One of my objectors stopped working (1998 xj). I have a set from a 1991-1993, can I use this set?

 

I don't think so. Do some searching for flow rates though. I could be wrong.

 

'96-'98, 53030778, Grey, 23.2lb/hr@49psi (243cc/min@337KPa)=21.71lb/hr@43.5psi(228cc/min@300kpa)
12ohm
234cc @ 3 bar

91-'93, 33007127, Brown, 23.61Lb/hr@43.5psi (248cc@300kpa)
14.5ohm
240cc @ 3 bar

 

So nobody knows if I can just replace the one dead injector, or swap all six with no ill effects?

I know that 1996+ is a constant 49PSI on the rail and there is no return.
The pre 96 has a FPR and a return line. The 1991-1993 fuel pressure varies between 31-39psi. I have this rail and thought about swapping it, but I don't know what to do with the return line.

 

No, connectors are different.