Crx with D16z6 swap wont rev past 4k

[Spade1028]

ok so heres the deal, im in the process of buying a 89crx si. it has a d16z6 swap. i havent gone to see the car yet all i know of it is the pictures and talking to the owner who knows nothing about cars..awesome right? its a pretty clean car. he tells me it wont rev past 4000rpm and that it needs a new distributor and ecu and should run good. i already have both. is that what the engine needs ? the other odd thing is this "special" guy has just the air filter mounted directly to the throttle body, could it be a restriction of some type? im trying to look at all my possibilities before i go see the car this weekend this way i can hopefully get it to run right before i trade him vehicles.

[WeakSauce92]

It might possibly be the ecu if it already needs one.

[Spade1028]

the check engine light is on also..

[1992cxcivicEG]

air filter is fine, ecu is angry for some reason most likely its pissed about wiring, and its in safe mode

[Spade1028]

hmm,what would i have to do to get it out of safe mode? putting another ecu in wouldnt change anything then im assuming?