hey whats up fellow roterheads, i have serious problem the 86 rx7 that i just bought has a straight pipe there are no cats (your are probably laughing) the guy i bought it from had a sad engine in it which i replaced,but it hesitates at 3900rpms. what do i do can i just put by a main cat an plug the port hose into it and expect normal performance.Also were does the o2 sensor wire originate from engine/a harness. please be specific https://www.nopistons.com/forums/pub...IR#>/dunno.gif https://www.nopistons.com/forums/pub...IR#>/dunno.gif https://www.nopistons.com/forums/pub...IR#>/dunno.gif https://www.nopistons.com/forums/pub...IR#>/dunno.gif https://www.nopistons.com/forums/pub...IR#>/dunno.gif https://www.nopistons.com/forums/pub...IR#>/dunno.gif https://www.nopistons.com/forums/pub...IR#>/dunno.gif

So right now, the backpressure split air tube is not hooked up? Yes, you should hook that up to your main cat and make sure your 6 port actuators are moving freely. I'm not sure about the O2 on the harness. Is their no O2 sensor either?

i have an o2 in the exaust manifold but its disconnected,thanks man for the info

that o2 sensopr doesnt matter for **** when ur not running ur cats. at least i think, **** i just left mine off

The o2 sensor goes into the main engine wiring harness under the intake manifolds, near the primary fuel rail. So why do you want to put cats back on? They are serious perfomance hinderance. You need the split air tube, it opens the 5-6the ports. So no don't plug it. If you have a stright pipe on there, you should make a litte bung of some sorts and run a vac hose the 5-6th ports, to open them. The hesitation can be many thing, bad grounds, bad wiring, bad secondary injectors, bad ecu. Since you purchas have you done all the regular maintence? ie: plugs/wires/filters/fluids etc?