kirtondog23

I put a 6.0 Lq4 in my 1990 chevy K 2500. I replaced the fuel pump with a Master E3270.

My engine is running lean. (first it was just the left bank P0174, but now is showing on both sides)

The guys at Tunex were not able to find any air leaks in intake or exhaust. They think the problem is in the fuel delivery. They say injectors check out ok.

My fuel pressure is generally around 55 psi but the PSI will jump around a lot. ( I understand that fuel should be from 55 to 62 psi, correct if wrong.) Problem is I can't remember if I replaced the fuel filter or not. I did replace some fuel lines so I may have done the filter but I don't know. Also is the fuel filter for the tbi350 different enough from the filter on the 2004 6.0 to warrant a problem there?

Do the symptoms, fuel psi jumping around indicate the filter? or did I put in the wrong pump?

Thanks for all your help.

As for how the truck is running now it seems to be overcompensating for the lean code and running rich enough to heat up the exhaust super hot.

454SuperSport

well, first thing i need to know is the fuel rail a return style (99-03 feed and return lines) or not (04+ only a feed line). fuel pressure should be 58psi. also, fuel filters are the same for all 1988+ trucks. give me some more info on the fuel system.

kirtondog23

Thanks for the help. My new system is an 04.

So my 1990 fuel filter for the TBI engine is the same as the new ones?

Thanks and let me know what I should check.