Help! Goofy fuel guage

From : Annonymous

Q: i installed an elec. fuel gauge 0-30 in march everything was fine. average fuel pre. was 12 at idle 18 crusing at 1750 rpm and would clime as high as 24 with wot. coming home a week ago i was accelerating onto the interstate when the fuel pressure jumped to 28psi egt was 680 boost was 15. the fuel came back down to it normal range. the next morning i was heading to town fuel pressure climes to 27.4 after about 2 miles it shot up to 33 before the gauge went into error mode. it has been that way since. when i crank it up in the morning fuel pressure is 26.x any increase in rpm causes the gauge to top out. i removed the sending unit from its mount on the fender and installed my fuel injection test gauge bounce! the needle looked like a fan blade up to 40psi down to 15psi i also noticed the fuel line was throbbing. i am thinking of replacing the fuel gauge with a manual gauge but all that needle sweep has me nervous. suggestion advice & commits requested. -- billy 1995 ram 2500 4x4 cummins .

Replies:

From : tom lawrence

interstate when the fuel pressure jumped to 28psi egt was 680 boost was 15. the fuel came back down to it normal range. well that depends on what you consider normal. cummins says 8-24psi at idle 28-36psi at 2000rpm/no load. when i crank it up in the morning fuel pressure is 26.x any increase in rpm causes the gauge to top out. yeah - its a little high. i would replace the spring in your overflow valve. oh and replace the gauge with a 0-60psi gauge as 30psi is acceptable and normal on a 12v. i removed the sending unit from its mount on the fender and installed my fuel injection test gauge bounce! the needle looked like a fan blade up to 40psi down to 15psi i also noticed the fuel line was throbbing. yep. as with most diesel fuel systems you need a snubber - something to damp the pressure spikes. most guys just use a needle valve in-line and just open it enough to register pressure on the gauge. on my gauge i feed the sending unit with about 3 feet of 1/8 od tubing - the id is small enough that the pressure spikes are attenuated. thinking of replacing the fuel gauge with a manual gauge but all that needle sweep has me nervous. im a fan of electric gauges inside the cab - the only mechanical gauge i have is a boost gauge because a little air never hurt anyone. a continuous stream of diesel on the other hand.... isolators are one solution but i spent too much time jerking around with mine futzing with the diaphragms replacing lost coolant etc. - my autometer electric fuel pressure gauge has served me well for 18 months. .

From : Annonymous

normal was 12 - 18 psi that is what i have been reading since i installed the gauges. maybe the spring was sticking in the open position and now it is stuck closed. how hard is it to replace my conundrum is the manual will run me $150 with a isolator and the elec is $250. i bought this truck in july of 05 and have spent about 7 large on enhancements very little of this was related to the motor. i am in fear of my wife finding my maintenance log. -- billy 1995 ram 2500 4x4 cummins .

From : christopher thompson

normal was 12 - 18 psi that is what i have been reading since i installed the gauges. maybe the spring was sticking in the open position and now it is stuck closed. how hard is it to replace my conundrum is the manual will run me $150 with a isolator and the elec is $250. i bought this truck in july of 05 and have spent about 7 large on enhancements very little of this was related to the motor. i am in fear of my wife finding my maintenance log. -- billy 1995 ram 2500 4x4 cummins uh maybe you should run two logs *grin* -- -chris 05 ctd 06 liberty crd real trucks dont need spark plugs .