ole truck starts fine but runs rough coughs and sputters so thought it needed new lift pump. put one on and it is hard to start, have to use fluid to start it but once it gets goin it runs great. whats that all aout? looked at some of this stuff on here and somebody said excess rail pressure may have lifted the relief valve. whats goin on,need help , thanks

 

Rail pressure on a 99?

First - scan for codes. The key on/off trick doesnt work at all on a 99 so you need an OBDII scanner.

Second - install a fuel pressure guage. If you dont know the details - ask and someone will help you.

Third - dont use starting fluid. Figure out what the problem is. Starting fluid and the grid heaters is not a good mix.


Also, welcome

 

like evil said you need to put a guage on it and see what kinda lift pump pressure you have...what kind of new lift pump did you install?.....could be too much fuel pressure sending the injection pump into a hard start mode.....was it an Airtex pump?....if so that could very well be the problem.....i've changed 5 in the last 2 months for that very problem...brand new pumps but causing a hard start problem, put new stock replacement carter lift pumps on them and the problem went away...from what i've been told the way the ecm knows there's too much pressure is from the amount of amperage on the lift pump circuit and best we can tell the newer airtex pumps arnt showing the right amperage and causing the hard start

 

Try connecting your power wire to a fuse that is hot with the key on(wipers, pwr win., etc.) The pump will prime up with the key turned on an shut down tempararily while the engine is cranking, then turns back on after key release.