increases under fuel/water/gear/people load. It also happens on BOTH port and starboard sides, which tend to rule out the syncronizer, as it only matches starboard RPMs to port.
I ran ~7hrs this holiday week at 2200rpm cruise without as much as a flinch in the sync. Increase the 'go-lever' to WOT and the intermittant port or starboard slow dance would start.
My theory at this point is that under high fuel draw conditions, the system is momentarily drawing air past an o-ring, fitting, or a bubble gets pulled out of the fuel itself. Postive fuel pressure between the tank and the primary filter will often solve these problems as it pushes the fuel through the filters, rather than the injector pump sucking it through. I have added lift pumps to GM work trucks in the past that were not originally fitted with them, and solved high load fuel starve problems.
Thinking that if my boat doesn't already have them, I'll mount them near the RACORs and wire them to be powered directly off their respective port/starboard alternator battery charge lead with an appropriate fuse for overload or short protection. This way, the only way the pump is pumping is with a running engine...
Thoughts? Comments?